Director of National Intelligence couldn’t explain 143 of 144 UFOs
#space #Extraterrestrial #UFO #UAP #Unexplained
Leaked information from intel officials says there is no evidence that aliens are responsible for recent UFO sightings, but they are also not being ruled out. Investigative filmmaker Jeremy Corbell reacts.
Even if the UFOs that hundreds of military pilots and thousands of everyday citizens have spotted are extraterrestrial in origin, they are likely far too complex for us to understand, UFO experts told Fox News in the wake of an inconclusive report released Friday by the Director of National Intelligence on unidentified aerial phenomena (UAP).
The report, which was ordered by Congress last year, examined 144 reports of UAPs from U.S. government sources since 2004.
Eighty of the reported incidents were observed with multiple sensors, including “radar, infrared, electro-optical, weapon seekers, and visual observation.”
In 18 of the incidents, “unusual UAP movement patterns or flight characteristics” were observed, including the ability to “remain stationary in winds aloft, move against the wind, maneuver abruptly, or move at considerable speed, without discernable means of propulsion.”
Despite the intriguing sightings, U.S. intelligence analysts could only explain one of the sightings, which was a large balloon deflating.
Colonel John B. Alexander, who developed an interagency task force to explore UFOs while in the U.S. Army in the 1980s, said that if the phenomena are extraterrestrial, they are likely far beyond what humans are capable of understanding with our current faculties.
“Whatever this is, it is more complex than we can possibly imagine,” Alexander told Fox News. “We’re not at the point of even asking the right questions, much less expecting simple answers.”
Military pilots have seen dozens of UFOs in recent years. (Department of Defense)
Seth Shostak, a senior astronomer at the SETI Institute who is doubtful that these UAPs are extraterrestrial, pointed out that aliens would nonetheless have technology that is incomprehensibly more advanced than what we’re accustomed to.
“The universe is three times as old as the earth. There’s plenty of time for societies to arise that are not just a thousand years more advanced than we are, but they could be a billion years more advanced than we are,” Shostak told Fox News.
“So if you ask yourself, ‘What could that kind of a society do?’ There are things they could do that we simply can’t conceive of.” Video
Shostak bets that humans will have better luck looking to the stars to find aliens than scouring our own atmosphere.
“We’re not looking for them a couple of miles up. We’re looking for them lightyears away,” Shostak said. “We look at star systems, other suns that are relatively nearby, that are either known to have planets and maybe planets like earth.”
A study published in The Astronomical Journal last year found that there are likely billions of Earth-like planets just in our galaxy.
Even if these UAPs aren’t proof of extraterrestrial life, Alexander agreed that aliens are out there, in some form or another.
“Is there life elsewhere in the universe? The answer is yes, and that’s not speculation, that’s math,” Alexander said. “That’s just based on the number of Earth-like planets or inhabitable planets that are out there.”
Don’t worry, but a huge comet is headed toward our sun. Scientists found it while studying old images from 2014 to 2018 taken for the Dark Energy Survey. Two University of Pennsylvania astronomers, Pedro Bernardinelli and Gary Bernstein, spotted the object heading inward from the Oort Cloud, possibly from as far as half a light-year away. Many have been calling it a mega comet.
The object was originally designed 2014 UN271. It’s now been officially named Comet Bernardinelli-Bernstein, for its discoverers.
It’s thought to be the largest comet yet discovered, possibly as big as a dwarf planet. It’s still far away and hard to see, but the current estimate suggests its nucleus, or core, is between 62 to 230 miles (100 to 370 km) in diameter. Whoa! That’s big for a comet.
The mega comet is not coming very close to us. It’ll make its closest approach in 2031, when it’ll sail just outside of the orbit of our sun’s 6th planet, Saturn. Saturn’s orbit is some nine and a half times farther from the sun than Earth’s orbit. So there’s no danger to us here.Must Watch Sky Events in 2021
Pedro Bernardinelli announced the discovery on Twitter on June 19, 2021.
Mega comet will near Saturn by 2031
The scientists scoured the survey images and discovered 2014 UN271 moving from 29 astronomical units, or AU (1 AU is the distance between Earth and the sun), to 23 AU. At its closest approach, 2014 UN271 will come within about 10 AU to the sun, which is in the realm of Saturn. Scientists didn’t find just this mega comet, though. The full search of the six years of survey data for trans-Neptunian objects turned up more than 800 objects.
Is 2014 UN271 the largest comet yet?
So the current estimate is that 2014 UN271 is between 62 to 230 miles (100 to 370 km) in diameter. If it turns out to be at the larger end of that range, it would be the largest Oort Cloud object yet discovered. (Comet Sarabat of 1729 is potentially the largest comet ever seen, with size estimates of 100 km, about 60 miles, in diameter. Comet Sarabat came much closer, within 3 AU of Earth, during its closest pass.) Whether 2014 UN271 takes on a traditional comet appearance and will grow a coma or a tail is yet to be seen. Scientists will have their eyes trained on the mega comet as it nears Saturn in 2031.
2014 UN271’s unusual orbit, which takes it from deep in the Oort Cloud straight in toward the sun, is hundreds of thousands of years long, the exact number yet to be determined. Despite its large size for a comet and nearness to us in 2031, astronomers do not expect the mega comet to brighten enough for us on Earth to see without powerful telescopes.
Scientists are working on a paper about the new object, which should be published in the new few months.
Bottom line: Scientists discovered a new object headed toward the inner regions of the solar system. 2014 UN271 may be the largest Oort Cloud object currently known.
UFO report: Do Americans believe something’s out there?
The US government has said it has no explanation for dozens of unidentified flying objects seen by military pilots.
A Pentagon report released on Friday says of 144 reports made about the phenomena since 2004, all but one remain unexplained.
It does not rule out the possibility that the objects are extra-terrestrial.
Congress demanded the report after the US military reported numerous instance of objects seen moving erratically in the sky.
The Pentagon then established the Unidentified Aerial Phenomena Task Force last August to look into the reports.
The group’s job was to “detect, analyse and catalogue” these events, as well as to “gain insight” into the “nature and origins” of UFOs, the Pentagon said.
Did the report reveal anything new?
The interim report released on Friday said most of the 144 reported cases of the “unidentified aerial phenomena” (UAP), came in the last two years, after the US Navy put in place a standardised reporting mechanism.
In 143 of the reported cases, they “lack sufficient information in our dataset to attribute incidents to specific explanations”.
Crucially, it said there were “no clear indications that there is any non-terrestrial explanation” for the aircraft, but also did not rule it out.
UAP “probably lack a single explanation”, the report said. Some could be technologies from another nation like China or Russia, others could be natural atmospheric phenomena like ice crystals that could register on radar systems, while the report also suggested some could be “attributable to developments and classified programs by US entities”.
The one case they could identify “with high confidence” was identified as “a large, deflating balloon”, the report said.
It added that the UAP posed “a clear safety of flight issue and may pose a challenge to US national security”.
The taskforce is now “looking for novel ways to increase collection” of reports and gather more information, adding that “additional funding” could “further study of the topics laid out in this report”.
What evidence is there?
The US Department of Defense released videos of the UAPs in April 2020. It said they had been filmed by the US Navy.
In a CBS News 60 Minutes episode last month, two former Navy pilots discussed seeing an object in the Pacific Ocean that appeared to mirror their movements.
One pilot described it as a “little white Tic-Tac-looking object”, referring to the white oblong mints.
“And that’s exactly what it looked like, except it was travelling very fast and very erratically and we couldn’t anticipate which way it was going to turn or how it was manoeuvring the way that it was, or the propulsion system,” witness and former Navy pilot Alex Dietrich told BBC News.
“It didn’t have any apparent smoke trail or propulsion. It didn’t have any apparent flight control surfaces to manoeuvre in the way that it was manoeuvring.”
SCOPE AND ASSUMPTIONS. .Scope. This preliminary report is provided by the Office of the Director of National Intelligence (ODNI) in response to the provision in Senate Report 116-233, accompanying the Intelligence Authorization Act (IAA) for Fiscal Year 2021, that the DNI, in consultation with the Secretary of Defense (SECDEF), is to submit an intelligence assessment of the threat posed by unidentified aerial phenomena (UAP) and the progress the Department of Defense Unidentified Aerial Phenomena Task Force (UAPTF) has made in understanding this threat.
This report provides an overview for policymakers of the challenges associated with characterizing the potential threat posed by UAP while also providing a means to develop relevant processes, policies, technologies, and training for the U.S. military and other U.S. Government (USG) personnel if and when they encounter UAP, so as to enhance the Intelligence Community’s (IC) ability to understand the threat. The Director, UAPTF, is the accountable official for ensuring the timely collection and consolidation of data on UAP. The dataset described in this report is currently limited primarily to U.S. Government reporting of incidents occurring from November 2004 to March 2021. Data continues to be collected and analyzed.
ODNI prepared this report for the Congressional Intelligence and Armed Services Committees. UAPTF and the ODNI National Intelligence Manager for Aviation drafted this report, with input from USD(I&S), DIA, FBI, NRO, NGA, NSA, Air Force, Army, Navy, Navy/ONI, DARPA, FAA, NOAA, NGA, ODNI/NIM-Emerging and Disruptive Technology, ODNI/National Counterintelligence and Security Center, and ODNI/National Intelligence Council.
Assumptions. Various forms of sensors that register UAP generally operate correctly and capture enough real data to allow initial assessments, but some UAP may be attributable to sensor anomalies.
EXECUTIVE SUMMARY. The limited amount of high-quality reporting on unidentified aerial phenomena (UAP) hampers our ability to draw firm conclusions about the nature or intent of UAP. The Unidentified Aerial Phenomena Task Force (UAPTF) considered a range of information on UAP described in U.S. military and IC (Intelligence Community) reporting, but because the reporting lacked sufficient specificity, ultimately recognized that a unique, tailored reporting process was required to provide sufficient data for analysis of UAP events.
• As a result, the UAPTF concentrated its review on reports that occurred between 2004 and 2021, the majority of which are a result of this new tailored process to better capture UAP events through formalized reporting.
• Most of the UAP reported probably do represent physical objects given that a majority of UAP were registered across multiple sensors, to include radar, infrared, electro-optical, weapon seekers, and visual observation.
In a limited number of incidents, UAP reportedly appeared to exhibit unusual flight characteristics. These observations could be the result of sensor errors, spoofing, or observer misperception and require additional rigorous analysis. There are probably multiple types of UAP requiring different explanations based on the range of appearances and behaviors described in the available reporting. Our analysis of the data supports the construct that if and when individual UAP incidents are resolved they will fall into one of five potential explanatory categories: airborne clutter, natural atmospheric phenomena, USG or U.S. industry developmental programs, foreign adversary systems, and a catchall “other” bin.
UAP clearly pose a safety of flight issue and may pose a challenge to U.S. national security. Safety concerns primarily center on aviators contending with an increasingly cluttered air domain. UAP would also represent a national security challenge if they are foreign adversary collection platforms or provide evidence a potential adversary has developed either a breakthrough or disruptive technology.
After carefully considering this information, the UAPTF focused on reports that involved UAP largely witnessed firsthand by military aviators and that were collected from systems we considered to be reliable. These reports describe incidents that occurred between 2004 and 2021, with the majority coming in the last two years as the new reporting mechanism became better known to the military aviation community. We were able to identify one reported UAP with high confidence. In that case, we identified the object as a large, deflating balloon. The others remain unexplained. • 144 reports originated from USG sources. Of these, 80 reports involved observation with multiple sensors. o Most reports described UAP as objects that interrupted pre-planned training or other military activity.
UAP Collection Challenges. Sociocultural stigmas and sensor limitations remain obstacles to collecting data on UAP. Although some technical challenges—such as how to appropriately filter out radar clutter to ensure safety of flight for military and civilian aircraft—are longstanding in the aviation community, while others are unique to the UAP problem set.
• Narratives from aviators in the operational community and analysts from the military and IC describe disparagement associated with observing UAP, reporting it, or attempting to discuss it with colleagues. Although the effects of these stigmas have lessened as senior members of the scientific, policy, military, and intelligence communities engage on the topic seriously in public, reputational risk may keep many observers silent, complicating scientific pursuit of the topic. • The sensors mounted on U.S. military platforms are typically designed to fulfill specific missions. As a result, those sensors are not generally suited for identifying UAP. • Sensor vantage points and the numbers of sensors concurrently observing an object play substantial roles in distinguishing UAP from known objects and determining whether a UAP demonstrates breakthrough aerospace capabilities. Optical sensors have the benefit of providing some insight into relative size, shape, and structure. Radiofrequency sensors provide more accurate velocity and range information.
But Some Potential Patterns Do Emerge. Although there was wide variability in the reports and the dataset is currently too limited to allow for detailed trend or pattern analysis, there was some clustering of UAP observations regarding shape, size, and, particularly, propulsion. UAP sightings also tended to cluster around U.S. training and testing grounds, but we assess that this may result from a collection bias as a result of focused attention, greater numbers of latest-generation sensors operating in those areas, unit expectations, and guidance to report anomalies. And a Handful of UAP Appear to Demonstrate Advanced Technology In 18 incidents, described in 21 reports, observers reported unusual UAP movement patterns or flight characteristics.
Some UAP appeared to remain stationary in winds aloft, move against the wind, maneuver abruptly, or move at considerable speed, without discernable means of propulsion. In a small number of cases, military aircraft systems processed radio frequency (RF) energy associated with UAP sightings.
The UAPTF holds a small amount of data that appear to show UAP demonstrating acceleration or a degree of signature management. Additional rigorous analysis are necessary by multiple teams or groups of technical experts to determine the nature and validity of these data. We are conducting further analysis to determine if breakthrough technologies were demonstrated.
UAP PROBABLY LACK A SINGLE EXPLANATION. The UAP documented in this limited dataset demonstrate an array of aerial behaviors, reinforcing the possibility there are multiple types of UAP requiring different explanations. Our analysis of the data supports the construct that if and when individual UAP incidents are resolved they will fall into one of five potential explanatory categories: airborne clutter, natural atmospheric phenomena, USG or industry developmental programs, foreign adversary systems, and a catchall “other” bin. With the exception of the one instance where we determined with high confidence that the reported UAP was airborne clutter, specifically a deflating balloon, we currently lack sufficient information in our dataset to attribute incidents to specific explanations. Airborne Clutter: These objects include birds, balloons, recreational unmanned aerial vehicles (UAV), or airborne debris like plastic bags that muddle a scene and affect an operator’s ability to identify true targets, such as enemy aircraft.
Natural Atmospheric Phenomena: Natural atmospheric phenomena includes ice crystals, moisture, and thermal fluctuations that may register on some infrared and radar systems. USG or Industry Developmental Programs: Some UAP observations could be attributable to developments and classified programs by U.S. entities. We were unable to confirm, however, that these systems accounted for any of the UAP reports we collected.
Foreign Adversary Systems: Some UAP may be technologies deployed by China, Russia, another nation, or a non-governmental entity.
Other: Although most of the UAP described in our dataset probably remain unidentified due to limited data or challenges to collection processing or analysis, we may require additional scientific knowledge to successfully collect on, analyze and characterize some of them. We would group such objects in this category pending scientific advances that allowed us to better understand them. The UAPTF intends to focus additional analysis on the small number of cases where a UAP appeared to display unusual flight characteristics or signature management.
UAP THREATEN FLIGHT SAFETY AND, POSSIBLY, NATIONAL SECURITY. UAP pose a hazard to safety of flight and could pose a broader danger if some instances represent sophisticated collection against U.S. military activities by a foreign government or demonstrate a breakthrough aerospace technology by a potential adversary.
Ongoing Airspace Concerns. When aviators encounter safety hazards, they are required to report these concerns. Depending on the location, volume, and behavior of hazards during incursions on ranges, pilots may cease their tests and/or training and land their aircraft, which has a deterrent effect on reporting. • The UAPTF has 11 reports of documented instances in which pilots reported near misses with a UAP.
Potential National Security Challenges. We currently lack data to indicate any UAP are part of a foreign collection program or indicative of a major technological advancement by a potential adversary. We continue to monitor for evidence of such programs given the counter intelligence challenge they would pose, particularly as some UAP have been detected near military facilities or by aircraft carrying the USG’s most advanced sensor systems.
EXPLAINING UAP WILL REQUIRE ANALYTIC, COLLECTION AND RESOURCE INVESTMENT.
Standardize the Reporting, Consolidate the Data, and Deepen the Analysis. In line with the provisions of Senate Report 116-233, accompanying the IAA for FY 2021, the UAPTF’s long-term goal is to widen the scope of its work to include additional UAP events documented by a broader swath of USG personnel and technical systems in its analysis. As the dataset increases, the UAPTF’s ability to employ data analytics to detect trends will also improve. The initial focus will be to employ artificial intelligence/machine learning algorithms to cluster and recognize similarities and patterns in features of the data points. As the database accumulates information from known aerial objects such as weather balloons, high-altitude or super-pressure balloons, and wildlife, machine learning can add efficiency by pre-assessing UAP reports to see if those records match similar events already in the database.
• The UAPTF has begun to develop interagency analytical and processing workflows
The majority of UAP data is from U.S. Navy reporting, but efforts are underway to standardize incident reporting across U.S. military services and other government agencies to ensure all relevant data is captured with respect to particular incidents and any U.S. activities that might be relevant. The UAPTF is currently working to acquire additional reporting, including from the U.S. Air Force (USAF), and has begun receiving data from the Federal Aviation Administration (FAA).
• Although USAF data collection has been limited historically the USAF began a six-month pilot program in November 2020 to collect in the most likely areas to encounter UAP and is evaluating how to normalize future collection, reporting, and analysis across the entire Air Force.
• The FAA captures data related to UAP during the normal course of managing air traffic operations. The FAA generally ingests this data when pilots and other airspace users report unusual or unexpected events to the FAA’s Air Traffic Organization.
• In addition, the FAA continuously monitors its systems for anomalies, generating additional information that may be of use to the UAPTF. The FAA is able to isolate data of interest to the UAPTF and make it available. The FAA has a robust and effective outreach program that can help the UAPTF reach members of the aviation community to highlight the importance of reporting UAP.
Expand Collection. The UAPTF is looking for novel ways to increase collection of UAP cluster areas when U.S. forces are not present as a way to baseline “standard” UAP activity and mitigate the collection bias in the dataset. One proposal is to use advanced algorithms to search historical data captured and stored by radars. The UAPTF also plans to update its current interagency UAP collection strategy in order bring to bear relevant collection platforms and methods from the DoD and the IC.
Increase Investment in Research and Development. The UAPTF has indicated that additional funding for research and development could further the future study of the topics laid out in this report. Such investments should be guided by a UAP Collection Strategy, UAP R&D Technical Roadmap, and a UAP Program Plan.
APPENDIX A – Definition of Key Terms This report and UAPTF databases use the following defining terms: Unidentified Aerial Phenomena (UAP): Airborne objects not immediately identifiable. The acronym UAP represents the broadest category of airborne objects reviewed for analysis. UAP Event: A holistic description of an occurrence during which a pilot or aircrew witnessed (or detected) a UAP.
UAP Incident: A specific part of the event. UAP Report: Documentation of a UAP event, to include verified chains of custody and basic information such as the time, date, location, and description of the UAP. UAP reports include Range Fouler 1 reports and other reporting.
1 U.S. Navy aviators define a “range fouler” as an activity or object that interrupts pre-planned training or other military activity in a military operating area or restricted airspace.
APPENDIX B – Senate Report Accompanying the Intelligence Authorization Act for Fiscal Year 2021 Senate Report 116-233, accompanying the Intelligence Authorization Act for Fiscal Year 2021, provides that the DNI, in consultation with the SECDEF and other relevant heads of USG Agencies, is to submit an intelligence assessment of the threat posed by UAP and the progress the UAPTF has made to understand this threat.
The Senate Report specifically requested that the report include:
A detailed analysis of UAP data and intelligence reporting collected or held by the Office of Naval Intelligence, including data and intelligence reporting held by the UAPTF;
A detailed analysis of unidentified phenomena data collected by: a. Geospatial Intelligence; b. Signals Intelligence; c. Human Intelligence; and d. Measurement and Signatures Intelligence
A detailed analysis of data of the Federal Bureau of Investigation, which was derived from investigations of intrusions of UAP data over restricted U.S. airspace; A detailed description of an interagency process for ensuring timely data collection and centralized analysis of all UAP reporting for the Federal Government, regardless of which service or agency acquired the information;
Identification of an official accountable for the process described in paragraph 4;
Identification of potential aerospace or other threats posed by the UAP to national security, and an assessment of whether this UAP activity may be attributed to one or more foreign adversaries;
Identification of any incidents or patterns that indicate a potential adversary, have achieved breakthrough aerospace capabilities that could put U.S. strategic or conventional forces at risk; and
Recommendations regarding increased collection of data, enhanced research and development, additional funding, and other resources.
‘The Pentagon seems fairly certain that these aren’t Russian and not Chinese–So what are they?’
#space #Extraterrestrial #UFO #UAP #Unexplained
‘Tucker Carlson Tonight’ says Pentagon has covered up UFO information
Human beings have been wondering about unexplained lights in the night sky since the first neanderthal cooked an ocelot over a campfire and looked up. But in our age—the modern age—fascination with ufos began in the summer of 1947 when a man called Mac Brazel found something very weird on his ranch in Corona, New Mexico, about 85 miles northwest of Roswell.
Suspecting it might be debris from outer space, Brazel dutifully brought the pieces to a nearby military base. The next day, the base issued a press release confirming that the material was in fact from a “flying disc,” a flying saucer. News agencies around the world announced the shocking find—flying saucers!
Then, within hours, the U.S. military changed its assessment. Brigadier General Roger Ramey, commander of the Eighth Air Force, announced that in fact, the debris from outside Roswell was nothing more than a weather balloon. Not a big deal. Nothing extraordinary. Certainly nothing extraterrestrial. Was General Ramey telling the truth about that? He may well have been. It may have been a weather balloon. But that wasn’t the end of the story.
Over the past 75 years, the US military has gathered evidence on a remarkable number of puzzling aerial phenomena, most of which were definitely not weather balloons. Unexplained flying objects have buzzed US Military bases, missile sites, ships, aircraft, and submarines, often at speeds and in directions that seem to defy any known human technology. Video
The Pentagon has said next to nothing about any of this in public and instead has consistently covered it up. Virtually everything we know about UFOs comes from whistleblowers. By the time this show launched nearly five years ago, it was clear there was definitely something very odd going on in the skies above us.
UFOs were not some crackpot theory, cooked up on late-night radio. They were absolutely real.
The question was, what are they exactly? Over the years, several powerful political figures in Washington, including Senator Harry Reid of Nevada, have pushed the U.S. military to reveal what it knows about UFOs. But in every case, they’ve failed to dislodge that information.
Then, last year, Senator Marco Rubio of Florida inserted a demand for transparency into a federal appropriations bill. By the end of June 2021, the government was required to turn over its full assessment of UFOs. Just a few hours ago, that report finally came out—late on a Friday.Video
We’ve only seen the public version so far, but here’s what we can tell you: Government investigators seem sincerely baffled by what these things are. Today’s report analyzed 144 separate sightings of UFOs by the US military. But in only one case could the government explain what it was. It was a quote “large, deflating balloon.” The rest of the 143 remain a complete and total mystery. The most sophisticated military in the world has no idea what these things are or even how they move from place to place.
Some of these aircraft, the report says, “appeared to remain stationary in winds aloft, move against the wind, maneuver abruptly, or move at considerable speed, without discernable means of propulsion.”
So we do know that no government in the world possesses anything like this. No technology exists that we know of. The Pentagon seems fairly certain that these aren’t Russian and not Chinese. So what are they?
The report doesn’t say, it notes only the obvious. UFOs, “clearly pose a safety of flight issue and may pose a challenge to U.S. National security.”
This article is adapted from Tucker Carlson’s opening commentary on the June 25, 2021, edition of “Tucker Carlson Tonight.”
Reviewing our own species’ behavior suggests a cautious approach to contact with extraterrestrials.
#Aliens #UFO #UAP #Space
Social structure is enormously important in trying to predict how alien societies might behave, as discussed in Part 1 of this series. It determines whether a society’s actions will be dominated by cooperation or selfishness. And the range of possible behaviors is enormous, from altruism—individuals helping others at a cost to themselves, even if it means increasing the other’s chances of survival and reproduction—to cannibalism, where an individual increases its own chances of survival by consuming another individual of its own species as food.
The latter extreme, cannibalism, has recently been studied by a group led by Mike Boots from the University of California-Berkeley. The researchers used Indian moth larvae in their experiments and found that less selfish behavior evolved under living conditions that forced individuals to interact more frequently with siblings. It’s true that Nature allows for cannibalism under extreme circumstances, where some individuals are sacrificed so that the species can survive. But as the research by Boots shows, individuals are more reluctant to employ this extreme practice if they have more interactions with each other, such as sibling interactions.
Reluctant or not, we shouldn’t be too hard in judging the moth larvae, because cannibalism has now been documented in more than 1,000 different species, including humans. There have been cannibalistic human tribes in the past, and even today there are cases of cannibalistic behavior in individuals. Neanderthals, our closest hominid species, are believed to have practiced cannibalism. More disturbingly, in certain societies cannibalism has been used for ritual purposes. An especially shocking example is the Aztecs, who are believed to have used razor-sharp obsidian blades to slice open the chests of their victims and rip out their hearts, as a prelude to ritual cannibalism.
Of course, cannibalism isn’t humankind’s only bad behavior—there are plenty of other examples. In an unforgettable two-part episode of Star Trek: The Next Generation (“All Good Things”) humanity is put on trial by the Q continuum. The critical question: whether our species has evolved beyond its savage past.
Of course, other species on our planet have no qualms about such matters. Think about lions, where a new male taking over the pride kills the cubs of his predecessor. We might debate whether it’s ethical to kill individuals of one’s own species for food in extreme circumstances, but Nature doesn’t seem to have a problem with it if it’s advantageous for the survival of the species. (Nature does not seem to care about the individual at all, sorry).
I think the same biological laws would apply to aliens as well. A spacefaring extraterrestrial civilization would be expected to reside at the top of their food chain. The more technologically advanced they are, and the more power they have over their fellow species, the more damage they can do (compare a Stone Age axe with today’s nuclear bomb). That should make us cautious if and when we make contact with an advanced alien species. We won’t know ahead of time whether they have overcome a savage past. Humans certainly have not.
“Hiding is not really an option,” says Lisa Kaltenegger
#space #Extraterrestrial #UFO #UAP
Feeling like you are being watched? It could be from a lot farther away than you think.
Astronomers took a technique used to look for life on other planets and flipped it around — so instead of looking to see what’s out there, they tried to see what places could see us.
There’s a lot.
This illustration provided by the American Museum of Natural History depicts the planet Earth, center, with the Sun in the background. The line of spots across the center of the image indicates star systems which can see Earth as it goes in front of our Sun. (OpenSpace/American Museum of Natural History via AP)
Astronomers calculated that 1,715 stars in our galactic neighborhood — and hundreds of probable Earth-like planets circling those stars — have had an unobstructed view of Earth during human civilization, according to a study Wednesday in the journal Nature.
“When I look up at the sky, it looks a little bit friendlier because it’s like, maybe somebody is waving,” said study lead author Lisa Kaltenegger, director of the Carl Sagan Institute at Cornell University.
Even though some experts, including the late Stephen Hawking, warn against reaching out to aliens because they could harm us, Kaltenegger said it doesn’t matter. If those planets have advanced life, someone out there could conclude that there is life back here based on oxygen in our atmosphere, or by the radio waves from human sources that have swept over 75 of the closest stars on her list.
“Hiding is not really an option,” she said.
One way humans look for potentially habitable planets is by watching them as they cross in front of the star they are orbiting, which dims the stars’ light slightly. Kaltenegger and astrophysicist Jacqueline Faherty of the American Museum of Natural History used the European Space Agency’s Gaia space telescope to turn that around, looking to see what star systems could watch Earth as it passes in front of the sun.
They looked at the 331,312 stars within 326 light-years of Earth. One light-year is 5.9 trillion miles. The angle to see Earth pass in front of the sun is so small that only the 1,715 could see Earth at some point in the last 5,000 years, including 313 that no longer can see us because we’ve moved out of view.
Another 319 stars will be able to see Earth in the next 5,000 years, including a few star systems where scientists have already spotted Earth-like planets, prime candidates for contact. That brings the total to more than 2,000 star systems with an Earth view.
The closest star on Kaltenegger’s list is the red dwarf star Wolf 359, which is 7.9 light-years away. It’s been able to see us since the disco era of the mid 1970s.
Carnegie Institution for Science planetary scientist Alan Boss, who wasn’t part of the study, called it “provocative.” He said in addition to viewing Earth moving in front of the star, space telescopes nearby could spot us even if the cosmic geometry is wrong: “So intelligent civilizations who build space telescopes could be studying us right now.”
So why haven’t we heard from them?
It takes a long time for messages and life to travel between stars and civilizations might not last long. So between those two it’s enough to limit the chances for civilizations to exchange “emails and TikTok videos,” Boss said in his own email. “So we should not expect aliens to show up anytime soon.”
Or, Kaltenneger said, life in the cosmos, could just be rare.
What’s exciting about the study is that it tells scientists “where to point our instruments,” said outside astronomer Seth Shostak of the SETI Institute that searches for extraterrestrial intelligence. “You might know where to look for the aliens!”
Artwork depicting a Kuiper Belt Object far beyond Neptune. Credit: ASA/ESA/G. Bacon (STScI)
While scanning older data from a telescopic survey of the sky, astronomers discovered a very interesting object: Called 2014 UN271, it’s a giant chunk of ice and rock that normally spends its time far, far out past Neptune, but is now heading into the solar system, and will get about as close to the Sun as Saturn over the next ten years!
To be clear, a lot of new comets we find dip pretty close to the Sun after spending millennia out there in the black, but this one is different for quite a few reasons.
One is how ridiculously elongated its orbit is: It goes from about 1.6 billion kilometers from the Sun (just outside Saturn’s orbit*) to a mind-numbing 2 trillion kilometers out. That’s a fifth of a light year! From that distance the Sun’s gravity is so weak a whisper could push this thing into interstellar space.
Another is its size. A big comet might be 50 kilometers wide (the size of the famous Hale-Bopp comet which visited the inner solar system in the 1990s). This one may be — and I’m still reeling from this — a staggering 200 kilometers wide.
Holy wow!Zoom In
The orbit and current position (in 2021) of the newly discovered megacomet 2014 UN271. The orbit is tipped over 90° to the plane of the planets, and it gets about as close to the Sun as Saturn. Credit: NASA/JPL-Caltech
2014 UN271 was found in data from the Dark Energy Survey, an enormous project to map about 1/8th of the entire sky over several years. The main mission of the survey is to map out hundreds of millions of galaxies and thousands of supernovae to understand better the shape, size, and expansion of the Universe.
However, it can also see some things significantly closer to home, like solar system bodies. These move very slowly from one night to the next, and software can be written to look at images taken at different times to search for moving objects. The first known image of 2014 UN271 was in 2014, so it was back-named to that date.
Pedro Bernardinelli, one of the astronomers on the team, posted this image of it, a combination of several images taken over years.
[His comment in the tweet is that no outgassing is seen from it yet; more on this below.]
2014 UN271 is what we call a Trans-Neptunian Object, or TNO. This is a class of objects that orbit the Sun out past Neptune, and come in a variety of shapes, sizes, orbits, and so on. Some are quite big. Pluto is technically the largest we know of, at about 2,400 km wide (the distance from Denver to Washington, D.C.). Many found are in the 100 – 1,000 km range, but these objects are so far away we’ve only found a handful of the trillions of them that are out there.Zoom In
A wider view of the orbit of 2014 UN271, showing it compared to the orbit of Neptune. Its orbit stretches roughly two trillion kilometers out from the Sun, but gets as close as about 1.6 billion. The position marked is where it will be in the year 2200. Credit: NASA/JPL-Caltech
2014 UN271 spends most of its 600,000-year or so orbit hundreds of billions of kilometers from the Sun, and the only reason it was found at all is because it’s only about 3 billion km away from us right now, roughly the distance of Neptune from the Sun. That’s how its size was found as well. For a given brightness we see at Earth, a shiny object is smaller and a dark one bigger. If we assume it reflects 4% of the sunlight hitting it (reasonable, since that’s a decent average for TNOs) it’s 200 kilometers wide. But it might be darker and bigger, or more reflective and smaller. We’ll know better in the next few years.
We don’t know what this object is made of exactly, but given what we know about TNOs, it’s likely a mix of water ice and rock, plus other frozen things like carbon dioxide, methane, nitrogen, and the like. It’s too small to be round; its gravity’s too weak to crush itself into a sphere (the smallest known object like that in the solar system is Saturn’s moon Mimas, at 400 km wide), so it’s very likely irregular in shape.Zoom In
Given its size, if it does start to get busy, it might get much brighter. Without activity it should get to about magnitude 18 at closest approach, which is still 1/100,000th as bright as the faintest star you can see by eye. It’ll take big telescopes to see it. But if it gets active, well, we’ll see.
And I wonder: It makes its closest approach in early 2031. That’s soon, but perhaps enough time to get a probe together to send to it. The European Space Agency is building a mission called Comet Interceptor that is specifically designed to look for comets coming from deep space that are on their first inbound trip to the inner solar system (like Comet Borisov from 2019). This one has dipped down many times over the past few billion years, but I wonder if ESA will make an exception for it? We’ve never had a chance to see anything like this up close before. Some moons of the outer planets look like captured TNOs, but they’ve certainly been altered over the eons by their host planet and proximity to the Sun. Seeing a new TNO this size up close and for an extended visit would be extraordinary.
I expect we’ll get lots of images of it soon (at the moment, unfortunately, Hubble is off-line, so hopefully the bigger ground-based ‘scopes can get a look). They’ll just be dots, even when it gets closer over the next decade, but there’s a lot we can learn from a dot. Stay tuned!
Zeroing in on the best environmental niches to explore during the next mission to Mars.
The Atacama Desert is one of the driest places on Earth, and is often used as an analog for Mars due to climatic and geochemical similarities between the two. In a new publication, an international group of researchers, led by me, report on our analysis of “islands of habitability” within the Atacama. We focused on rock types thought to host microorganisms best adapted to withstand a Mars-like environment—that is, characterized by extreme dryness, high ultraviolet irradiation, and scarcity of potential nutrients. That led us to zero in on three types: quartz rocks, gypsum crusts, and salt nodules surrounded by loose desert sediments.
Our approach employed a state-of-the-art methodology, including metagenomics and molecular separation techniques that are able to distinguish between DNA and ATP inside cells from those that exist outside. If we find them inside, it’s interpreted as coming from active, living cells.
Applying this technique, we found that cyanobacteria on the underside of quartz rocks were continuously active and even reproducing, while the microbial communities populating gypsum crusts and salt rocks have a lifestyle that switches between dormant and active phases.
Microbes living in the driest part of the Atacama, where it rains maybe once a decade, have amazing adaptation techniques. Called endoliths, they live within rocks, where they are protected from UV radiation, extreme temperature fluctuations, and the desiccating desert winds. Endoliths use salt from the rocks to draw life-sustaining water directly from the atmosphere (by the same principle that causes the salt in your shaker to clump up when exposed to air). That means these primitive life forms can survive where there is no precipitation.
Our team is not the only one searching for islands of life in an otherwise barren desert. Last year another group of researchers led by Armando Azua-Bustos from the Centro de Astrobiología in Madrid, Spain discovered a one-foot-deep layer of wet clay that hosts at least 30 different active microbial species. If such a habitat exists on Mars, ESA’s Rosaland Franklin rover, due to arrive there in June 2023, may be able to reach it with its drill.
Add to this the recent finding of volcanic activity on Mars that may have occurred within the last 50,000 years—a blink of an eye in geological terms—and we might have another potential habitat on Mars. To me it appears more and more likely that active hydrothermal areas are still existing on Mars. That would mean there are several potential hotspots for microbial life. We should identify and prioritize these, and send our next mission to explore at least one of them. That would certainly increase our chances of finding life.
The mysterious UFO had reportedly been hovering for some time before it instantly disappeared
The UFO resembling a “white Tic Tac” spotted in 2004 by Former U.S. Navy pilot Cmdr. David Fravor while on duty at the USS Nimitz is back – but this time it’s floating over England.
Pictures of the notorious UFO were snapped by Lucy Jane Castle, from Hinckley in south-west Leicestershire, who managed to grab a snap of the unexplained object and posted it on a UFO hunter’s Facebook page, which was found by the Daily Star.
“It was hovering for a while and within a blink of an eye it had gone,” Castle said.
UFO seen in clip released by Department of Defense. A Pentagon watchdog is launching a probe into the actions taken by the Department of Defense after a series of UFO sightings in recent years. (Department of Defense)
“Never seen anything like this before in that shape… Quickly took a picture while it was very still and within a blink of an eye it disappeared.”
Dan Watson, a fellow of the private UK UFO Sightings group, then posted a pic of two similar objects he claims to have seen over Swindon last year and a man called Terry Moore noted: “Sightings have Increased massively..from what I’ve heard US military had 6000 sightings last year alone..so either we’re being visited or someone has some new tech.”
In a 2017 interview, Fravor, who was on a routine training mission about 60 to 100 miles off the coast between San Diego and Ensenada, Mexico, described his initial sighting as a “white Tic Tac, about the same size as a Hornet, 40 feet long with no wings… Just hanging close to the water.”
The object didn’t create rotor wash — air turbulence caused by helicopter blades — and mirrored the pilots’ movements as they got closer, then disappeared altogether.
The retired Navy man spoke out after the Pentagon confirmed that a top-secret initiative called the Advanced Aerospace Threat Identification Program studied UFOs between 2007 and 2012 with a budget of $22 million.
Hybrid airships combine features of both traditional lighter-than-air airships and aeroplanes, which are heavier than air and achieve lift via aerodynamic wings and powerful engines.
As a result, they are slower than aeroplanes but consume significantly less energy.
The hybrid Airlander 10 features a passenger cabin suspended beneath an aerodynamic, helium-filled balloon. This provides 60 per cent of its lift, with the remainder coming from the passage of air over the hull.
It is powered by four vectored engines, which can swivel to provide lift when taking off and forward thrush when in flight.
“Using lighter-than-air technology means that Airlander 10 requires significantly less power to generate lift and fly,” a spokesperson for HAV told Dezeen.
“Airlander 10, therefore, produces far fewer emissions even before electrification.”
Hydrogen fuel cells convert the gas into electrical energy via a chemical reaction rather than by burning it. They are being touted as a potential way of decarbonising air travel since the only emission is water.
HAV calculates that a passenger’s individual carbon impact for a flight between Barcelona and Palma de Mallorca would be 4.5 kilograms on an Airlander 10, versus 53 kilograms taking the same trip on a traditional aeroplane.
Although airships are slower than traditional fixed-wing aeroplanes, HAV pointed out that they can deliver passengers closer to their final destination as they can take off and land on any flat surface, including water.
“Over shorter routes, this is balanced by Airlander 10’s ability to operate much closer to the final destination and fly point-to-point,” said HAV.
“In some cases, this makes the total journal time very similar or only slightly longer but with all the benefits of comfortable travel with very low emissions.”
Helium is the second-most abundant element in the universe after hydrogen, but it is a finite resource because it is light enough to escape the earth’s gravitational pull and float away into space.
The only non-renewable element on Earth, helium is a byproduct of the decay of radioactive elements including uranium and thorium.
Recently there have been fears that supplies of the gas are running out. However, HAV claims that Airlander 10 would not significantly deplete the planet’s resources.
“Although helium is a finite resource, there are ample reserves and new helium fields are being identified now,” said the company.
“Even with 600 aircraft in use in the world, Airlander 10s would make up just 1 per cent of the world’s annual helium consumption.”
HAV is partnering with British aviation business 2Excel Aviation to offer Airlander 10 to airlines and cruise companies.
“It is HAV’s plan to produce at least 12 aircraft per year,” said the company.
A leading expert on planetary astronomy reflects on what the next generation of space telescopes might reveal.
When I look up at the stars, I love to wonder what kind of planets might be around each one. Every star is a sun, and astronomers have found thousands of planets orbiting other stars, called exoplanets. Perhaps there are intelligent beings on a distant planet, looking back at our sun—a star to them—wondering the same thing.
We astronomers are unabashedly anticipating a paradigm shift in exoplanet characterization—made possible by a sophisticated new telescope over 30 years in the making: the James Webb Space Telescope, set for launch this October. Webb will undergo a series of daunting deployments, including the unfurling of a tennis court-sized, five-layer sunshield before reaching its destination a million miles away from Earth. Thousands of astronomers all around the world have pinned their research hopes and dreams on Webb, not just for exoplanets but for many frontier topics in astronomy. But for those of us studying exoplanets, Webb will open a new window.
Webb will bring us our first chance to routinely observe small rocky exoplanet atmospheres. Atmospheric water vapor would indicate the presence of surface liquid water oceans—key because a liquid solvent is needed for life. Imagine: Soon we may know that rocky planets with liquid water exist and are common—implying that habitable worlds might be all around us. Even more compelling is the chance to identify atmospheric gases that might be attributed to life, called biosignature gases. For example, molecular oxygen fills Earth’s atmosphere to 20 percent by volume but is so highly reactive it should not be present at all, without continual replenishment—in this case, by plants and photosynthetic bacteria. If molecular oxygen appeared in the atmosphere of a small rocky exoplanet, we would likewise assume that some process is at work there to continually replenish it. Admittedly, getting a strong robust signal from small exoplanet atmospheres might be tough for Webb, possibly right at the edge of its capabilities. True Earth twins—those Earth-size planets in Earth-like orbits about stars like our sun—are completely out of this telescope’s reach.
Instead, Webb’s ultimate lottery ticket is one of the handful of small planets transiting small red dwarf stars. Such planets orbiting in the “Goldilocks zone” will be different from Earth: locked into a rotation rate that causes a permanent day and permanent night side and bombarded by intense high-energy radiation from frequent stellar flares.
We may have already found a biosignature gas right next door, on our sister planet Venus. Venus, with its scorching surface so hot no life of any kind could survive, seems an unlikely abode. But a cloud-filled layer well above the surface does have a suitable temperature for life. The cloud environment is very harsh—highly acidic and incredibly dry—nonetheless, people have speculated about life in the Venus clouds for more than half a century.
I was part of a team led by Professor Jane Greaves that recently reported the detection of phosphine gas from radio telescope observations of Venus. We calculated that no known chemical process—from volcanoes to lightning to meteorite delivery and more—could produce phosphine in anywhere near the part-per-billion quantities inferred from our data. In addition, there simply is not enough hydrogen nor the right temperatures and pressures for phosphine (PH3) to form on its own. We are left with the possibility of unknown chemistry, or more speculatively, the possibility of life. On Earth, phosphine gas is associated only with life, produced by bacteria in oxygen-free environments such as wetlands and by humans for industry.
What followed our announcement was healthy, but unexpectedly harsh, skepticism from the scientific community. Some reanalyzed our data and did not find the signal. Others re-found the signal but attributed it to sulfur dioxide and not phosphine. Another team found independent evidence for phosphine in archived data taken directly in the Venus atmosphere by the 1978 NASA Pioneer Venus probe. Many scientists insisted the presence of phosphine can be explained by known chemistry, though no claims have yet been substantiated with scientific publications. The debate about phosphine gas on Venus will continue.
My exoplanet “finish line” has suddenly moved from a few years away to infinitely distanced. For even if we find a potential biosignature gas in an exoplanet atmosphere with Webb (or another of the planned or proposed next-generation telescopes), will the community agree that a tiny signal is more than noise in the data? If a robust signal is found, is there any way to associate the gas with life and not from chemistry in an unknown planetary environment? After all, we will have vastly less information for distant exoplanets as compared to up-close Venus, a planet with decades of observations and visits by over two dozen spacecraft.
Thankfully scientists have no shortage of imagination. Starshot is a project to launch thousands of tiny spacechips with four-meter-wide solar sails, accelerated to 20 percent the speed of light by a bank of coherent ground-based lasers with a combined power of gigawatts. After a 20-year journey to our nearest star system, Alpha Centauri, some of the surviving and still rapidly traveling starchips will take and send images of any planets back to Earth. An equally ambitious concept envisions a spacecraft 50 billion miles away from Earth, perfectly lined up with the sun and a distant exoplanet. The telescope can then use the sun as a powerful gravitational lens to magnify the exoplanet so highly that the planet surface could be imaged at a resolution of 10 kilometers.
The discovery and characterization of exoplanets has come a long way in the millennia since humans have pondered the mysteries of the multitude of stars. We are lucky to be the first generation who will not just hope, but can truly explore the nearest stars for worlds that are habitable, and just maybe, inhabited.
MIT Professor Sara Seager’s research has introduced many foundational ideas to the field of exoplanets and is now focusesd on the search for the first Earth-like exoplanets and signs of life on them.
Members of the House Intelligence Committee received a hush-hush sneak preview inside a SCIF, or “sensitive compartmented information facility.”
Just in time for Independence Day.
Capitol Hill lawmakers said Wednesday that UFOs could pose a pressing threat to America’s national security, as the pols emerged from a highly classified briefing with Navy and FBI officials on the unexplained phenomena.
As for the existence of extraterrestrial life, the lawmakers largely left the secrets inside the surveillance-proof room, declining to tell reporters what they learned.
But some did voice concerns that the UFOs — which may be espionage assets controlled by America’s foreign adversaries, in a possible explanation just slightly less terrifying than the vanguard of an alien invasion — could pose a danger to national security.
“We take the issue of unexplained aerial phenomena seriously to the extent that we’re dealing with the safety and security of US military personnel or the national security interests of the United States, so we want to know what we’re dealing with,” said Rep. Sean Patrick Maloney (D-NY).
“I think it’s important to understand that there are legitimate questions involving the safety and security of our personnel, and in our operations and in our sensitive activities, and we all know that there’s [a] proliferation of technologies out there,” he continued. “We need to understand the space a little bit better.”
Added Rep. Val Demings (D-Fla.), “You know it’s always about our safety and security — our national security is [priority] number one — and so that’s really the area where we really focused on this morning.”
Rep. Adam Schiff (D-Calif.), the committee chairman, implied that the briefing was eye-opening, but also declined to get into specifics ahead of the release of a public report.
“It was an interesting briefing,” he said. “I did learn things that were certainly new to me. But I think I’m going to leave it at that.”Video
Rep. Andre Carson (R-Ill.), who has been heading efforts on the UFO inquiry, said Americans should expect an eventual public hearing on the report’s findings.
“We’re looking forward to having a public hearing at some point,” he said. “I mean, there’s some national security concerns that we want to take into consideration.”
Rep. Mike Quigley (D-Ill.) said that, if anything, the landmark report shows that UFOs are finally being taken seriously.
“The stigma is gone,” he said. “Now that’s as big a change in policy as I’ve witnessed about this issue in my lifetime. So the fact that they are taking this sort of thing seriously for the first time, I think, is important.”
Referencing the 1997 sci-fi flick “Contact” — adapted from a Carl Sagan novel — Quigley admitted that the report won’t have all the answers and that some things remain unexplainable.
“What do they say in ‘Contact’? Occam’s razor,” he said. “I still think that’s what’s real, and there are things we can’t explain.”
But with so many mysteries of the universe still beyond human understanding, Quigley cautioned Americans against getting their hopes up for the report.
“If I had to predict how the public will react to this, one word would be ‘disappointing,'” he said.
Added a clearly unimpressed Rep. Peter Welch (D-Vt.), “I’m not on the edge of my seat.”
The mysterious dark vacuum of interstellar space is finally being revealed by two intrepid spacecraft that have become the first human-made objects to leave our Solar System.T
To mark the end of a turbulent year, we are bringing back some of our favourite stories for BBC Future’s “Best of 2020” collection.
Far from the protective embrace of the Sun, the edge of our Solar System would seem to be a cold, empty, and dark place. The yawning space between us and the nearest stars was for a long time thought to be a frighteningly vast expanse of nothingness.
Until recently, it was somewhere that humankind could only peer into from afar. Astronomers paid it only passing attention, preferring instead to focus their telescopes on the glowing masses of our neighbouring stars, galaxies and nebula.
But two spacecraft, built and launched in 1970s, have for the past few years been beaming back our first glimpses from this strange region we call interstellar space. As the first man-made objects to leave our Solar System, they are venturing into uncharted territory, billions of miles from home. No other spacecraft have travelled as far.
Magnetic fields are fighting and pushing and tied up with each other. The image you should have is like the plunge pool under Niagara Falls – Michele Bannister
And they have revealed that beyond the boundaries of our solar system lies an invisible region of chaotic, frothing activity.
“When you look at different parts of the electromagnetic spectrum, that area of space is very different from the blackness we perceive with our eyes,” says Michele Bannister, an astronomer at the University of Canterbury in Christchurch, New Zealand, who studies the outer reaches of the Solar System. “Magnetic fields are fighting and pushing and tied up with each other. The image you should have is like the plunge pool under Niagara Falls.”
Explosions like supernova fling cosmic rays out in all directions into interstellar space (Credit: Nasa/Hubble)
Instead of tumbling water, however, the turbulence is the result of the solar wind – a constant, powerful stream of charged particles, or plasma, spraying out in every direction from the Sun – as it crashes into a cocktail of gas, dust, and cosmic rays that blows between star systems, known as the “interstellar medium”.
Scientists have been building up a picture of what the interstellar medium is made of over the past century, thanks largely to observations with radio and X-ray telescopes. They have revealed it is composed of extremely diffuse ionised hydrogen atoms, dust, and cosmic rays interspersed with dense molecular clouds of gas thought to be the birthplace of new stars.
But its exact nature just outside our solar system has been largely a mystery, principally because the Sun, all eight planets and a distant disc of debris known as the Kuiper Belt, are all contained within a giant protective bubble formed by the solar wind, known as the heliosphere. As the Sun and its surrounding planets hurtle through the galaxy, this bubble buffets against the interstellar medium like an invisible shield, keeping out the majority of harmful cosmic rays and other material.
The size and shape of the heliosphere bubble alters as we pass through different regions of the interstellar medium
But its life-saving properties also make it more difficult to study what lies beyond the bubble. Even determining its size and shape is difficult from within.
“It’s like you’re inside your home and you want to know what it looks like. You have to go outside and take a look to really tell,” says Elena Provornikova, a postdoctoral researcher at the Johns Hopkins University Applied Physics Laboratory. “The only way to get an idea is to travel far away from the Sun, look back, and take an image from outside the heliosphere.”
This is no simple task. Compared to the whole of the Milky Way, our Solar System looks smaller than a grain of rice floating in the middle of the Pacific. And yet, the outer edge of the heliosphere is still so distant that it took more than 40 years for the Voyager 1 and Voyager 2 spacecraft to reach it as they flew from Earth.
The car-sized Voyager spacecraft were launched in 1977 and are now beaming back data from interstellar space (Credit: Nasa/JPL-Caltech)
What these two aging probes revealed about the boundary between the heliosphere and the interstellar medium has provided fresh clues about how our Solar System formed, and how life on Earth is even possible. Far from being a distinct boundary, the very edge of our Solar System actually churns with roiling magnetic fields, clashing stellar windstorms, storms of high energy particles and swirling radiation.
The size and shape of the heliosphere bubble alters as the Sun’s output changes, and as we pass through different regions of the interstellar medium. When the solar wind rises or falls, it changes the outward pressure on the bubble.
In 2014, the Sun’s activity surged, sending what amounted to a solar-wind hurricane sweeping out into space. The blast quickly washed over Mercury and Venus at close to 800 km per second (497 miles per second). After two days and 150 million km (93.2 million miles), it enveloped Earth. Fortunately, our planet’s magnetic field shielded us from its powerful, damaging radiation.
The gust pushed past Mars a day later and carried on through the asteroid belt toward the distant gas giants – Jupiter, Saturn, Uranus and after more than two months, Neptune, which orbits nearly 4.5 billion km (2.8 billion miles) from the Sun.
The heliosphere is unexpectedly large, which suggests that the interstellar medium in this part of the galaxy is less dense than people thought
After more than six months, the wind finally reached a point more than 13 billion km (8.1 billion miles) from the Sun known as the “termination shock”. Here, the Sun’s magnetic field, which propels the solar wind, becomes weak enough for interstellar medium to push against it.
The solar wind gust emerged from the termination shock traveling at less than half its previous speed – the hurricane downgraded to a tropical storm. Then in late 2015, it overtook the irregularly shaped form of Voyager 2, which is about the size of a small car. The plasma surge was detected by Voyager’s 40-year-old sensing technologies, powered by a slowly decaying plutonium battery.
The probe beamed data back toward Earth, which even at the speed of light took 18 hours to reach us. Astronomers could only receive Voyager’s information thanks to a massive array of 70-metre satellite dishes and advanced technology that hadn’t been imagined, let alone invented, when the probe left Earth in 1977.
The Sun produces a constant barrage of high energy particles known as the solar wind, which can rise and fall with the activity of our star (Credit: Nasa)
The solar wind surge reached Voyager 2 while it was still just inside our Solar System. A little more than a year later, the last gasps of the dying wind reached Voyager 1, which had crossed over into interstellar space in 2012.
The different routes taken by the two probes meant one was about 30 degrees above the solar plane, the other the same amount below. The solar wind burst reached them in different regions at different times, which provided useful clues about the nature of the heliopause.
The heliosphere is also unexpectedly large, which suggests that the interstellar medium in this part of the galaxy is less dense than people thought. The Sun cuts a path through interstellar space like a boat moving through water, creating a “bow wave” and stretching a wake out behind it, possibly with a tail (or tails) in shapes similar to those of comets. Both Voyagers exited through the “nose” of the heliosphere, and so provided no information about the tail.
“The estimate from the Voyagers is that the heliopause is about one astronomical unit thick (93 million miles, which is the average distance between the Earth and the Sun),” says Provornikova. “It’s not really a surface. It’s a region with complex processes. And we don’t know what’s going on there.”
A portion of the interstellar medium becomes converted to solar wind, actually increasing the outward push of the bubble
Not only do solar and interstellar winds create a turbulent tug of war in the boundary region, but particles appear to swap charges and momentum. As a result, a portion of the interstellar medium becomes converted to solar wind, actually increasing the outward push of the bubble.
And while a solar wind surge can provide interesting data, it seems to have a surprisingly small effect on the bubble’s overall size and shape. It appears that what happens outside the heliosphere matters much more than what happens within. The solar wind can wax or wane over time without appearing to dramatically affect the bubble. But if that bubble moves into a region of the galaxy with denser or less dense interstellar wind, then it will shrink or grow.
But many questions remain unanswered, including those around exactly how typical our protective solar-wind bubble might be.
The Sun’s heliosphere forms a long tail as it pushes its way through the interstellar medium on its journey around the galaxy (Credit: Nasa)
Provornikova says understanding more about our own heliosphere can tell us more about whether we’re alone in the universe.
“What we study in our own system will tell us about the conditions for the development of life in other stellar systems,” she says.
This is largely because by keeping the interstellar medium at bay, the solar wind also keeps out a life-threatening bombardment of radiation and deadly high-energy particles – such as cosmic rays – from deep space. Cosmic rays are protons and atomic nuclei streaming through space at nearly the speed of light. They can be generated when stars explode, when galaxies collapse into black holes, and other cataclysmic cosmic events. The region outside our Solar System is thick with a steady rain of these high-speed subatomic particles, which would be powerful enough to cause deadly radiation poisoning on a less sheltered planet.
Our star’s gravity extends well beyond the heliosphere, holding in place a distant, sparse sphere of ice, dust, and space debris known as the Oort Cloud
“Voyager definitively said that 90% of this radiation gets filtered out by the Sun,” says Jamie Rankin, a heliophysics researcher at Princeton University, and the first person to write a PhD thesis based on the Voyagers’ interstellar data. “If we didn’t have the solar wind protecting us, I don’t know if we’d be alive.”
Three additional Nasa probes will soon join the Voyagers in interstellar space, although two have already run out of power and stopped returning data. These few tiny pinpricks in the giant boundary will only ever provide limited information on their own. Fortunately, more expansive observation can be done closer to home.
Nasa’s International Boundary Explorer (Ibex), a tiny satellite that has orbited Earth since 2008, detects particles called “energetic neutral atoms” that pass through the interstellar boundary. Ibex creates three dimensional maps of the interactions happening all around the edge of the heliosphere.
The Ibex mission has detected a ribbon of high energy atoms being reflected back from the edge of the heliosphere by the galactic magnetic field (Credit: Nasa)
“You can think of Ibex maps as sort of the ‘Doppler radar’ and the Voyagers as on-the-ground weather stations,” says Rankin. She has used data from Voyagers, Ibex, and other sources to analyse smaller surges in the solar wind, and is currently working on a paper based on the much larger blast that began in 2014. Already, the evidence shows that the heliosphere was shrinking when Voyager 1 passed the boundary, but was expanding again when Voyager 2 crossed over.
“It’s quite a dynamic boundary,” she says. “It’s pretty amazing that this discovery was captured in Ibex’s 3D maps, which enabled us to track the local responses from the Voyagers at the same time.”
Ibex has revealed just how dynamic the boundary can be. In its first year it detected a giant ribbon of energetic atoms snaking across the boundary that changed over time, with features appearing and disappearing as briefly as six months. The ribbon turns out to be a region at the nose of the heliosphere where solar wind particles bounce off the galactic magnetc field and are reflected back into the Solar System.
When Voyager 2 left the solar system it detected a dramatic spike in cosmic rays which the heliosphere protects us from (Credit: Nasa/JPL-Caltech/GSFC)
But there is a twist to the Voyager story. Although they have left the heliosphere, they are still within range of many of our Sun’s other influences. The Sun’s light, for instance, would be visible to the naked human eye from other stars. Our star’s gravity also extends well beyond the heliosphere, holding in place a distant, sparse sphere of ice, dust, and space debris known as the Oort Cloud.
Oort objects still orbit the Sun, despite floating far out in interstellar space. While some comets have orbits that reach all the way out to the Oort cloud, a region 186-930 billion miles (300-1,500 billion km) is generally considered too distant for us to send probes of our own.
These distant objects have barely changed since the Solar System began, and may hold keys to everything from how planets form to how likely life is to arise in our universe. And with each wave of new data, new mysteries and questions also emerge.
Voyager 1 crossed over into interstellar space in 2012 100 Astronomical Units from the Sun but it still has the vast Oort Cloud ahead of it (Credit: Nasa/JPL-Caltech)
Provornikova says there may be a blanket of hydrogen covering some or all of the heliosphere, whose effects have yet to be decoded. In addition, the heliosphere appears to be careening into an interstellar cloud of particles and dust left over from ancient cosmic events whose effects on the boundary – and on those of us who live within it – have not been predicted.
“It could change the dimensions of the heliosphere, it could change its shape,” says Provornikova. “It could have different temperatures, different magnetic fields, different ionisation and all these different parameters. It’s very exciting because it’s an area of many discoveries, and we know so little about this interaction between our star and the local galaxy.”
Whatever happens, two car-sized assortments of metal bolted to small parabolic dishes – the intrepid Voyager probes – will be our Solar System’s vanguard, revealing ever more about this strange and uncharted territory as we plough onwards through space.
Two novel demonstrations bring the backbone of the quantum internet, quantum repeaters, a little closer.
Physicists take steps toward a quantum internet with a new way to link light particles. (Image credit: MARK GARLICK/SCIENCE PHOTO LIBRARY via Getty Images)
When the precursor to today’s internet carried its first message in 1969, clunky but functional classical computers had already been around for decades. Now, physicists are designing the embryonic threads of a whole new internet for moving and manipulating a radically different type of information: the quantum bit, or “qubit.” And this time, they aren’t waiting for the corresponding computers to exist first.
Two teams have now demonstrated an ensemble of technologies essential to building the backbone of such a network — devices known as quantum repeaters. The researchers managed, for the first time, to use light particles to bind two crystals separated by tens of meters into a single quantum mechanical system and verify the connection in a simple way. The experiments foreshadow a future where institutions across the planet can take advantage of a bizarre type of connection called entanglement.
“This is for sure a new step for quantum repeater applications,” said Julien Laurat, a physicist at Sorbonne University in France, who was not involved in the research.
Storing light in matter
One pillar of quantum information technology is the qubit, which is a system (like a particle) that exists in a combination of two states known as “superposition.” The qubit’s rich behavior compared with that of a classical bit (which can exist only as a 0 or a 1) allows for new modes of computation, somewhat like how a six-sided die is suited to different games than a two-sided coin.
In the recent experiments, teams at the University of Science and Technology of China (USTC) and the Institute of Photonic Sciences (ICFO) in Spain used photons, or light particles, to create qubits. Past experiments have often stored information of photons in gas clouds controlled precisely with lasers, but the USTC and ICFO researchers have advanced a new type of “solid state” quantum hard drive: glass crystals filled, or “doped,” with ions of a rare-earth metal. The ions took the place of the gas in earlier experiments, and the glass held them in place.
“You can think of our doped crystals as pretty much being a frozen cloud,” said Samuele Grandi, an ICFO physicist who worked on one of the experiments.
When a photon enters the crystal, it crashes into the ions (which the researchers have carefully prepared to respond to the incoming particle) and transfers its energy to them. In that moment, the crystal is holding the photon’s qubit and serving as a quantum memory, a storage device for quantum information.
A spooky connection
The second pillar of quantum communication is an ethereal link called entanglement, in which two particles or groups of particles act as one system, even while separated by large distances. This phenomenon lies at the heart of a quantum internet, yoking quantum devices much as fiber-optic cables and radio waves connect classical computers. A quantum network could stretch as far as one can entangle quantum memories, and no farther.
The problem is that, unlike bits on a hard drive, the ironclad rules of quantum mechanics forbid the copying and relaying of qubits in a quantum memory (a property that helps make quantum messages theoretically hack-proof). To overcome this obstacle, researchers imagine daisy-chaining quantum memories together with repeaters. To someday entangle memories between Boston and Washington, D.C., for instance, one might entangle the Boston memory with a memory in a New York repeater, and the New York repeater with the Washington, D.C., memory.
Grandi and his collaborators have taken a notable step toward such a device. Their apparatus starts with two laser-like devices, one on each side, , either of which can produce a pair of entangled photons. Even this first step is a challenge, with each device having just a 1-in-1,000 chance of doing so.
But with persistence, eventually one device will fire off twin photons. One photon goes straight into a corresponding quantum memory (the doped glass), and the other races down a fiber-optic cable. Halfway between the two devices (and their memories), this photon runs into a beam splitter — a material that lets the photon through half of the time.
That’s where the quantum magic happens. When Grandi and his collaborators see a photon pop out of the beam splitter, they have no idea if it came from the right side or the left side. Therefore they have no idea whether the partner photon is living in the memory on the right or the memory on the left. Quantum mechanics give this uncertainty a profound consequence. Since the stored photon could be residing in the right memory or in the left memory, it must exist in a superposition of right and left, both present and absent in both memories in a way that entangles the two crystals together.
“The fact that you cannot know which way it came [from],” Grandi said, “this is what generates the entanglement between the memories that are now holding one photon between them.”
When successful, the group’s apparatus stored one photon between two entangled memories in neighboring labs, 10 meters (33 feet) apart — an outcome frequently described mathematically in quantum textbooks but rarely experienced in the real world.
“This, for me, was mind-boggling,” Grandi told Live Science. “You know it works, but then you see it and this is really counterintuitive.”
Crucially, the team could easily confirm the surreal connection. A photon emerging from the beam splitter means the memories are entangled. Researchers call this particle a heralding photon because it “heralds” entanglement. Other physicists have entangled quantum memories of various types before, but the ICFO and USTC experiments were the first to entangle crystal memories with this clear signal of entanglement. Advertisement
The ICFO apparatus also used light of the same wavelength used in fiber-optic cables and proved that their memories could make multiple entanglement attempts at the same time — a step toward a quantum network carrying different messages simultaneously. The USTC group, in contrast, achieved a form of entanglement between two photons that is more immediately useful, although their connection was shorter lived. The teams described their work in twostudies published June 2 in the journal Nature.
These results “provide key important steps forward on building blocks of future quantum repeater chains,” Ronald Hanson, a quantum communications researcher at the Delft University of Technology in the Netherlands, told Live Science in an email. “For the field working on solid-state ensemble-based memories, these push the state of the art significantly.”
A long road ahead
The ICFO experiment represents the culmination of a decade of work spearheaded by physicist Hugues de Riedmatten to develop the procedures, materials and devices needed to create the heralded link. Grandi and his ICFO colleague Dario Lago-Rivera also went to extreme lengths to isolate the rudimentary repeater’s components from the turmoil of the world. If vibrations from the building or a blast of hot air caused the meters-long cable to stretch by even a dozen nanometers, for instance, the disturbance would ruin the experiment.
Despite the progress, practical quantum repeaters that can reliably entangle memories across cities — much less continents — remain years away. The ICFO memories can remember their qubits for only 25 microseconds, enough time to entangle with another memory no farther than 3 miles (5 kilometers) away. The finicky system is also unreliable, with attempts to write a photon to memory succeeding just 25% of the time.
Nevertheless, the researchers have various ideas for how to improve their setup. Buoyed by the success of combining so many quantum elements, they believe they’re on the path to stretching entanglement and quantum communications from neighboring labs to neighboring cities.
“This was a proof-of-principle starting point,” Grandi said. We just wanted to “see if everything works.”
NASA’s Mars Reconnaissance Orbiter spotted fresh impact of Meteorite Hit. The size of the New Crater on Mars is about 13 meters in diameter. The High-Resolution Imaging Science Experiment (Hi-RISE) camera aboard NASA’s Mars Reconnaissance Orbiter captured this new Crater on 12 March 2021.
Discovered crater may have bright ejecta from exposure of shallow subsurface materials, below a thin dark cover. An alternate theory—that this is a particle size effect—is unlikely because the bright materials are also distinctly redder than surrounding areas, and because ejecta is typically more coarse-grained, which would make the surface darker rather than brighter.
Pow! Mars Hit By Space Rocks 200 Times a Year!
One of many fresh impact craters spotted by the UA-led HiRISE camera, orbiting the Red Planet on board NASA’s Mars Reconnaissance Orbiter since 2006. (Image credit: Photo: NASA/JPL-Caltech/MSSS/UA)
Small space rocks are carving fresh craters into the Martian surface more often than previously thought, researchers say. A new study finds that there are more than 200 asteroid impacts on the Red Planet every year.
These asteroids and comet fragments are usually no bigger than 3 to 6 feet (1 to 2 meters) across — about 10 times smaller than the meteor that exploded over Chelyabinsk, Russia, in February. Small space rocks burn up in Earth’s atmosphere, never making it to the ground, but they can do damage on Mars because the planet has a much thinner atmosphere.
The holes gouged out by these asteroids are typically at least 12.8 feet (3.9 meters) wide, the researchers say. The 200-per-year space rockl impact rate for Mars was based on a portion of the 248 new Martian craters that have been identified in the past decade using images from the Mars Reconnaissance Orbiter, a NASA spacecraft that has been circling the Red Planet since 2006.
“It’s exciting to find these new craters right after they form,” study researcher Ingrid Daubar of the University of Arizona, Tucson, said in a statement. “It reminds you Mars is an active planet, and we can study processes that are happening today.”
The Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment (HiRISE) camera snapped amazingly detailed pictures of the fresh craters at sites where before-and-after images had been taken by the orbiter’s wider-view Context Camera and cameras on other orbiters studying the Red Planet, scientists said. The same method could be used to estimate the age of other recent features on the planet, including some that may be the result of Martian climate change.
The new calculation of Mars’ cratering rate dwarfs earlier estimates. Based on studies of lunar craters and moon rocks collected by NASA’s Apollo astronauts, scientists had calculated that there were just three to 10 yearly impacts on Mars.
“Mars now has the best-known current rate of cratering in the solar system,” said HiRISE principal investigator Alfred McEwen.
The research was detailed online this month in the journal Icarus.
The Giant Arc. Grey regions show areas that absorb magnesium, which reveals the distribution of galaxies and galaxy clusters. The blue dots show background quasars, or spotlights. (Image credit: Alexia Lopez/UCLan)
A newly discovered crescent of galaxies spanning 3.3 billion light–years is among the largest known structures in the universe and challenges some of astronomers’ most basic assumptions about the cosmos.
The epic arrangement, called the Giant Arc, consists of galaxies, galactic clusters, and lots of gas and dust. It is located 9.2 billion light-years away and stretches across roughly a 15th of the observable universe.
Its discovery was “serendipitous,” Alexia Lopez, a doctoral candidate in cosmology at the University of Central Lancashire (UCLan) in the U.K., told Live Science. Lopez was assembling maps of objects in the night sky using the light from about 120,000 quasars — distant bright cores of galaxies where supermassive black holes are consuming material and spewing out energy.
As this light passes through matter between us and the quasars, it is absorbed by different elements, leaving telltale traces that can give researchers important information. In particular, Lopez used marks left by magnesium to determine the distance to the intervening gas and dust, as well as the material’s position in the night sky.
In this way, the quasars act “like spotlights in a dark room, illuminating this intervening matter,” Lopez said.
In the midst of the cosmic maps, a structure began to emerge. “It was sort of a hint of a big arc,” Lopez said. “I remember going to Roger [Clowes] and saying ‘Oh, look at this.'”
Clowes, her doctoral adviser at UCLan, suggested further analysis to ensure it wasn’t some chance alignment or a trick of the data. After doing two different statistical tests, the researchers determined that there was less than a 0.0003% probability the Giant Arc wasn’t real. They presented their results on June 7 at the 238th virtual meeting of the American Astronomical Society.l
But the finding, which will take its place in the list of biggest things in the cosmos, undermines a bedrock expectation about the universe. Astronomers have long adhered to what’s known as the cosmological principle, which states that, at the largest scales, matter is more or less evenly distributed throughout space.
The Giant Arc bigger than other enormous assemblies, such as the Sloan Great Wall and the South Pole Wall, each of which are dwarfed by even larger cosmic features.
“There have been a number of large-scale structures discovered over the years,” Clowes told Live Science. “They’re so large, you wonder if they’re compatible with the cosmological principle.”
The fact that such colossal entities have clumped together in particular corners of the cosmos indicates that perhaps material isn’t distributed evenly around the universe.
But the current standard model of the universe is founded on the cosmological principle, Lopez added. “If we’re finding it not to be true, maybe we need to start looking at a different set of theories or rules.”
Lopez doesn’t know what those theories would look like, though she mentioned the idea of modifying how gravity works on the largest scales, a possibility that has been popular with a small but loud contingent of scientists in recent years.
Daniel Pomarède, a cosmographer at Paris-Saclay University in France who co-discovered the South Pole Wall, agreed that the cosmological principle should dictate a theoretical limit to the size of cosmic entities.
Some research has suggested that structures should reach a certain size and then be unable to get larger, Pomarède told Live Science. “Instead, we keep finding these bigger and bigger structures.”
Yet he isn’t quite ready to toss out the cosmological principle, which has been used in models of the universe for about a century. “It would be very bold to say that it will be replaced by something else,” he said.
Space is big — really big. And if you want to successfully navigate the interstellar depths of our Milky Way galaxy, you’re going to need some sort of reliable system. A new proposal tries to keep the method as simple as possible: use pairs of stars to provide a galactic reference frame.
Within our solar system, interplanetary spacecraft rely on Earth-based systems for navigation. When we send a radio signal to a spacecraft and it replies, we can use the time delay of the reply to calculate a distance. We can also monitor the spacecraft in the sky, and by combining all that information (position in the sky and distance from Earth), we can pinpoint the spacecraft’s location in the solar system and provide that information to the spacecraft itself.
We can also use the Doppler shift of those radio waves to estimate the speed at which the spacecraft is moving away from Earth. By using dishes scattered across our planet, we can measure the delay from a spacecraft’s signal reaching one dish versus another. When we combine that data with the position information, we have a complete six-dimensional lock on the spacecraft: its three dimensions of position and its three dimensions of velocity.
This method relies on a network of ground-based radar systems, all in constant communication with the spacecraft. The technique works for spacecraft within the solar system, and, just barely, NASA’s twin Voyager probes.
But any interstellar missions will need a new approach: They will have to navigate autonomously. In principle, these spacecraft could use onboard systems, like clocks and gyroscopes, but interstellar missions will last for decades at a minimum, and tiny errors and uncertainties in those onboard systems will undoubtedly cause those spacecraft to stray off course.
There’s also the option of using pulsars, rotating objects that appear to flicker, or pulsate, at regular intervals. Because each pulsar has a unique rotation period, these objects can serve as reliable beacons for deep-space missions. But this only works within a relatively small bubble near our solar system, because measurements of the rotation period can get contaminated by interstellar dust, and once you lose track of which pulsar is which, you’re lost.
The technique is based on a very old concept: parallax. If you stick your finger in front of your nose and alternate closing eyes, your finger will appear to wiggle. The change in its apparent position comes from the new viewpoint as you switch from eye to eye. If you do the same exercise while looking at a distant object, that object will appear to wiggle much less.
It was through parallax that scientists were first able to measure the distance to stars, and it’s through parallax that a spacecraft wandering far from home can get its bearings. Before launch, we load up the spacecraft with an accurate map of all the known stars in our galactic vicinity. Then, as the craft speeds away from the solar system, it measures the relative distances between multiple pairs of stars. As it moves, stars closer to the spacecraft appear to shift significantly, while more distant stars remain relatively fixed.
By measuring multiple pairs of stars and comparing the measurements with the original Earth-based catalog, the spacecraft can figure out which stars are which, and how far away it is from those stars, giving the spacecraft an accurate 3D position in the galaxy.
A relative effect
Getting the velocity of the spacecraft is a little trickier, and it relies on a weird quirk of special relativity. Because of the finiteness of the speed of light, if you’re moving quickly enough, objects can appear to be in different locations than they really are. Specifically, an object’s position will appear to be shifted in the direction of your motion. The effect is called aberration, and it’s measurable from Earth: As our planet orbits the sun, the stars appear to gently sway back and forth in the sky.
As long as the spacecraft is moving quickly enough (and if we want an interstellar mission to last decades, not millennia, it must), onboard systems will be able to measure this aberration. By noting which stars are shifted away from their expected position and by how much, the spacecraft can work out its 3D velocity.
Taken with the parallax measurements, the spacecraft can then recover its complete six-dimensional coordinates within the galaxy; it knows where it is and where it’s going.
How precise is this technique? According to the paper, if the spacecraft can measure the positions of just 20 stars to within 1 arc second of accuracy (an arc second is 1/60 of an arc minute, which itself is 1/60 of a degree), it can determine its position within the galaxy to an accuracy of 3 astronomical units (AU) and its velocity to within 2 kilometers per second (1.2 miles per second). One AU is equal to the average distance between Earth and the sun — roughly 93 million miles (150 million km) — so 3 AU is about 279 million miles (450 million km). That sounds like a lot, but it’s peanuts compared to the thousands of AU between stars.Advertisement
We have accurate positions to way more than 20 stars, so we could load up the spacecraft with a catalog of hundreds of millions of stars to use on its voyage. Each one the spacecraft can measure would help pinpoint its location with even more precision.
With the DART mission, scientists try to prepare for Earth’s worst catastrophe.
In March 1989, an asteroid measuring half a mile wide careened past Earth at 46,000 miles per hour. When it crossed Earth’s orbit, it was only 425,000 miles away—about twice the distance between Earth and the moon and an uncomfortably close shave for an object the size of a football field. If the asteroid had slammed into the planet, it would have punched a hole in Earth’s crust with the force of 20,000 hydrogen bombs, excavating a crater between five miles and 10 miles wide and a mile deep. Anything within a 40-mile radius would have been obliterated, and dust flowing into Earth’s atmosphere would have cooled regional temperatures enough to affect crop growth, causing localized food shortages. If it had slammed into the ocean instead, millions of people worldwide could have been killed by the ensuing tsunamis.
NASA officials deemed the flyby a close call. And, they noted, a larger asteroid would wreak even more havoc, from civilization-rending damage to a mass extinction snuffing out entire branches of life.
The asteroid was later formally named 4581 Asclepius, for the Greek god of healing and medicine. It led to a reckoning over how to safeguard the world from harm.
Shortly after the flyby—the closest approach by a large asteroid in a half-century—Congress tasked NASA with detecting and tracking asteroids that could pose a threat. By 2010, the agency had located 90 percent of all asteroids larger than one kilometer in diameter and is still working on finding 90 percent of all rocks wider than 140 meters across.
But protecting life on Earth will require more than seeing what’s coming. It will mean eliminating the asteroid headed our way—or at least pushing it aside.
This life-preserving mission is at the heart of DART, the Double Asteroid Redirection Test, a NASA mission being launched in November. Almost a year later, when it arrives at its destination seven million miles away, the dishwasher-size DART spacecraft will fling itself into a small asteroid, which is itself orbiting a larger asteroid. The spacecraft will be consigned to oblivion, and the small asteroidal moon will shift its orbit just enough to be detectable from Earth. Scientists hope to show that punching a distant asteroid is possible, in case we ever need to move one to avert disaster.
Every space mission is full of unknowns, but this one has more than its share, from the exact size and nature of the target asteroid pair to the potential change in the smaller one’s orbit, to the size and type of the crater DART will leave behind. The spacecraft will not even see its target until an hour before it crashes into it. But what DART will beam home in its final seconds will be priceless.
Neutralizing an asteroid threat sounds simple enough in theory. With enough warning, humans could strap a nuclear warhead to a rocket and destroy a threatening asteroid well before it hits Earth. At the least, the detonation could change the rock’s course just enough to protect the planet.
“But that makes people uncomfortable for all sorts of reasons,” says Andy Rivkin, DART’s co-lead investigator at the Applied Physics Laboratory of Johns Hopkins University.
Nuclear weapons as asteroid shields were first proposed in 1969, but many scientists eventually came to favor a so-called kinetic impactor as a safer alternative and one that would not violate any international treaties. In this scenario, a spacecraft would smack into an asteroid and change its course, setting the rock on a new path that does not meet up with Earth.
But asteroids are often unpredictable, and on every mission to visit one, there have been surprises. Asteroid Eros, which the NEAR spacecraft orbited and landed on in 1998, was covered in an unexpectedly large number of boulders. Bennu, which OSIRIS-REx gently tapped in 2020, was also boulder-filled and spewing particles and gas as it traveled through the void. Asteroids are so mysterious that scientists don’t know what will happen when they nudge one. DART’s primary goal is to find out.
In 2010, the U.S. National Academies of Science, Engineering, and Medicine recommended a practice impactor mission. Andy Cheng, who now serves as DART’s co-lead investigator, realized humanity needed two asteroids in order to analyze the impactor’s effect: The impactor would strike either a partner in a binary asteroid system or a moon orbiting an asteroid. Scientists could then observe the change in the struck body’s path around the other. This realization led to DART, and the mission was funded by 2012.
Cheng and colleagues quickly settled on an asteroid system called Didymos. The main asteroid was discovered in 1996, and its tiny moon, later named Dimorphos, was spotted in 2003. Scientists realized that the system will be closer to Earth next year than at any point in the next 50 years, which enables better Earth-based observation and tracking, Cheng says.
Hitting a moon instead of a larger main asteroid has plenty of benefits, says Rivkin. The Didymos-Dimorphos system is whizzing around the sun at 30 kilometers per second, and DART only packs a punch big enough to shift that speed by about one millimeter per second.
“In case of a real threat, that would be enough,” says Rivkin. “If you do that 10 or 20 years ahead of time, you miss the Earth.”
NASA’s congressionally mandated goal to find such threats means that we would probably have some warning; we already know the whereabouts of most deadly rocks, and scientists monitor their movement using networks of automated telescopes. Asteroid location data is fed into computer software to create a digital ephemeris, which provides the position and speed of objects in space and predicts their future orbital paths.
Building an asteroid deflector the next time it’s really needed will be a little easier after the practice the DART mission provides, Cheng notes. “NASA wants to show that they can do a mission like this quickly and not too expensively,” he says.
Consider an asteroid like 99942 Apophis, a 1,100-foot-wide asteroid that could kill tens of millions of people if it hit Earth. Recent observations show it will come close but won’t hit anytime in the next century. That’s just the type of target DART is meant as practice against, Cheng says.
“In the future, if we discover ‘Oh, my goodness, we were wrong. [Apophis] is going to hit the Earth,’ we would have enough time,” he says. How long a deflector would take to build depends on just how much time lies between when scientists recognize the threat and the predicted impact. “For something as big as Apophis, which has the potential to wipe out a small country, money becomes less of an object,” reasons Cheng.
Even with sufficient time to build and launch a do-or-die mission, to nudge a real potential killer like Asclepius out of the way would require far more heft than a DART-size spacecraft.
Luckily, DART is not designed to save the day. It is designed to find out what saving the day might look like. One comforting fact about its target, though, is that it is the same composition and roughly the same size as most deadly asteroids, according to Rivkin.
“It’s representative of the kind of material that is out there and [has most commonly hit] the Earth,” Rivkin says. Dimorphos is moving around Didymos at a few dozen centimeters per second. Understanding just how Didymos and Dimorphos travel through space is one of the DART imaging team’s goals, because the only way to judge the mission’s success is to be able to measure the change in the moon’s orbit.
DART’s targets are so far away that they cannot be seen directly, so scientists on Earth will detect any orbital change by measuring Didymos’ brightness. When the moon moves in front of the asteroid relative to our location on Earth, Didymos will dim ever so slightly. If it dims earlier or later than it should per the ephemeris, the DART team will know their mission was a success.
DART will carry an Italian cubesat called LICIA, which will separate from DART before impact and capture images of its mothership’s demise. In 2024, the European Space Agency (ESA) will launch a probe called Hera to map DART’s impact crater and measure the asteroid’s mass, another thing scientists don’t yet know.
Based on observations from the former Arecibo Observatory’s radio telescope, astronomers know Dimorphos is about 500 feet wide and orbits Didymos roughly every 12 hours. They know Didymos is made of the same material as the most common meteorites. But that’s about it.
“We have no clue what Dimorphos looks like,” says Elena Adams, a systems engineer at APL. “We have some size predictions, but we don’t know if it’s a dog-bone shape, an oblong thing like Eros, or a duck-looking thing like Comet 67/P in the Rosetta mission.”
DART won’t be able to see Dimorphos clearly until about four minutes before impact. Its camera has to aim at a single pixel, barely a crumb on your phone screen. Earth-based telescopes and radar and the DART’s onboard Didymos Reconnaissance and Asteroid Camera for OpNav (DRACO) will watch Didymos and Dimorphos in the months after launch but will only be able to guess at their exact location within a range of about 15 kilometers, Cheng says. Seven days before impact, the DART team will turn on a new guidance system, built using APL guided-missile technology, and enable the spacecraft to aim itself at Dimorphos. It will have to crash within 15 meters of its aim point. Letting the spacecraft guide itself is necessary, Cheng says. NASA’s commands—sent after spacecraft imagery had been received on Earth—would not arrive fast enough to tell the spacecraft where to hit.
Built Like a Tank
DART will also serve as a test bed for the next generation of space equipment. Space mission planners usually care about weight more than almost anything else—every gram sent aloft must be carefully weighed against the spacecraft’s fuel requirements, design parameters, and science goals. But because DART’s 670 kilograms don’t come close to maxing out the capability of the SpaceX Falcon 9 rocket that will loft it—it won’t take much mass to nudge the asteroid—DART’s engineers were able to throw on practically anything they wanted. Other asteroid-visiting missions have complex, heavy cameras and even asteroid sample-return equipment, but not DART.
“Mass is the most precious commodity you can ever have in space travel,” says Adams. “But on DART, we’re like, ‘Eh, we don’t worry about it.’ It is built like a tank.”
What’s more, DART doesn’t have to fly as fast as the Parker Solar Probe or other deep-space missions, which means the energy required to leave Earth is a little lower. The navigation system—SMARTNav, or Small-body Maneuvering Autonomous Real-Time Navigation—is critical for DART, which will not have any images of its target until moments before impact. With no advance images, all decisions need to be made on board, with no human at the joystick, explains Michelle Chen, who leads the SmartNav team at APL.
A typical new TV has 4K resolution, meaning its screen measures roughly 4,000 pixels horizontally. The DRACO camera has only 2K, and within that, the Didymos system—both asteroid and moon—occupies a single pixel, until the mission’s final hour.
“When we are looking at the asteroid, I always have to clean my monitor screen, because I’m never sure if it’s a dust speck or what,” Chen says.
The camera can’t resolve both objects separately until about an hour before impact. So SmartNav’s algorithm continually scrutinizes DRACO’s images, filtering out other objects and dust, to lock onto its target.
Chen has spent the past several years testing her algorithm to make sure it can handle any surprises. If DART arrives at Didymos and finds it has more than one moon, SmartNav will know what to do. It can handle unexpected lighting conditions—if the moon is opposite the sunlit side of the asteroid, for example, and therefore harder to spot. Even though SmartNav will not survive DART’s destruction, Chen says its breakthroughs will inform new systems for the next generation of spacecraft. This is possible only because DART has an ordinary central processing unit-powered computer as well as a field programmable gate array, or FPGA, which can handle specific tasks with great efficiency. The FPGA will allow DART to handle several tasks simultaneously, including streaming images to Earth in its final moments, processing those images for SmartNav to use to pilot the craft, and firing its hydrazine thrusters to adjust its trajectory.
The burden of ultimate success or failure rests on the shoulders of the mission design team, who must figure out the spacecraft’s approach geometry, make sure its antennas are pointed the right way to communicate with Earth, ensure that its prototype solar panels don’t wiggle the craft too much, and check that DRACO is pointing the right way to lock on to its target.
DART has two propulsion systems to make sure it is in the right place at the right time. Only one will be used for critical guidance and is a traditional spacecraft thruster system, with 12 small engines using the common rocket propellant hydrazine. But DART will also carry a new electric ion propulsion system called NEXT-C. This ion drive uses electricity harvested from DART’s enormous solar panels. They are unique among spacecraft but may be a game-changer for future probes because they’re so lightweight. The arrays are built of a flexible material, which unfurls after launch and stretches between two rigid booms on each side of DART. “You have this rolled-up thing that looks like a sausage, and then after launch, you actuate the mechanism and snap it open, like a snap bracelet,” Adams says.
The ion drive powered by the array works by knocking electrons free from a gas propellant to make ions. The positively charged gas is repelled by a negatively charged electric field. The ions are discharged from the engine, pushing the craft just as a typical exhaust would.
Though the ion drive won’t produce much thrust, it’s more than DART will need, says Justin Atchison, an engineer at APL. The real benefit is its ability to shift gears, as it were, through a wide range of power levels. It can use a range from 600 watts up to 7.5 kilowatts. It has a much wider throttle zone than other ion drives and is much more efficient than typical thruster systems.
“You can use the same thruster when you are near the sun and have high power or far from the sun and have low power,” Atchison says. This will enable future spacecraft to adjust their trajectories and velocities no matter where they are—even though the latter is not really an issue for DART.
When DART arrives, it will have very little time to assess its surroundings before it shatters to bits. Many months later, scientists on the ground will still be busy reconstructing its final moments, says Angela Stickle, a planetary scientist at APL whose specialty is hypervelocity impacts. Her simulations will help scientists understand what Dimorphos is like and maybe learn more about how binary asteroids form.
Although binary asteroids are common—they represent one in every six asteroids—scientists are still unsure about how they came to be. The asteroid’s moon might have calved off from Didymos at some point in the past, either through centrifugal forces or an impact with a different object. Or it’s possible that Didymos captured a small asteroid crumb that was itself calved from a larger object.
Stickle says she is eager to learn more about the moonlet, which will be possible by studying its change in trajectory after impact.
Although ESA’s Hera probe won’t arrive for a few years, the nature of DART’s demise will tell Stickle and her fellow scientists plenty about the rock that destroyed it. DART’s own imagery will show what Dimorphos looks like in the few seconds before impact, and the Italian cubesat, LICIA, will watch the ejecta. Then astronomers like Cristina Thomas, who works at Northern Arizona University and leads DART’s observation working group, will scrutinize the change in Dimorphos’ orbit. Thomas has applied for time on the James Webb Space Telescope to check Dimorphos’ new trajectory, and she is developing software that can pull tiny glimmers of light from telescope observations to see how the light changes. “We draw a circle around it, pull out all the light in that circle, and we can see these small changes,” she says. “If it was just you and me looking at it, you wouldn’t be able to see anything, but the computer can see.”
Stickle can plug all this data into her calculations and come up with new results on the nature of the asteroid. But the asteroid still might throw a wrench into everyone’s plans.
“I more worry that it’s going to be some crazy new asteroid structure that we’ve never seen before,” she says. “We did some experiments where we shot into cotton candy, and the whole thing just explodes. I don’t think that’s likely for an asteroid, but it could have a weird structural material property that we just didn’t predict. People are creative, but asteroids have proved us wrong in the past. And space is weird.”
“I thought, ‘I’m going to spend all these years doing something that’s literally going to puff up in smoke,’ ” Chen recalls. “But to me, it’s really a stepping stone.” Atchison says he likes the project’s finality. The mission has one, specific task, and the team will know without a doubt whether they pulled it off.
“That part is what keeps me up at night,” Atchison says. “Making sure we get it right the first time, because we don’t get a second time.”
That may be true for Earth too. We know a deadly strike from space has happened before. In 1989, geologists confirmed a massive crater off the coast of Mexico’s Yucatan Peninsula. Throughout rocks on Earth, scientists found layers awash in iridium, an element known to come from asteroids. The iridium spike matched the Cretaceous-Paleogene boundary—the demarcation of the downfall of the dinosaurs, in an extinction event that wiped out almost all life on Earth.
What came to be named the Chicxulub crater proved that space rocks can end the world. Now it’s up to DART to prove that spacecraft could, one day, save it.
“WE PROPOSE THAT THERE MAY BE A FOURTH DIMENSION THAT ONLY THE DARK FORCES KNOW ABOUT.”
#space #physics #darkmatter #unexplained
According to a team of researchers at the University of California, Riverside, an extra dimension in space-time could be hiding dark mater — the stuff that appears to make up 85 percent of the mass in the universe, yet remains undetectable by scientific equipment.
“We live in an ocean of dark matter, yet we know very little about what it could be,” said Flip Tanedo, assistant professor of physics and astronomy and the senior author of the paper published in the Journal of High Energy Physics, in a statement.
“Our observed universe has three dimensions of space,” he added. “We propose that there may be a fourth dimension that only the dark forces know about.”
Dark Matter Conundrum
Tanedo and his colleague’s theory could finally allow us to explain its existence.
“It is one of the most vexing known unknowns in nature,” Tanedo added. “We know it exists, but we do not know how to look for it or why it hasn’t shown up where we expected it.”
Despite scientists’ best efforts, dark matter has remained elusive. We still don’t know what it is made of or why it exists in the first place. We also aren’t able to observe it directly as it doesn’t absorb, reflect or emit any kind of electromagnetic radiation.
But according to Tanedo and his team’s theory, some invisible dark matter particles interact with other invisible particles in a way that causes these second particles to not behave like others — via an additional dimension.
“Over the past decade, physicists have come to appreciate that, in addition to dark matter, hidden dark forces may govern dark matter’s interactions,” Tanedo said. “These could completely rewrite the rules for how one ought to look for dark matter.
“The extra dimension can explain why dark matter has hidden so well from our attempts to study it in a lab,” he added.