The Japanese mission Hayabusa2 just bid farewell to the asteroid the probe spent a year and a half studying, and scientists have now announced some intriguing trends they noticed in the spacecraft’s photos.
Those trends had to do with the craters dotting the surface of the asteroid, dubbed Ryugu. The team used 340 different images of the space rock’s surface and identified a total of 77 craters scattered over Ryugu, each measuring at least 66 feet (20 meters) across. But those pockmarks aren’t distributed as evenly across the surface as the scientists might have expected, the researchers explained in a new paper.
Instead, the craters are clustered in a couple of different ways. There are more craters near the equator than the poles, the scientists found, and there are more on the eastern side of Ryugu than on the western. Additionally, the scientists didn’t find as many relatively smaller craters within this size range as they might have expected given the number of very large craters the space rock sports.
Those patterns became particularly clear when the team looked at particularly large craters, the 11 that measure at least 328 feet (100 m) across. (That collection includes Ryugu’s largest crater, Urashima, which is about one-third of the asteroid’s diameter.)
Of those 11 monster craters, five line up along the ridge ringing the asteroid’s equator. That’s more than twice as many as the team would have expected if Ryugu’s craters were distributed randomly, the researchers said.
The discrepancies don’t mean that the solar system has been targeting this one unremarkable space rock, of course. Instead, the team said that the clustering of craters is a result of the asteroid’s geological history.
The researchers said that most of the equatorial ridge is relatively old but the westernmost part is younger. That would explain why the craters are unevenly distributed: The rest of the ridge has had much more time to pick up these impact scars.
The scientists hope that when they analyze the samples from Ryugu now on their way back to Earth, it could better inform these theories about how the asteroid came to be the way it is now, a university statement about the project said. Those samples are due to land near the end of next year.
The research is described in a paper being published next spring in the journal Icarus.
For the very first time, scientists have found evidence of a giant planet associated with a white dwarf star.
Researchers used ESO’s Very Large Telescope to gain a stronger understanding of the properties of the star named WDJ0914+1914.
“It was one of those chance discoveries,” researcher and study lead Boris Gänsicke, from the University of Warwick in the United Kingdom, said in a statement.
The team’s follow-up observations, published in a new study in Nature, showed the presence of hydrogen, oxygen and sulphur associated with the white dwarf.
By analyzing the spectra taken by ESO’s X-shooter instrument, the team discovered that these elements were in a disc of gas swirling into the white dwarf, and not coming from the star itself.
This illustration shows the white dwarf WDJ0914+1914 and its Neptune-like exoplanet. (ESO/M. Kornmesser)
According to a press release detailing the study’s findings, the detected amounts of hydrogen, oxygen and sulphur are similar to those found in the deep atmospheric layers of cold, giant planets like Neptune and Uranus.
Scientists believe that if this type of planet was orbiting near a hot white dwarf, the extreme ultraviolet radiation from the star would strip away its outer layers, and some of this stripped gas would swirl into a disc, itself coming together onto the white dwarf.
And that is what researchers think they are observing around WDJ0914+1914: the first evaporating planet orbiting a white dwarf.
“It took a few weeks of very hard thinking to figure out that the only way to make such a disc is the evaporation of a giant planet,” Matthias Schreiber from the University of Valparaiso in Chile, who computed the past and future evolution of this system, said in a statement.
The European Space Agency has received approval to aid NASA in its asteroid deflection plan, the upcoming Double Asteroid Redirection Test (DART) mission.
According to the ESA’s website, the European space ministers have approved the agency’s plan to build and launch the Hera spacecraft, which will visit the Didymos asteroid system. NASA’s DART spacecraft is slated to collide with the smaller Didymoon asteroid, which orbits Didymos, sometime near the end of 2022.
Didymoon’s diameter is roughly 525 feet (160 meters), according to NASA, whereas the larger Didymos is approximately 2,560 feet wide. Both are considered “potentially hazardous” near-Earth objects.
An artist’s illustration of asteroids, or near-Earth objects, that highlight the need for a complete Space Situational Awareness system. (ESA – P.Carril)
“Potentially hazardous” NEOs are defined as space objects that come within 0.05 astronomical units and measure more than 460 feet in diameter, according to the U.S. space agency.
“Hera will be humanity’s first-ever spacecraft to visit a double asteroid, the Didymos binary system,” the ESA wrote on its website.
The ESA added: “Hera’s up-close observations will turn asteroid deflection into a well-understood planetary defense technique.” A video was also posted to the agency’s YouTube page providing more detail.
The current plan is for DART to launch aboard a SpaceX rocket in the middle of 2021, ultimately crashing into Didymoon toward the end of 2022. If successful, Hera would launch in 2024 and arrive by 2026 to inspect the findings. The ESA added Hera would “map the resulting impact crater and measure the asteroid’s mass.”
It will also have CubeSats on board that will be able to get closer to the asteroid’s surface, carry out studies and ultimately, touch down on its surface.
In April, NASA awarded a $69 million contract to SpaceX, the space exploration company led by Elon Musk, to help it with asteroid deflection via its DART mission. Separately that month, the ESA announced that it was developing a self-driving craft for Hera.
NASA has recently expanded its planetary defense protocols, including last year’s unveiling of a bold new plan to protect Earth.
Last June, NASA unveiled a 20-page plan that details the steps the U.S. should take to be better prepared for NEOs such as asteroids and comets that come within 30 million miles of the planet.
Lindley Johnson, NASA’s planetary defense officer, said at the time that the country “already has significant scientific, technical and operational capabilities” to help with NEOs, but implementing the new plan would “greatly increase our nation’s readiness and work with international partners to effectively respond should a new potential asteroid impact be detected.”
In addition to enhancing NEO detection, tracking and characterizing capabilities and improving modeling prediction, the plan also aims to develop technologies for deflecting NEOs, increasing international cooperation and establishing new NEO impact emergency procedures and action protocols.
Separately in April, NASA Administrator Jim Bridenstine said that an asteroid strike is not something to be taken lightly and is perhaps Earth’s biggest threat.
“We have to make sure that people understand that this is not about Hollywood, it’s not about movies,” Bridenstine said at the International Academy of Astronautics’ 2019 Planetary Defense Conference in College Park, Md., according to Space.com. “This is about ultimately protecting the only planet we know right now to host life, and that is the planet Earth.”
According to a 2018 report put together by Planetary.org, there are more than 18,000 NEOs.
NASA announced Monday that it had finally found the crash site of India’s lost lunar lander, Vikram. Images taken by the Lunar Reconnaissance Orbiter Camera show the lander’s crash site about 600 km (372 miles) from the Moon’s south pole, shown below, including an impact point and field of debris surrounding it.
The impact point. (NASA/Goddard/Arizona State University)
Vikram was part of India’s Chandrayaan-2 mission to send an orbiter, lander, and rover to the Moon’s surface. Those ambitions were cut short when the Indian Space Research Organization lost touch with the lander as it was approaching the lunar surface on September 7 after being released by the orbiter.
Two and a half months after the agency lost contact, the ISRO finally admitted the lander crashed – a week before NASA discovered the lander’s crash site.
The lander, with an orbiter and a rover called Pragyaan in tow, launched from the Satish Dhawan Space Centre, Sriharikota in Andhra Pradesh on July 15. The orbiter is currently in full operation.
The lander was set to make India only the fourth country after the US, the USSR, and China to softly land a manmade object on the Moon.
“Despite the loss, getting that close to the surface was an amazing achievement,” reads NASA’s statement.
99942 Apophis, previously known by its provisional designation 2004 MN4, is a 370-meter diameter near-Earth asteroid that caused a brief period of concern in December 2004 because initial observations indicated a probability of up to 2.7% that it would hit Earth on April 13, 2029. • Additional observations provided improved predictions that eliminated the possibility of an impact on Earth or the Moon in 2029. However, until 2006, a possibility remained that during the 2029 close encounter with Earth, Apophis would pass through a gravitational keyhole, a small region no more than about 0.5 mile wide, or 0.8 km that would set up a future impact exactly seven years later on April 13, 2036.
ASTEROID APOPHIS, the “God of Chaos” space rock capable of wiping out millions of people, has a slim chance of striking Earth on 10 different dates, space agency NASA has discovered.
The imposing Asteroid Apophis is the third biggest space rock currently tracked by NASA’s automated warning systems. NASA estimates Apophis measures around 1,214ft (370m) across, making it a potentially cataclysmic threat to Earth. A 2018 White House report on the dangers posed by asteroids found objects on this scale threaten “regional” to “continental” damage upon impact.
If Asteroid Apophis arrived in the skies over Earth today, the brute force of impact would likely kill untold millions of people.
In a bid to safeguard our planet from the doomsday scenario, NASA keeps a watchful eye on the asteroid’s trajectory.
As a result, the US space agency has determined 10 dates on which there is a calculable risk of deadly impact.
If Apophis ends up hitting the planet on any of these dates, NASA said the force of impact would be equivalent to 1,200 megatons or 1,200,000 kilotons of kinetic energy.
For comparison, the US atomic bomb dropped on Hiroshima in 1945 detonated with the force of around 15 kilotons of TNT.
When could Asteroid Apophis strike the Earth?
NASA predicts 10 dates between 2060 and 2103 on which there is a small chance Apophis will veer off its path and into Earth.
The dates are:
April 12, 2060
April 11, 2065
April 12, 2068
October 10, 2068
April 13, 2076
April 13, 2077
April 13, 2078
October 10, 2089
April 13, 2091
April 14, 2103
On any of these dates, NASA estimates the space rock would fly into our planet at speeds of about 5.85km per second or 13,086mph (21,060km/h).
At the point of atmospheric entry, the asteroid would then speed up to about 12.62km per second or 28,230mph (45,532km/h).
By observing Apophis during its 2029 flyby, we will gain important scientific knowledge
Paul Chodas, NASA Center for Near Earth Studies
According to NASA’s Sentry monitoring systems, Asteroid Apophis weighs an incredible 67,240,989 tons (6,100,0000,000kg).
Because of its colossal size, speed and closeness to Earth, Apophis has been officially dubbed by astronomers a Potentially Hazardous Asteroid or PHA.
The space rock was first discovered on June 19, 2004, and astronomers initially feared Apophis could hit Earth during a close flyby in 2029.
The possibility of impact was ruled out for that year but 10 more possible impact dates remain.
Will the Asteroid Apophis hit Earth on any of these dates?
Officially dubbed by astronomers 99942 Apophis or 2004 MN4, the giant space rock has been a keen object of study since its discovery 15 years ago.
Thankfully, NASA is yet to sound the alarm bells as there appears to be no significant risk of impact just yet.
In April 2060, there is a very small chance the space rock will divert its orbit straight into our home planet.
But the risk of impact is too small to lose any sleep over.
According to NASA, there are one-in-10 million odds of impact for that date.
In other words, there is a 0.000010 percent chance of impact or a 99.99999 chance the asteroid will miss.
There is a slightly higher chance of impact in 2065 with NASA giving the asteroid odds of about one-in-3.8 million.
The odds translate to a 0.000026 percent chance of impact or a 99.999974 chance the space rock will miss.
However, NASA’s overall odds off impact for the next 100 years are a much more terrifying one-in-110,000.
Asteroid Apophis: Four space rocks with a slim chance of hitting Earth in the foreseeable future (Image: GETTY/EXPRESS)
This means Apophis has a 0.00089 percent chance of striking the planet by the year 2103.
On April 13, 2029, the asteroid will make a close approach of our planet.
NASA’s asteroid expert Paul Chodas said: “Apophis is a representative of about 2,000 currently known Potentially Hazardous Asteroids.
“By observing Apophis during its 2029 flyby, we will gain important scientific knowledge that could one day be used for planetary defence.”
Asteroid could send world back to ‘dinosaur times’ says expert
According to the Planetary Society, you should not lose any sleep over the threat of asteroid impacts.
Although there is no object currently flying towards our planet, astronomers have devised potential timescales for future impacts based on past events.
On average, 100 tons of space debris and dust hits the planet’s atmosphere every single day.
About 30 “small asteroids a few meters in size” hit the planet once a year.
Larger space rocks hit even less frequently, from once every few hundreds of years to once every few thousand years.
The Planetary Society said: “Skipping to much, much larger sizes, an asteroid the size of the dinosaur – and 70 percent of the species on Earth – killer at 10km in size hits on time scales more like 100 million years.”
A series of iconic purported UFO images, including some that were featured in the “The X-Files” TV show, are up for auction.
The images are part of a Sotheby’s online auction devoted to space photography. They include a lot of six prints by “Billy” Eduard Albert Meier that are from Switzerland in 1975. “These images purport to depict an interstellar visit by spacecraft from the planet Erra, two with a single UFO moving slowly over the town of Berg Rumlikon, and four images depicting a single UFO in a forested hilly area of Schmidrüti,” said Sotheby’s in a statement.
“One of the images in this lot was used to create the famous ‘I Want to Believe’ poster featured in the first three seasons of The X-Files,” the auction house explained.
The poster was often seen in the office of FBI Special Agent Fox Mulder, played by David Duchovny. The lot with the image used to create the ‘I Want to Believe’ poster has a pre-sale estimate of $6,000 to $9,000.
The sale also includes two Meier photos used in the series trailer for the 2016 reboot of the show. One image is part of a set of seven vintage chromogenic prints by Meier in Bachtelhörnli, Switzerland, on March 28, 1976. This lot also has a pre-sale estimate of $6,000 to $9,000.
The image used to create the famous “I Want to Believe” poster featured in the first three seasons of “The X-Files.” (Courtesy Sotheby’s)
Another image used in the trailer reboot is part of four vintage chromogenic prints by Meier in Schmidrüti, Berg Rumlikon, and Winkelreit-Wetzikon Switzerland in 1975. The lot has a pre-sale estimate of $4,000 to $6,000.
Other photos in the auction include images from the estate of Bill Taub, NASA’s first senior photographer, who documented every major space event from Project Mercury to the end of the Apollo missions.
One of the images, part of a group of six vintage chromogenic prints, that was featured in the trailer for the 2016 reboot of “The X-Files.” (Courtesy Sotheby’s)
Photos captured by NASA’s Lunar Orbiters area also up from auction, as well as images from the vintage NASA photo collection of dealer Philip Kulpa.
Another image, part of a group of four vintage chromogenic prints, that was used in the trailer for for the 2016 reboot of “The X-Files.” (Courtesy Sotheby’s)
The auction, which opened Tuesday, runs until Dec. 3.
A new photo of the second interstellar object ever discovered, Comet 2I/Borisov, shows off the mysterious comet and its impressive tail.
The image, taken by astronomers at Yale University, details the scope of the comet’s tail, which is nearly 100,000 miles long — roughly 14 times the size of Earth.
“It’s humbling to realize how small Earth is next to this visitor from another solar system,” Yale astronomer Pieter van Dokkum said in the statement.
Left: A new image of the interstellar comet 2l/Borisov. Right: A composite image of the comet with a photo of the Earth to show scale. (Pieter van Dokkum, Cheng-Han Hsieh, Shany Danieli, Gregory Laughlin)
The new image was taken on Nov. 24 from the Keck Observatory in Hawaii.
The interstellar comet was discovered on Aug. 30 by astronomer Gennady Borisov. Unlike its predecessor, Ouamuamua, it will be observable for an extended period of time.
In September, NASA JPL said 2I/Borisov is approximately 260 million miles from the sun and will reach its closest point, known as perihelion, on Dec. 8, 2019, when it gets within 190 million miles of the sun.
“Astronomers are taking advantage of Borisov’s visit, using telescopes such as Keck to obtain information about the building blocks of planets in systems other than our own,” Yale astronomer Gregory Laughlin added in the statement.
Researchers believe the comet’s nucleus is 1 mile wide and as it started to react to the Sun’s warming effect, it has started to take on a “ghostly” appearance, the researchers added.
A study published in October suggested that Comet 2I/Borisov could be carrying water on it from beyond the Solar System. If the findings are accurate, it would be the first time water from outside the Solar System has been detected.
2I/Borisov is the second interstellar object discovered, following the mysterious cigar-shaped Oumuamua, which was discovered in October 2017. No longer observable by telescopes as of January 2018, many have speculated what the object is. Some have theorized it may have been a light sail sent from an intelligent extraterrestrial civilization, a comet or an asteroid.
Artist’s illustration of ‘Oumuamua, the first known interstellar object spotted in our solar system. (M. Kornmesser/ESO)
The mystery about its exact nature deepened late last year when NASA said it was looking at the object for two months and did not originally see it.
In the past three decades, scientists have found more than 4,000 exoplanets. And the discoveries will keep rolling in; observations suggest that every star in the Milky Way galaxy hosts more than one planet on average.
Given a convergence of ground- and space-based capability, artificial intelligence/machine learning research and other tools, are we on the verge of identifying what is universally possible for life — or perhaps even confirming the existence of extraterrestrial intelligence?ADVERTISING
Is 2020 the celestial payoff year, in which objects of interest are found to offer “technosignatures,” indicators of technology developed by advanced civilizations?
Space.com asked top SETI (search for extraterrestrial intelligence) experts about what next year may signal regarding detecting other starfolk.
“Well, despite being the widely celebrated 100-year anniversary of the election of Warren G. Harding, 2020 will not likely gain fame as the year we first discover extraterrestrial life,” said Seth Shostak, a senior astronomer at the SETI Institute in Mountain View, California.
The search for intelligent beings elsewhere, Shostak said, is largely conducted by checking out nearby star systems for either narrow-band radio signals or brief flashes of laser light. And those might succeed at any time, he told Space.com.
“But one should remember that this type of search is gaining speed in an exponential fashion, and that particular technical fact allows a crude estimate of when SETI might pay off. If we take — for lack of a better estimate — Frank Drake’s opinion that there might be 10,000 broadcasting societies in the Milky Way, then we clearly have to examine at least one [million] – 10 million stellar systems to have a reasonable chance of tripping across one. That goal will be reached in the next two decades, but certainly not in 2020,” Shostak said.
But there are still reasons for intelligent-alien hunters to be excited and optimistic about the coming year. Multiple existing projects will either be expanded or improved in 2020, Shostak said. For example, the SETI Institute will get new receivers for the Allen Telescope Array in northern California, and both the SETI Institute and the University of California, Berkeley, will conduct new searches for possible laser technosignatures.
“And, of course, there’s always the unexpected,” Shostak said. “In 1996, the biggest science story of the year was the claim that fossilized Martian microbes had been found in a meteorite. No one really saw that coming. So one can always hope to be taken by surprise.”
“I am skeptical about picking a specific year for the first discovery. Previous predictions of success have been wrong,” said Michael Michaud, author of the thought-provoking book “Contact with Alien Civilizations: Our Hopes and Fears about Encountering Extraterrestrials” (Copernicus, 2007).
“I and others have observed that the continued improvement of our search technologies and strategies could boost the odds for success,” Michaud said, noting that the primary focus of SETI remains on radio signals. “However, we still don’t cover all frequencies, all skies, all of the time. Other types of searches have failed, too, such as looking for laser signals or Dyson spheres [ET mega-engineering projects]. Those campaigns usually have limited funding and often don’t last long.”
A new possibility has arisen because of exoplanet discoveries, Michaud said: “In some cases, astronomers now can look for chemical evidence of life in planetary atmospheres. It is conceivable that we will find simple forms of life before we find signals from a technological civilization.”
If astronomers do someday confirm a SETI detection, how should they announce the discovery? It is an old question that has been answered in several ways.
“The prevailing opinion among radio astronomers has been that the news will leak quickly. If that is correct, scientific and governmental authorities won’t have much time for developing a public-affairs strategy,” Michaud said.
“It remains possible that the sophisticated monitoring capabilities of intelligence agencies might be the first to detect hard evidence,” Michaud said. “One might think that the government would have a plan to deal with such an event.”
But, Michaud said that his own experience suggests that such plans are unlikely to be drawn up due to a “giggle factor” and would be forgotten as officials rotated out of their positions. He previously represented the U.S. Department of State in interagency discussions of national space policy.Advertisement
“While I’m enthusiastic at the reinvigoration of technological-signatures work, and in particular the growth in looking across much of the electromagnetic spectrum, I think this is going to be a long-term project. I estimate a very small probability of success in any given year,” said Pete Worden, executive director of the Breakthrough Initiatives. “But those chances are now orders of magnitude better than they were even a decade ago.”
Breakthrough Initiatives is tackling the big question of life in the universe, the notable query about whether or not Earthkind is alone. Breakthrough Initiatives is a multifaceted group that’s reinvigorating the search for extraterrestrial intelligence.
“The Breakthrough Initiatives is committed to full and immediate disclosure of any and all results,” Worden said. “We would rely on the principal investigators of our projects, along with their home institutions, to prepare and release both scientific reports and public announcements.”
Preparing for discovery
Despite the ongoing work by Breakthrough Listen, NASA’s Transiting Exoplanet Survey Satellite (TESS) and research into the detection of promising biosignatures and technosignatures, there’s no reason to think 2020 would be the year for discovery, said Steven Dick, a recognized astrobiology scholar and writer of the award-winning book “Astrobiology, Discovery, and Societal Impact” (Cambridge University Press, 2018).
“In my view, all these things combine to increase the chances over the next decade of finding extraterrestrial intelligence. I would caution, though, that any discovery will be an extended process, consisting of detection and interpretation before any understanding is achieved,” Dick said. “This is clear from the history of discovery, even when we thought we had evidence in hand.”
Like Shostak, he cited the Mars meteorite ALH 84001, which in 1996 generated excitement and debate that ancient, microscopic life existed on the Red Planet.
“One thing that is certain is that we are getting a better handle on the issues of societal impact, should such a discovery be made. Many more social sciences and humanities people are getting involved in astrobiology, which is all to the good. In other words, we are preparing for discovery,” Dick said. “So, I see the search advancing incrementally next year, but with an accelerating possibility that life will be discovered in the near future.”
“We are right now on the verge of finding out whether there is life elsewhere in the universe, and there are three ways we could find it. Think of it as a three-way horse race to find ET,” Vakoch said.
But will any of the horses cross the finish line in 2020?
It all depends on the prevalence of life beyond Earth, Vakoch said, and the number of targets we can scan with available technologies — whether these instruments are located in Earth-based observatories, in space-based telescopes or in craft that travel to other planets and moons in our solar system, Vakoch told Space.com.
So, will scientists find intelligent alien life next year?Advertisement
“It all depends on how plentiful intelligent extraterrestrials are. If one in 10,00 star systems is home to an advanced civilization trying to make contact, then we’re behind schedule in making first contact, and the news we’re not alone in the universe could well come in 2020,” Vakoch said.
And there are expectations for microbial life, similar to Earth’s bacteria, to be even more widely spread throughout space than intelligent life.
But bacteria can’t send us radio signals. “We need to develop new technologies to discover them at a distance,” Vakoch said. “As the next generation of space telescopes is launched, we will increase our chances of detecting signs of life through changes to the atmospheres of planets that orbit other stars, giving us millions of targets in our search for even simple life in the cosmos.”
By the end of 2020, we’ll be within a few months of the much-awaited launch of NASA’s James Webb Space Telescope, Vakoch said, which will be able to study the atmospheres of exoplanets for potential signs of life. But it could take much longer, until after the launch of the European Space Agency’s Atmospheric Remote-sensing Infrared Exoplanet Large-survey, or ARIEL, in 2028, before we have “definitive proof” of extraterrestrial microbes through telltale alterations in the atmospheres of exoplanets, Vakoch said.
Living with uncertainty
There are a number of spacecraft in the proposal stage that could conceivably detect extraterrestrial life within our solar system, “but don’t hold your breath for discovery by 2020,” Vakoch said. “But if we do someday find even microbial life elsewhere in our solar system that has an independent origin from terrestrial life, then we would know that the entire universe is chock-full of life.”
Humans cannot control whether or not there is life elsewhere in the universe, of course.
“Either it’s there or it’s not,” Vakoch said. “We may not be able to decide whether we’ll find it in 2020, but we have a tremendous capacity to decide whether we will find it eventually, if it’s out there to be discovered.”
“To be human is to live with uncertainty,” Vakoch concluded. “If we demand guarantees before we begin searching, then we are guaranteed to find nothing. But if we are willing to commit to the search in the coming year and long afterwards, even without knowing we will succeed, then we are sure to discover that there is at least one civilization in the universe that has the passion and the determination to understand its place in the cosmos — and that civilization is us.”
The fastest manmade object isn’t a hypersonic jet or spacecraft, but a large manhole cover…. When the US started doing underground nuclear testing, nobody really knew what would happen. One test bomb was placed at the bottom of a 485-foot deep shaft on July 26, 1957, and someone thought it was a good idea to put a half-ton iron manhole cover on top to contain the explosion. The bomb turned the shaft into the world’s largest Roman candle, and the manhole cover was nowhere to be found. Robert Brownlee, an astrophysicist who designed the test, wanted to repeat the experiment with high-speed cameras so he could figure out what happened to the cover. So another experiment was created, this time 500-feet deep, and a similar half-ton manhole cover was placed on top. On August 27, 1957, they detonated the bomb. The high-speed cameras barely caught a view of the cover as it left the top of the shaft and headed into oblivion. Brownlee used the frames to calculate the speed to be more than 125,000 miles per hour…. more than five times the escape velocity of the Earth, and the fastest man-made object in history.
Physicists have debated the whereabouts of the two manhole covers ever since. Recently, with the help of supercomputers and a lot more scientific knowledge, physicists are certain that they wouldn’t have had time to burn up completely before exiting the atmosphere. This means both of the remaining pieces would have passed Pluto’s orbit sometime around 1961 and are way beyond the edge of the solar system by now. 🙂
Theoreticians in two different fields defied the common knowledge that planets orbit stars like the Sun. They proposed the possibility of thousands of planets around a supermassive black hole.
“With the right conditions, planets could be formed even in harsh environments, such as around a black hole,” says Keiichi Wada, a professor at Kagoshima University researching active galactic nuclei which are luminous objects energized by black holes.
According to the latest theories, planets are formed from fluffy dust aggregates in a protoplanetary disk around a young star. But young stars are not the only objects that possess dust disks. In a novel approach, the researchers focused on heavy disks around supermassive black holes in the nuclei of galaxies.
“Our calculations show that tens of thousands of planets with 10 times the mass of the Earth could be formed around 10 light-years from a black hole,” says Eiichiro Kokubo, a professor at the National Astronomical Observatory of Japan who studies planet formation. “Around black holes there might exist planetary systems of astonishing scale.”
Some supermassive black holes have large amounts of matter around them in the form of a heavy, dense disk. A disk can contain as much as a hundred thousand times the mass of the Sun worth of dust. This is a billion times the dust mass of a protoplanetary disk.
In a low temperature region of a protoplanetary disk, dust grains with ice mantles stick together and evolve into fluffy aggregates. A dust disk around a black hole is so dense that the intense radiation from the central region is blocked and low temperature regions are formed. The researchers applied the planet formation theory to circumnuclear disks and found that planets could be formed in several hundred million years.
Currently there are no techniques to detect these planets around black holes. However, the researchers expect this study to open a new field of astronomy.
India has finally made it official: the country’s long-silent Chandrayaan-2 moon lander Vikram did, in fact, crash into the lunar surface in September, apparently because of an issue with its braking rockets.
“The first phase of descent was performed nominally from an altitude of 30 km to 7.4 km (18 miles to 4.5 miles) above the moon surface,” Singh wrote, describing the lander’s descent, in which the craft slowed from 5,521 feet per second (1,683 meters per second) to 479 feet per second (146 m per second).
“During the second phase of descent, the reduction in velocity was more than the designed value,” he continued. “Due to this deviation, the initial conditions at the start of the fine braking phase were beyond the designed parameters. As a result, Vikram hard landed within 500 m of the designated landing site,” Singh said.
This is the first time that the Indian government has formally acknowledged the crash landing.
On Sept. 10, following the loss of communication from what we now know was a crash on the moon, the ISRO announced that the “Vikram lander has been located by the orbiter of Chandrayaan–2, but no communication with it yet. All possible efforts are being made to establish communication with lander.”
One explanation for why it has taken so long for the Indian government to formally recognize the crash is that, according to the ISRO, they were still trying to figure out exactly what happened. Engineers were working to reconstruct the events that led to the loss of communication with the lander and the ISRO was waiting until that work was done to make a formal announcement, S. Somanath, who directs the ISRO’s Vikram Sarabhai Space Centre, said at the International Astronautical Congress (IAC) on Oct. 21, according to a statement.
However, while Somanath held off on making any formal declarations about Vikram, he did recognize that the craft most likely hit the moon so fast that it was “beyond its survivability,” he said in the statement.
There’s a “dark impactor” blasting holes in our galaxy. We can’t see it. It might not be made of normal matter. Our telescopes haven’t directly detected it. But it sure seems like it’s out there.
“It’s a dense bullet of something,” said Ana Bonaca, a researcher at the Harvard-Smithsonian Center for Astrophysics, who discovered evidence for the impactor.
Bonaca’s evidence for the dark impactor, which she presented April 15 at the conference of the American Physical Society in Denver, is a series of holes in our galaxy’s longest stellar stream, GD-1. Stellar streams are lines of stars moving together across galaxies, often originating in smaller blobs of stars that collided with the galaxy in question. The stars in GD-1, remnants of a “globular cluster” that plunged into the Milky Way a long time ago, are stretched out in a long line across our sky.
Under normal conditions, the stream should be more or less a single line, stretched out by our galaxy’s gravity, she said in her presentation. Astronomers would expect a single gap in the stream, at the point where the original globular cluster was before its stars drifted away in two directions. But Bonaca showed that GD-1 has a second gap. And that gap has a ragged edge — a region Bonaca called GD-1’s “spur” — as if something huge plunged through the stream not long ago, dragging stars in its wake with its enormous gravity. GD-1, it seems, was hit with that unseen bullet. [Gallery: Dark Matter Throughout the Universe]RECOMMENDED VIDEOS FOR YOU…CLOSEVolume 0% PLAY SOUND
“We can’t map [the impactor] to any luminous object that we have observed,” Bonaca told Live Science. “It’s much more massive than a star… Something like a million times the mass of the sun. So there are just no stars of that mass. We can rule that out. And if it were a black hole, it would be a supermassive black hole of the kind we find at the center of our own galaxy.”
It’s not impossible that there’s a second supermassive black hole in our galaxy, Bonaca said. But we’d expect to see some sign of it, like flares or radiation from its accretion disk. And most large galaxies seem to have just a single supermassive black hole at their center.
With no giant, bright objects visible zipping away from GD-1, and no evidence for a hidden, second supermassive black hole in our galaxy, the only obvious option left is a big clump of dark matter. That doesn’t mean the object is definitely, 100%, absolutely made of dark matter, Bonaca said.
“It could be that it’s a luminous object that went away somewhere, and it’s hiding somewhere in the galaxy,” she added.
But that seems unlikely, in part due to the sheer scale of the object.
“We know that it’s 10 to 20 parsecs [30 to 65 light-years] across,” she said. “About the size of a globular cluster.”
But it’s hard to entirely rule out a luminous object, in part because the researchers don’t know how fast it was moving during the impact. (It may have been moving very fast, but not quite as heavy as expected — a true dark bullet — Bonaca said. Or it could have been moving more slowly but been very massive — a sort of dark hammer.) Without an answer to that question, it’s impossible to be certain where the thing would have ended up.
Still, the possibility of having found a real dark matter object is tantalizing.
Right now, researchers don’t know what dark matter is. Our universe seems to act like the luminous matter, the stuff we can see is just a small fraction of what’s out there. Galaxies bind together as if there’s something heavy inside them, clustered in their centers and creating enormous gravity. So most physicists reason that there’s something else out there, something invisible. There are lots of different opinions as to what it’s made of, but none of the efforts to directly detect dark matter on Earth have yet worked.
If dark matter is “clumpy,” then it’s concentrated in irregular chunks distributed roughly across galaxies — much like the luminous matter we see concentrated in stars and nebulae. Some alternative theories, including theories that suggest dark matter doesn’t exist at all, wouldn’t include any clumps — and would have the effects of dark matter distributed smoothly across galaxies.Advertisement
So far, Bonaca’s discovery is one of a kind, so new that it hasn’t yet been published in a peer-reviewed journal (though it was met appreciatively by the crowd of physicists at the prestigious conference).
To pull it off, she relied on data from the Gaia mission, an European Space Agency program to map billions of stars in our galaxy and their movements across the sky. It formed the best existing catalog of the stars that seem to be part of GD-1.
Bonaca buttressed that data with observations from the Multi Mirror Telescope in Arizona, which showed which stars were moving toward Earth, and which were moving away. That helped distinguish between stars that were really moving with GD-1, and those that just sat next to it in Earth’s sky. That effort produced the most precise image ever of GD-1, which revealed the second gap, the spur, and a previously unseen region of the stellar stream.
Down the road, Bonaca said, she wants to do more mapping projects to reveal other regions of the sky where something unseen seems to be knocking stars around. The goal, she said, is to eventually map clumps of dark matter all across the Milky Way.
For the first time in the history of space exploration, scientists have measured the seasonal changes in the gases that fill the air directly above the surface of Gale Crater on Mars.Share: FULL STORY
For the first time in the history of space exploration, scientists have measured the seasonal changes in the gases that fill the air directly above the surface of Gale Crater on Mars. As a result, they noticed something baffling: oxygen, the gas many Earth creatures use to breathe, behaves in a way that so far scientists cannot explain through any known chemical processes.
Over the course of three Mars years (or nearly six Earth years) an instrument in the Sample Analysis at Mars (SAM) portable chemistry lab inside the belly of NASA’s Curiosity rover inhaled the air of Gale Crater and analyzed its composition. The results SAM spit out confirmed the makeup of the Martian atmosphere at the surface: 95% by volume of carbon dioxide (CO2), 2.6% molecular nitrogen (N2), 1.9% argon (Ar), 0.16% molecular oxygen (O2), and 0.06% carbon monoxide (CO). They also revealed how the molecules in the Martian air mix and circulate with the changes in air pressure throughout the year. These changes are caused when CO2 gas freezes over the poles in the winter, thereby lowering the air pressure across the planet following redistribution of air to maintain pressure equilibrium. When CO2 evaporates in the spring and summer and mixes across Mars, it raises the air pressure.
Within this environment, scientists found that nitrogen and argon follow a predictable seasonal pattern, waxing and waning in concentration in Gale Crater throughout the year relative to how much CO2 is in the air. They expected oxygen to do the same. But it didn’t. Instead, the amount of the gas in the air rose throughout spring and summer by as much as 30%, and then dropped back to levels predicted by known chemistry in fall. This pattern repeated each spring, though the amount of oxygen added to the atmosphere varied, implying that something was producing it and then taking it away.
“The first time we saw that, it was just mind boggling,” said Sushil Atreya, professor of climate and space sciences at the University of Michigan in Ann Arbor. Atreya is a co-author of a paper on this topic published on November 12 in the Journal of Geophysical Research: Planets.
As soon as scientists discovered the oxygen enigma, Mars experts set to work trying to explain it. They first double- and triple-checked the accuracy of the SAM instrument they used to measure the gases: the Quadrupole Mass Spectrometer. The instrument was fine. They considered the possibility that CO2 or water (H2O) molecules could have released oxygen when they broke apart in the atmosphere, leading to the short-lived rise. But it would take five times more water above Mars to produce the extra oxygen, and CO2 breaks up too slowly to generate it over such a short time. What about the oxygen decrease? Could solar radiation have broken up oxygen molecules into two atoms that blew away into space? No, scientists concluded, since it would take at least 10 years for the oxygen to disappear through this process.
“We’re struggling to explain this,” said Melissa Trainer, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland who led this research. “The fact that the oxygen behavior isn’t perfectly repeatable every season makes us think that it’s not an issue that has to do with atmospheric dynamics. It has to be some chemical source and sink that we can’t yet account for.”
To scientists who study Mars, the oxygen story is curiously similar to that of methane. Methane is constantly in the air inside Gale Crater in such small quantities (0.00000004% on average) that it’s barely discernable even by the most sensitive instruments on Mars. Still, it’s been measured by SAM’s Tunable Laser Spectrometer. The instrument revealed that while methane rises and falls seasonally, it increases in abundance by about 60% in summer months for inexplicable reasons. (In fact, methane also spikes randomly and dramatically. Scientists are trying to figure out why.)
With the new oxygen findings in hand, Trainer’s team is wondering if chemistry similar to what’s driving methane’s natural seasonal variations may also drive oxygen’s. At least occasionally, the two gases appear to fluctuate in tandem.
“We’re beginning to see this tantalizing correlation between methane and oxygen for a good part of the Mars year,” Atreya said. “I think there’s something to it. I just don’t have the answers yet. Nobody does.”
Oxygen and methane can be produced both biologically (from microbes, for instance) and abiotically (from chemistry related to water and rocks). Scientists are considering all options, although they don’t have any convincing evidence of biological activity on Mars. Curiosity doesn’t have instruments that can definitively say whether the source of the methane or oxygen on Mars is biological or geological. Scientists expect that non-biological explanations are more likely and are working diligently to fully understand them.
Trainer’s team considered Martian soil as a source of the extra springtime oxygen. After all, it’s known to be rich in the element, in the form of compounds such as hydrogen peroxide and perchlorates. One experiment on the Viking landers showed decades ago that heat and humidity could release oxygen from Martian soil. But that experiment took place in conditions quite different from the Martian spring environment, and it doesn’t explain the oxygen drop, among other problems. Other possible explanations also don’t quite add up for now. For example, high-energy radiation of the soil could produce extra O2 in the air, but it would take a million years to accumulate enough oxygen in the soil to account for the boost measured in only one spring, the researchers report in their paper.
“We have not been able to come up with one process yet that produces the amount of oxygen we need, but we think it has to be something in the surface soil that changes seasonally because there aren’t enough available oxygen atoms in the atmosphere to create the behavior we see,” said Timothy McConnochie, assistant research scientist at the University of Maryland in College Park and another co-author of the paper.
The only previous spacecraft with instruments capable of measuring the composition of the Martian air near the ground were NASA’s twin Viking landers, which arrived on the planet in 1976. The Viking experiments covered only a few Martian days, though, so they couldn’t reveal seasonal patterns of the different gases. The new SAM measurements are the first to do so. The SAM team will continue to measure atmospheric gases so scientists can gather more detailed data throughout each season. In the meantime, Trainer and her team hope that other Mars experts will work to solve the oxygen mystery.
“This is the first time where we’re seeing this interesting behavior over multiple years. We don’t totally understand it,” Trainer said. “For me, this is an open call to all the smart people out there who are interested in this: See what you can come up with.”
Scientists have discovered ancient asteroid ice fossils that could reveal what our solar system was like billions of years ago.
In a new study, the scientists analyzed a 4.6-billion-year-old primitive meteorite, called Acfer 094, that crash-landed in the Sahara desert in Algeria in 1990. (A primitive meteorite is a rocky remnant of the solar nebula, or the gaseous cloud that some say condensed into the objects in the solar system, that has fallen to Earth).
In the meteorite, the scientists found what seem to be ice fossils, and the discovery is helping to illuminate how asteroids formed in the early solar system and what the materials that eventually formed our neighboring planets may have looked like billions of years ago.
The researchers discovered what they think are the remnants of fluffy ice dust, or porous silicate, sulfide and organic material that make up “one of the building blocks of planets in the solar system formation model,” Meguma Matsumoto, lead author of the study, told Space.com in an email. These fluffy ice-dust remnants, also known as ultra-porous lithology, look like tiny “fluffy aggregates of silicate grains covered with an H2O icy mantle,” Matsumoto said.
The pores in this material were likely created when ice that previously filled the space disappeared, the team found. So, by finding the pores, they discovered evidence of this ancient ice.
In the early solar system, swirling dust, gas and sometimes ice compacted and formed objects like rocky asteroids or even larger protoplanets (astronomical objects about the same size of the moon that are formed when planetesimals, or small solid astronomical objects, combine). And some of these small, newly formed protoplanets contained ice. As they grew, they heated up, and that early-solar-system material they started with started to melt and recrystallize, the study authors explained.
These findings allow researchers to look back in time at the material that eventually formed objects like asteroids and the planets in our solar system, and the study vastly improves scientists’ understanding of how those materials came to form those objects.
Researchers have previously identified interactions between water and rocks that happened when ice melted in the larger objects that broke off into objects like Acfer 094. However, until now, it has remained a mystery how this ice got there, Matsumoto said.
The discovery of the asteroid ice fossils reveals how primordial ice was “brought into and distributed to the meteorite parent body,” Matsumoto said.
Using a model that simulated how Acfer 094 grew and how the planets in the solar system formed, the researchers determined that fluffy ice and dust particles came together in bigger bodies beyond the snow line — the distance from the sun where it’s cold enough for solid ice grains to form — and then migrated toward the sun, Epifanio Vaccaro, curator of petrology at the Natural History Museum in London and co-author of the study, said in a statement. As these bodies moved inward, toward the sun, this ice started to melt, leaving the ice fossils in its place, he said.
CAPE CANAVERAL, Fla. — A shooting star has landed here at NASA’s Kennedy Space Center (KSC).
Ahead of the first planned launch of its Dream Chaser spacecraft (scheduled for sometime in fall 2021) Sierra Nevada Corp. — the company behind the small, space shuttle-like vessel — recently delivered a test article of its cargo module, dubbed Shooting Star, to KSC.
The Shooting Star is a 15-foot (4.6 meters) module that will attach to the aft (or back) portion of the Dream Chaser and provide room for an additional 10,000 lbs. (4,500 kilograms) of cargo — both pressurized and unpressurized.
On Tuesday (Nov. 19) Steven Lindsey, a former astronaut and vice president of space exploration systems for Sierra Nevada, was here at Kennedy Space Center to unveil the new cargo module.
“The cargo module is really interesting because it’s sort of the unsung hero of the whole Dream Chaser cargo system design,” Lindsey said.
He noted that the module has a unique shape. “It angles in as it goes up,” he said.
This is because the vehicle has to fit inside the launch vehicle’s payload fairing and carry unpressurized cargo, Lindsey said. He pointed to a series of gray boxes that were attached to the test article’s exterior. According to Lindsey, the boxes represented external payloads, or payloads that can travel to the International Space Station (ISS) while attached to the module’s exterior.
Each Shooting Star cargo module can support three payloads weighing up to 1,100 lbs. (500 kg) each or one payload weighing as much as 3,300 lbs. (1,500 kg). Once the module is at the station, the Canadarm2 robotic arm would unload the payload and install it on the station’s exterior.
Each of those ports has power and data connections to support a variety of payloads, including small satellites that deploy in orbit. “You name it, we can carry it,” Lindsey said.
During the event, Lindsey also announced that NASA has officially approved the first cargo mission to the ISS, which is scheduled for 2021. Lindsey said ground operations crews will use the Shooting Star test article to test loading and unloading procedures, ensuring that the design meets NASA requirements.
He reiterated what NASA recently announced: that the spacecraft will also be used to reach and resupply the Lunar Gateway, a moon-orbiting space station that NASA plans to use as a staging point for its lunar surface missions.
Sierra Nevada was named as one of the newly approved vendors that can bid on NASA’s Commercial Lunar Payload Services contracts. For that to happen, the Dream Chaser will have to have its satellite bus attached, which means Dream Chaser will be able to participate in NASA’s Artemis program.
The versatile vehicle can also serve as both a free-flying space station (with an inflatable module attached) and a means of servicing satellites in orbit. During the event, Lindsey revealed that Dream Chaser has the potential to boost satellites to a higher orbit, pull them out of orbit and potentially make repairs (with the addition of robotic arms).
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“This vehicle is perfectly suited for a variety of missions,” Lindsey told Space.com. “Dream Chaser can dock, or it can berth; it’s NASA’s choice. So that means it has applications in both cislunar space as well as low Earth orbit, and even higher orbits.”
Although the spacecraft was originally designed to carry humans, its first delivery will be a cargo resupply mission to the space station. Sierra Nevada lost out to SpaceX and Boeing when the company tried to bid on a contract from NASA to launch astronauts in 2014. However, in 2016, NASA selected Dream Chaser for its Commercial Resupply Services 2 contract, awarding Sierra Nevada a launch contract for six cargo missions to the space station by 2024.
The vehicle will launch and land from KSC, taking off on a United Launch Alliance Vulcan Centaur rocket. Company representatives said that if the still-in-development Vulcan wasn’t quite ready to fly when Dream Chaser is, Sierra Nevada can send its space plane to the ISS atop an Atlas V rocket.
Dream Chaser will land at the shuttle landing facility here at KSC — the same runway where its predecessor, the space shuttle, touched down. However, the plane can land on any runway in the world that can support a Boeing 737 airplane.
Because of its unique capabilities, the space plane will be a huge boost to scientific research, as experiments conducted on the orbiting outpost will return to the hands of ground-based researchers much sooner than is currently possible.
When experiments are carried to the ISS — which operates in low Earth orbit, a region from 99 to 1,200 miles (160 to 2,000 kilometers) above the planet’s surface — they must remain there until the next cargo ship arrives, which could be several months later. According to Lindsey, Dream Chaser can shorten that time frame significantly.Advertisement
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Sierra Nevada spokesperson Kimberly Schwandt said that once Dream Chaser has left the space station, any delicate experiments on board could be back on Earth in under 2 hours.
“As we like to say, wings are back,” Schwandt said during Tuesday’s event.
The Dream Chaser spacecraft is currently under construction and is scheduled to launch its first mission on behalf of NASA.
Gamma-ray bursts, the most powerful kinds of explosions known in the universe, can generate even more energetic light beams than astronomers previously realized, according to a set of new studies.
The new research suggests that scientists may have been missing about half of the energy that gamma-ray bursts produce, and offers one possible explanation for how that light reaches such high energy levels. These findings shed light on how these extraordinary explosions happen, and how they can reshape the universe, researchers said.
A gamma-ray burst gives off as much energy in milliseconds to minutes as the sun is expected to emit during its entire 10-billion-year lifetime. Previous research suggested that the deaths of giant stars or the merging of neutron stars or black holes trigger these explosions.
Previous research suggested that gamma-ray bursts might generate extraordinarily strong gamma-rays. But scientists have not been able to spot such energetic light — photons with energies higher than 100 billion electron volts.
For comparison, that is about “100 billion times more energetic than the optical light our eyes are sensitive to, or around 100 million times more energetic than X-ray photons, those used when we get an X-ray of our bones,” Edna Ruiz Velasco, an astrophysicist at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany, told Space.com. She is a co-author of one ofthreestudies on gamma-ray bursts in the Nov. 21 issue of the journal Nature.
Now, for the first time, researchers have detected such ultra-high-energy light from gamma-ray bursts. The scientists analyzed two gamma-ray bursts detected by NASA’s Fermi Gamma-ray Space Telescope and NASA’s Swift Observatory. One burst, known as GRB 180720B, was seen in July 2018 about 7 billion light-years from Earth; the other, GRB 190114C, was spotted in January 2019 about 4.5 billion light-years away.
In the aftermath of each detection, other instruments turned to observe the bursts, and in both cases, they saw incredibly energetic gamma-rays. After GRB 180720B, the High Energy Stereoscopic System array of telescopes in Namibia detected gamma-rays with energies between 100 billion and 440 billion electron volts. After GRB 190114C, two telescopes in La Palma, Spain, run by the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) collaboration, detected gamma-rays with energies ranging from 200 billion to 1 trillion electron volts.
After realizing how energetic that 2019 burst was, the researchers recruited more than two dozen observatories on the ground and in space to join MAGIC is observing the event. The scientists used that data to analyze the energies and wavelengths of the radiation in detail to learn more about its origins.
The researchers who made these detections believe that the observations suggest that until now, scientists may have failed to see a whopping half of the energy that gamma-ray bursts can emit. “Our measurements show that the energy released in very-high-energy gamma-rays is comparable to the amount radiated at all lower energies taken together,” study co-author Konstancja Satalecka, an astrophysicist at the German Electron Synchrotron in Hamburg, said in a statement from that facility. “That is remarkable!”
Prior work has suggested that most gamma-rays in these bursts are emitted by electrons spiraling through powerful magnetic fields at nearly the speed of light. But the authors of the new research believe a different mechanism is powering the ultra-high-energy gamma-rays produced in the two recent events.
Based on their analysis of this light, the scientists suggested that the most energetic light from gamma-ray bursts likely results from photons crashing into the highest-energy electrons from the outbursts. In essence, the photons and electrons “shake hands and exchange their energies — the photons get the very high energy, and the electrons lose the energy,” Razmik Mirzoyan, an astrophysicist at the Max Planck Institute for Physics in Munich, co-author of two of the new papers and a spokesperson for MAGIC, told Space.com.
The scientists expect that future research will continue to detect ultra-high-energy gamma-rays from gamma-ray bursts, now that astronomers know what to look for. Such data will help the scientists better understand the “physics of gamma-ray bursts and their interactions with their surroundings,” Mirzoyan said.
There’s a hole in the story of how our universe came to be. First, the universe inflated rapidly, like a balloon. Then, everything went boom.
But how those two periods are connected has eluded physicists. Now, a new study suggests a way to link the two epochs.
In the first period, the universe grew from an almost infinitely small point to nearly an octillion (that’s a 1 followed by 27 zeros) times that in size in less than a trillionth of a second. This inflation period was followed by a more gradual, but violent, period of expansion we know as the Big Bang. During the Big Bang, an incredibly hot fireball of fundamental particles — such as protons, neutrons and electrons — expanded and cooled to form the atoms, stars and galaxies we see today.
The Big Bang theory, which describes cosmic inflation, remains the most widely supported explanation of how our universe began, yet scientists are still perplexed by how these wholly different periods of expansion are connected. To solve this cosmic conundrum, a team of researchers at Kenyon College, the Massachusetts Institute of Technology (MIT) and the Netherlands’ Leiden University simulated the critical transition between cosmic inflation and the Big Bang — a period they call “reheating.”
“The post-inflation reheating period sets up the conditions for the Big Bang and, in some sense, puts the ‘bang’ in the Big Bang,” David Kaiser, a professor of physics at MIT, said in a statement. “It’s this bridge period where all hell breaks loose and matter behaves in anything but a simple way.”
When the universe expanded in a flash of a second during cosmic inflation, all the existing matter was spread out, leaving the universe a cold and empty place, devoid of the hot soup of particles needed to ignite the Big Bang. During the reheating period, the energy propelling inflation is believed to decay into particles, said Rachel Nguyen, a doctoral student in physics at the University of Illinois and lead author of the study.Click here for more Space.com videos…CLOSEVolume 0% PLAY SOUND
“Once those particles are produced, they bounce around and knock into each other, transferring momentum and energy,” Nguyen told Live Science. “And that’s what thermalizes and reheats the universe to set the initial conditions for the Big Bang.”
In their model, Nguyen and her colleagues simulated the behavior of exotic forms of matter called inflatons. Scientists think these hypothetical particles, similar in nature to the Higgs boson, created the energy field that drove cosmic inflation. Their model showed that, under the right conditions, the energy of the inflatons could be redistributed efficiently to create the diversity of particles needed to reheat the universe. They published their results Oct. 24 in the journal Physical Review Letters.
A crucible for high-energy physics
“When we’re studying the early universe, what we’re really doing is a particle experiment at very, very high temperatures,” said Tom Giblin, an associate professor of physics at Kenyon College in Ohio and co-author of the study. “The transition from the cold inflationary period to the hot period is one that should hold some key evidence as to what particles really exist at these extremely high energies.”
One fundamental question that plagues physicists is how gravity behaves at the extreme energies present during inflation. In Albert Einstein’s theory of general relativity, all matter is believed to be affected by gravity in the same way, where the strength of gravity is constant regardless of a particle’s energy. However, because of the strange world of quantum mechanics, scientists think that, at very high energies, matter responds to gravity differently.
The team incorporated this assumption in their model by tweaking how strongly the particles interacted with gravity. They discovered that the more they increased the strength of gravity, the more efficiently the inflatons transferred energy to produce the zoo of hot matter particles found during the Big Bang.
Now, they need to find evidence to buttress their model somewhere in the universe.
“The universe holds so many secrets encoded in very complicated ways,” Giblin told Live Science. “It’s our job to learn about the nature of reality by coming up with a decoding device — a way to extract information from the universe. We use simulations to make predictions about what the universe should look like so that we can actually start decoding it. This reheating period should leave an imprint somewhere in the universe. We just need to find it.”
But finding that imprint could be tricky. Our earliest glimpse of the universe is a bubble of radiation left over from a few hundred thousand years after the Big Bang, called the cosmic microwave background (CMB). Yet the CMB only hints at the state of the universe during those first critical seconds of birth. Physicists like Giblin hope future observations of gravitational waves will provide the final clues.
The Jupiter moon Europa’s elusive and enigmatic water-vapor plumes do indeed seem to be real.
NASA’s Hubble Space Telescope has spotted indirect evidence of such plumes emanating from Europa, which is thought to harbor a huge, salty ocean beneath its ice shell. And researchers have now detected one such plume’s water vapor directly for the first time, a new study reports.
“Essential chemical elements (carbon, hydrogen, oxygen, nitrogen, phosphorus and sulfur) and sources of energy, two of three requirements for life, are found all over the solar system. But the third — liquid water — is somewhat hard to find beyond Earth,” study lead author Lucas Paganini, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and American University in Washington, D.C., said in a statement.
“While scientists have not yet detected liquid water directly, we’ve found the next best thing: water in vapor form,” Paganini added.
Paganini and his colleagues used the W.M. Keck Observatory in Hawaii to study the 1,900-mile-wide (3,100 kilometers) Europa, which astrobiologists regard as one of the solar system’s best bets to host alien life.
The researchers observed Europa for 17 nights, from February 2016 through May 2017. On one of those nights — April 26, 2016 — they got a strong signal of water vapor, in the form of a characteristic wavelength of emitted infrared light.
And there was quite a bit of the stuff — about 2,300 tons (2,095 metric tons), according to the researchers’ calculations. That’s almost enough to fill an Olympic-size swimming pool (which contains about 2,750 tons, or 2,500 metric tons, of water).
The researchers think the source of this water is a plume, which could be coming from the buried ocean or from a reservoir of melted ice within Europa’s shell. For starters, the observed volume is much higher than what is predicted to result from “exogenic” processes, such as the stripping of water molecules from Europa’s surface by Jupiter’s powerful radiation belts. And such stripping would likely occur fairly regularly, or at least often enough to be noted more than one night out of 17, Paganini and his team wrote in the new paper, which was published online today (Nov. 18) in the journal Nature Astronomy.Click here for more Space.com videos…Jupiter’s Moon Europa Has Table Salt on SurfaceVolume 0% PLAY SOUND
Multiple lines of evidence now point to the existence of plumes on Europa. For example, in addition to the new results and Hubble’s detection of atomic hydrogen and oxygen (which presumably came from water molecules split apart by radiation), NASA’s Galileo Jupiter probe measured a big increase in the density of plasma, or ionized gas, during a Europa flyby in 1997.
And it’s becoming increasingly clear that Europa’s plumes are sporadic. In that regard, they’re very different from the constant plume wafting from the south pole of Saturn’s icy, ocean-harboring moon Enceladus, which is generated by more than 100 powerful geysers that are always on.
“For me, the interesting thing about this work is not only the first direct detection of water above Europa, but also the lack thereof within the limits of our detection method,” Paganini said.
Plumes like those emanating from Enceladus and Europa are very exciting to astrobiologists, because they’re sending “free samples” from potentially habitable environments out into space for potential snagging by robotic probes. And there’s a possibility that a NASA spacecraft could soon do just that, if everything works out just right.
NASA is developing a mission called Europa Clipper, which is scheduled to launch in the mid-2020s. Clipper will orbit Jupiter but study Europa up close on dozens of flybys, characterizing the moon and its ocean and hunting for spots where a potential life-hunting lander could touch down in the future. Clipper could end up zooming through the plume on one or more of those flybys, if mission team members learn enough about the feature in the coming years — or if they just get really lucky.
Raw video: EarthCam.com live stream captures a bright meteor streak across the St. Louis skyline.
A bright blue flash that streaked through the sky over St. Louis Monday evening was an approximately 220-pound chunk of rock that broke off an asteroid belt between Mars and Jupiter before it entered Earth’s atmosphere, Bill Cooke, of the NASA Meteoroid Environments Office in Alabama, said Tuesday, according to a report.
The fireball was traveling at about 33,500 mph and caused a sonic boom, NASA scientists said, according to The St. Louis Post-Dispatch.
Astronomers have spotted an ultrafast star, traveling at a blistering 6 million km/h, that was ejected by the supermassive black hole at the heart at the Milky Way five million years ago. The discovery of the star, known as S5-HVS1, was made as part of the Southern Stellar Stream Spectroscopic Survey (S5). Located in the constellation of Grus – the Crane – S5-HVS1 was found to be moving ten times faster than most stars in the Milky Way.
Astronomers have spotted an ultrafast star, traveling at a blistering 6 million km/h, that was ejected by the supermassive black hole at the heart at the Milky Way five million years ago.
The discovery of the star, known as S5-HVS1, was made by Carnegie Mellon University Assistant Professor of Physics Sergey Koposov as part of the Southern Stellar Stream Spectroscopic Survey (S5). Located in the constellation of Grus — the Crane — S5-HVS1 was found to be moving ten times faster than most stars in the Milky Way.
“The velocity of the discovered star is so high that it will inevitably leave the galaxy and never return,” said Douglas Boubert from the University of Oxford, a co-author on the study.
Astronomers have wondered about high velocity stars since their discovery only two decades ago. S5-HVS1 is unprecedented due to its high speed and close passage to the Earth, “only” 29 thousand light years away. With this information, astronomers could track its journey back into the center of the Milky Way, where a four million solar mass black hole, known as Sagittarius A*, lurks.
“This is super exciting, as we have long suspected that black holes can eject stars with very high velocities. However, we never had an unambiguous association of such a fast star with the galactic center,” said Koposov, the lead author of this work and member of Carnegie Mellon’s McWilliams Center for Cosmology. “We think the black hole ejected the star with a speed of thousands of kilometers per second about five million years ago. This ejection happened at the time when humanity’s ancestors were just learning to walk on two feet.”
Superfast stars can be ejected by black holes via the Hills Mechanism, proposed by astronomer Jack Hills thirty years ago. Originally, S5-HSV1 lived with a companion in a binary system, but they strayed too close to Sagittarius A*. In the gravitational tussle, the companion star was captured by the black hole, while S5-HVS1 was thrown out at extremely high speed.
“This is the first clear demonstration of the Hills Mechanism in action,” said Ting Li from Carnegie Observatories and Princeton University, and leader of the S5 Collaboration. “Seeing this star is really amazing as we know it must have formed in the galactic center, a place very different to our local environment. It is a visitor from a strange land.”
The discovery of S5-HVS1 was made with the 3.9-meter Anglo-Australian Telescope (AAT) near Coonabarabran, NSW, Australia, coupled with superb observations from the European Space Agency’s Gaia satellite, that allowed the astronomers to reveal the full speed of the star and its journey from the center of the Milky Way.
“The observations would not be possible without the unique capabilities of the 2dF instrument on the AAT,” said Daniel Zucker, an astronomer at Macquarie University in Sydney, Australia, and a member of the S5 executive committee. “It’s been conducting cutting-edge research for over two decades and still is the best facility in the world for our project.”
These results were published on November 4 online in the Monthly Notices of the Royal Astronomical Society, and the S5 collaboration unites astronomers from the United States, United Kingdom, Australia and Chile.
“I am so excited this fast-moving star was discovered by S5,” says Kyler Kuehn, at Lowell Observatory and a member of the S5 executive committee. “While the main science goal of S5 is to probe the stellar streams — disrupting dwarf galaxies and globular clusters — we dedicated spare resources of the instrument to searching for interesting targets in the Milky Way, and voila, we found something amazing for ‘free.’ With our future observations, hopefully we will find even more!”