7 billion-year-old stardust is oldest material found on Earth

Dust-rich outflows of evolved stars similar to the pictured Egg Nebula are plausible sources of the large presolar grains found in meteorites like Murchison.Dust-rich outflows of evolved stars similar to the pictured Egg Nebula are plausible sources of the large presolar grains found in meteorites like Murchison.(Image: © NASA, W. Sparks (STScI) and R. Sahai (JPL). Inset: SiC grain with ~8 micrometers in its longest dimension. Inset image courtesy of Janaína N. Ávila)

Scientists recently identified the oldest material on Earth: stardust that’s 7 billion years old, tucked away in a massive, rocky meteorite that struck our planet half a century ago. 

This ancient interstellar dust, made of presolar grains (dust grains that predate our sun), was belched into the universe by dying stars during the final stages of their lives. Some of that dust eventually hitched a ride to Earth on an asteroid that produced the Murchison meteorite, a massive, 220-lb. (100 kilograms) rock that fell on Sept. 28, 1969, near Murchison, Victoria, in Australia.  ADVERTISING

New analysis of dozens of presolar grains from the Murchison meteorite revealed a range of ages, from about 4 million years older than our sun — which formed 4.6 billion years ago — up to 3 billion years older than our sun, researchers reported in a new study.

Though the universe abounds with floating stardust, no presolar grains have ever been found in Earth’s rocks. That’s because plate tectonics, volcanism and other planetary processes heated and transformed all the presolar dust that may have collected during Earth’s formation, said lead study author Philipp Heck, the Robert A. Pritzker Associate Curator of Meteoritics and Polar Studies at the Field Museum of Natural History in Chicago. 

When large, orphan space rocks form — such as the asteroid that produced Murchison — they, too, can pick up ancient, interstellar dust. But unlike dynamic planets, Murchison’s parent asteroid is “an almost-inert piece of rock that formed from the solar nebula and hasn’t changed since then,” so the presolar grains haven’t been cooked down into another type of mineral, Heck told Live Science.

Most presolar grains measure about 1 micron in length, or are even smaller. But the grains the scientists analyzed for the study were much bigger, ranging from 2 to 30 microns in length. 

“We call them ‘boulders,'” Heck said. “We can see them with an optical microscope.”

Stellar “baby boom”

For the study, Heck and his colleagues examined 40 of these so-called boulders from Murchison, grinding up bits of the meteorite and adding acid, which dissolved minerals and silicates and revealed the acid-resistant presolar grains. 

“I always compare it to burning down the haystack to find the needle,” Heck said.

The researchers used a dating technique that measured the grains’ exposure to cosmic rays during their interstellar journey over billions of years. In space, high-energy particles emanate from different sources, bombarding and penetrating solid objects that pass by. Those cosmic rays react with rock to form new elements that accumulate over time. By measuring the quantity of different elements in presolar grains, scientists can estimate how long the dust has been bathing in cosmic rays. 

Think of it this way: Imagine putting a bucket outside during a rainstorm. As long as the rain falls at a steady rate, you could calculate how long the bucket had been outside based on the amount of rain that it collects, Heck explained.

Most of the grains — about 60% — dated to around 4.6 billion to 4.9 billion years ago. One possible explanation for why there were so many grains of this age is that they were all the product of a “little baby boom” of star birth in our galaxy that took place around 7 billion years ago. 

“And then it took about two to two-and-a-half billion years for those stars to become dust producing,” Heck explained. “When a star forms, it doesn’t produce dust. During most of its life, the star doesn’t produce dust. The stars only produce dust at the end of their lives.”

This discovery supports findings by other astronomers that indicate a dramatic spike in star formation around 7 billion years ago, the researchers reported.

What’s more, many of the grains weren’t traveling through space alone; they journeyed as clumps, “almost like granola clusters,” according to Heck. Though it’s uncertain what bound these grains, other studies have shown that some presolar grains are coated with a sticky film of organic matter, which could have cemented these clusters together, Heck said.

Smells like science

Grinding and analyzing bits of space rock also presented the researchers with an unusual by-product — a strong and very pungent smell. The paste of ground-up meteorite released a stench “like rotten peanut butter,” study co-author Jennika Greer, a graduate student at the Field Museum and the University of Chicago, said in a statement.

“I’ve never smelled rotten peanut butter,” Heck told Live Science. “But it did smell really strong.”

Another meteorite that was recently added to the Field Museum’s collection, the Aguas Zarcas from Costa Rica, or “cosmic mudball meteorite,” was said to smell like cooked Brussels sprouts. Volatile organic compounds in rocky meteorites that are abiotic — not formed by living organisms — produce these distinctive smells when they are heated or dissolved, Heck said. 

And Murchison was an especially smelly meteorite, Heck said. When he visited the town of Murchison in 2019 for the 50th anniversary of the meteorite’s landing, he spoke with people who had witnessed the event or collected fragments of the space rock. Many of them had tales to tell about the meteorite’s distinctive aroma.

“They said the whole town smelled like methylated spirits, a very strong organic smell,” Heck said. “Even those who hadn’t seen the meteorite themselves — they smelled it.”

What Did Cassini See During Its Historic Mission To Saturn?

A thrilling epoch in the exploration of our solar system came to a close today, as NASA’s Cassini spacecraft made a fateful plunge into the atmosphere of Saturn, ending its 13-year tour of the ringed planet.

“This is the final chapter of an amazing mission, but it’s also a new beginning,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate at NASA Headquarters in Washington. “Cassini’s discovery of ocean worlds at Titan and Enceladus changed everything, shaking our views to the core about surprising places to search for potential life beyond Earth.”

Telemetry received during the plunge indicates that, as expected, Cassini entered Saturn’s atmosphere with its thrusters firing to maintain stability, as it sent back a unique final set of science observations. Loss of contact with the Cassini spacecraft occurred at 7:55 a.m. EDT (4:55 a.m. PDT), with the signal received by NASA’s Deep Space Network antenna complex in Canberra, Australia. 

Earl Maize, program manager for NASA’s Cassini spacecraft, and Julie Webster, spacecraft operations team manager

Earl Maize, program manager for NASA’s Cassini spacecraft at the agency’s Jet Propulsion Lab, and Julie Webster, spacecraft operations team manager for the Cassini mission at Saturn, embrace in an emotional moment for the entire Cassini team after the spacecraft plunged into Saturn, Friday, Sept. 15, 2017.Credits: NASA/Joel Kowsky

“It’s a bittersweet, but fond, farewell to a mission that leaves behind an incredible wealth of discoveries that have changed our view of Saturn and our solar system, and will continue to shape future missions and research,” said Michael Watkins, director of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, which manages the Cassini mission for the agency. JPL also designed, developed and assembled the spacecraft.

Cassini’s plunge brings to a close a series of 22 weekly “Grand Finale” dives between Saturn and its rings, a feat never before attempted by any spacecraft.

“The Cassini operations team did an absolutely stellar job guiding the spacecraft to its noble end,” said Earl Maize, Cassini project manager at JPL. “From designing the trajectory seven years ago, to navigating through the 22 nail-biting plunges between Saturn and its rings, this is a crack shot group of scientists and engineers that scripted a fitting end to a great mission. What a way to go. Truly a blaze of glory.”

As planned, data from eight of Cassini’s science instruments was beamed back to Earth. Mission scientists will examine the spacecraft’s final observations in the coming weeks for new insights about Saturn, including hints about the planet’s formation and evolution, and processes occurring in its atmosphere.

These images shows where on Saturn NASA’s Cassini spacecraft entered the planet’s atmosphere.

This montage of images, made from data obtained by Cassini’s visual and infrared mapping spectrometer, shows the location on Saturn where the NASA spacecraft entered Saturn’s atmosphere on Sept. 15, 2017. The spacecraft entered the atmosphere at 9.4 degrees north latitude, 53 degrees west longitude.Credits: NASA/JPL-Caltech/University of Arizona

“Things never will be quite the same for those of us on the Cassini team now that the spacecraft is no longer flying,” said Linda Spilker, Cassini project scientist at JPL. “But, we take comfort knowing that every time we look up at Saturn in the night sky, part of Cassini will be there, too.”

Cassini launched in 1997 from Cape Canaveral Air Force Station in Florida and arrived at Saturn in 2004. NASA extended its mission twice – first for two years, and then for seven more. The second mission extension provided dozens of flybys of the planet’s icy moons, using the spacecraft’s remaining rocket propellant along the way. Cassini finished its tour of the Saturn system with its Grand Finale, capped by Friday’s intentional plunge into the planet to ensure Saturn’s moons – particularly Enceladus, with its subsurface ocean and signs of hydrothermal activity – remain pristine for future exploration.

While the Cassini spacecraft is gone, its enormous collection of data about Saturn – the giant planet, its magnetosphere, rings and moons – will continue to yield new discoveries for decades to come.

“Cassini may be gone, but its scientific bounty will keep us occupied for many years,” Spilker said. “We’ve only scratched the surface of what we can learn from the mountain of data it has sent back over its lifetime.”

An online toolkit with information and resources for Cassini’s Grand Finale is available at:

https://saturn.jpl.nasa.gov/grandfinale

​Watch Cassini’s final view of Saturn at:

The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. JPL, a division of Caltech in Pasadena, manages the mission for NASA’s Science Mission Directorate in Washington.

-end-

Proxima Centauri, the sun's nearest neighbor, may host a 2nd alien planet. Meet Proxima c.

The newly detected icy world remains a candidate planet for now.

An artist’s illustration of the Proxima Centauri planetary system. Portrayed on the right is the newly discovered exoplanet candidate Proxima c, which orbits the red-dwarf host star once every 5.2 Earth years. The system also includes the smaller Proxima b, on the left, a confirmed world that was discovered in 2016.An artist’s illustration of the Proxima Centauri planetary system. Portrayed on the right is the newly discovered exoplanet candidate Proxima c, which orbits the red-dwarf host star once every 5.2 Earth years. The system also includes the smaller Proxima b, on the left, a confirmed world that was discovered in 2016.(Image: © Lorenzo Santinelli)

Proxima b may not be an only child after all.

In August 2016, astronomers announced that a roughly Earth-size exoplanet circles the closest star to the sun, the red dwarf Proxima Centauri, which lies a mere 4.2 light-years from us. (For perspective, the Milky Way galaxy’s spiral disk is about 100,000 light-years wide.)

That world, called Proxima b, orbits in Proxima Centauri’s “habitable zone,” the just-right range of distances from a star where liquid water could be stable on a world’s surface. So, there’s a chance that life as we know it may have taken root in the next solar system over from us. (How good that chance is remains a matter of considerable debate, however. For example, Proxima b is tidally locked to its host star, meaning it has a hot dayside and a cold nightside. And red dwarfs are very active stars, so powerful flares may have stripped the planet’s atmosphere long ago.)

Proxima b’s discoverers analyzed “radial velocity” data gathered over multiple years by instruments called HARPS (High Accuracy Radial Velocity Planet Searcher) and UVES (Ultraviolet and Visual Echelle Spectrograph), which are installed on telescopes operated by the European Southern Observatory (ESO) in Chile. The scientists noticed that Proxima Centauri was being tugged slightly by the gravity of an orbiting planet: Proxima b.

The team, led by Guillem Anglada-Escudé of Queen Mary University London, didn’t see any signs of other worlds orbiting the red dwarf at the time, but they couldn’t rule that prospect out. And now, a new study reports that the closest exoplanet to Earth may indeed have a companion.Click here for more Space.com videos…CLOSEVolume 0%This video will resume in 12 seconds PLAY SOUND

A frigid super-Earth candidate

In the new study, which was published online today (Jan. 15) in the journal Science Advances, a team led by Mario Damasso and Fabio Del Sordo (and including Anglada-Escudé, who’s a co-author) re-examined the old HARPS and UVES observations, along with a series of new HARPS measurements. 

The researchers subjected the data to new analyses that tracked Proxima Centauri’s light spectrum over time, looking for regular oscillations that could betray the presence of an undiscovered planet. (Damasso and Del Sordo also presented their results at the Breakthrough Discuss conference in Berkeley, California, last April, before the paper had been accepted for publication.)

There was a lot of information to go through; the combined HARPS and UVES measurements spanned about 17.5 years.

This painstaking work unearthed a possible planet called Proxima c, which is at least 6 times more massive than Earth and may therefore be a type of world known as a super-Earth. Proxima c completes one lap around Proxima Centauri every 5.2 Earth years, making it a poor prospect for life as we know it.

“Given the low luminosity of the host star and the orbital radius of the planet, it receives a very low insolation,” said Damasso, who’s based at the Astrophysical Observatory of Turin, which is run by Italy’s National Institute for Astrophysics.

“A simple estimate of the equilibrium temperature gives T~40 K,” Damasso told Space.com via email. (Forty degrees K, or Kelvin, is equivalent to minus 388 degrees Fahrenheit, or minus 233 Celsius.)

But Damasso and Del Sordo both stressed that habitability is a difficult topic to address, given the many factors that go into it and the paucity of information available about most exoplanetary systems. For example, to gauge a world’s true life-supporting ability, you’d need to know how thick its atmosphere is and what the air is made of, as well as how active its star is (as the Proxima b example shows). 

In addition, worlds that don’t lie in the traditional “habitable zone” may still be able to harbor life as we know it. After all, the Jupiter moon Europa and Saturn satellite Enceladus are covered by icy shells, but both possess huge subsurface oceans of liquid water.

In addition, the habitability talk generally assesses a world’s suitability for Earth-like life, and there’s certainly no guarantee that aliens in other systems share our biochemistry.

“I am convinced there are so many unknown scenarios to be discovered about planetary features that go beyond our imagination,” Del Sordo, who’s based at the University of Crete, told Space.com via email. “But at the moment this conviction has nothing to do with science; it is only my personal point of view.”

More work needed

Proxima c remains a candidate for now, Damasso and Del Sordo emphasized; confirming its existence will require additional information. That information will ideally come from the European Space Agency’s star-mapping Gaia spacecraft, the researchers said.

“According to our study, if Gaia will deliver the data with the expected quality, and in the absence of any unknown impediment, the detection can be reliably confirmed or dismissed,” Damasso said.

The study team is also assessing how additional HARPS and UVES data might aid the confirmation effort, he added. In addition, the researchers are considering searching for Proxima c via direct imaging — in particular, in photos captured by SPHERE (Spectro-Polarimetric High-contrast Exoplanet REsearch), a tool installed on ESO’s Very Large Telescope in Chile.Advertisement

“This is really a challenging task, almost impossible for a blind search with the present capabilities, but having details about the candidate’s orbit can help looking for the planet’s reflected light in the right places,” Damasso said.

The difficulty of directly imaging Proxima c means that the lack of a detection by SPHERE would not be a significant strike against the candidate planet’s existence, Del Sordo added. And the team’s data do suggest that it’s probably there, waiting to be found.

“According to our calculation, at the moment the two-planet model is five times more probable than the one-planet model to explain the data,” Del Sordo said. “It means it is 83% probable planet c exist[s]. Of course, follow-up will be crucial, as Mario said.”

Top-secret UFO files could 'gravely damage' US national security if released, Navy says

The truth is out there… but you’re still not allowed to see it.

In 2017, a video of the Nimitz UFO encounter was publicly released.This infamous video of the USS Nimitz UFO encounter may not be the only one out there…(Image: © To The Stars Academy of Arts & Science)

In November 2004, several U.S. Navy pilots stationed aboard the USS Nimitz encountered a Tic-Tac-shaped UFO darting and dashing over the Pacific Ocean in apparent defiance of the laws of physics. Navy officials dubbed the strange craft an “unidentified aerial phenomenon,” but they have remained mum on what, exactly, that phenomenon could’ve been. Now, unsurprisingly to anyone who’s ever considered making a hat out of tinfoil, the military has confirmed they know more than they’re letting on.

In response to a recent Freedom of Information Act (FOIA) request, a spokesperson from the Navy’s Office of Naval Intelligence (ONI) confirmed that the agency possesses several top-secret documents and at least one classified video pertaining to the 2004 UFO encounter, Vice reported. ADVERTISING

According to the ONI spokesperson, these documents were either labeled “SECRET” or “TOP SECRET” by the agencies that provided them, and that sharing the information with the public “would cause exceptionally grave damage to the National Security of the United States.”

These top-secret files included several “briefing slides” about the incident, provided to the ONI by an unnamed agency. (Because ONI officials did not classify the slides personally, they are unable to declassify them, the spokesperson added). 

The ONI also admitted to possessing at least one video of unknown length, classified as “secret” by the Naval Air Systems Command (NAVAIR). ONI didn’t reveal whether this footage is the same 1-minute video that was leaked online in 2007 and widely released by The New York Times in 2017. However, in November 2019, several naval officers who witnessed the incident aboard the Nimitz told Popular Mechanics that they had seen a much longer video of the encounter that was between 8 and 10 minutes long. These original recordings were promptly collected and erased by “unknown individuals” who arrived on the ship by helicopter shortly after the incident, one officer said.

Luis Elizondo, a former Pentagon staffer who helped make the Navy video public, told Vice that “people should not be surprised by the revelation that other videos exist and at greater length.”

The FOIA request, submitted in October 2019 by an independent researcher, asked for access to any nonclassified records or portions of records regarding the 2004 UFO encounter. No additional documents were mentioned in the ONI’s response besides the classified briefing and video.

A Mars sample-return mission is coming. Scientists want the public to know what to expect.

Artist's illustration of NASA's planned Mars Ascent Vehicle launching samples off the surface of the Red Planet.Artist’s illustration of NASA’s planned Mars Ascent Vehicle launching samples off the surface of the Red Planet.(Image: © NASA/JPL-Caltch)

The first pristine pieces of Mars won’t be coming down to Earth for at least another decade, but the time to start preparing society for the epic arrival is now, scientists say.

NASA’s 2020 Mars rover is scheduled to launch in July of this year and land inside the Red Planet’s 28-mile-wide (45 kilometers) Jezero Crater next February. The six-wheeled robot will do a variety of work once it gets there, but its headline task is hunting for signs of ancient Mars life. ADVERTISING

Mars 2020 will do this on the ground in Jezero, which hosted a lake and a river delta billions of years ago. The rover will also collect and cache promising samples for eventual return to Earth, where scientists in well-equipped labs around the world can scrutinize them in exacting detail for any evidence of Martian organisms.

NASA and the European Space Agency (ESA) will work together to get those samples here. The current plan, which is not yet official, envisions two key launches in 2026. These will send ESA’s Earth Return Orbiter (ERO) and NASA’s Sample Retrieval Lander (SRL) mission toward the Red Planet.

ERO will make its way to Mars orbit, whereas SRL will drop a stationary lander, the ESA-provided Sample Fetch Rover (SFR), and a small rocket called the Mars Ascent Vehicle (MAV) near the Mars 2020 landing site.

The SFR will pick up the cached Mars 2020 samples, which will be encased in sealed tubes, and haul them back to the MAV. Mars 2020 may store some of its samples on its body; if that’s the case, the NASA rover could roll over to the MAV and make a deposit as well. 

The MAV will then launch into Mars orbit, where it will deploy the container harboring the samples. The ERO will pluck this precious cargo out of the void and haul it back toward Earth, jettisoning the container once our planet is in the crosshairs. The samples will land here in 2031, if all goes according to this preliminary plan.

This touchdown will be a momentous occasion. Engineers will glory in the tremendous technological achievement — we’ve returned samples from the moon, but that’s quite a bit closer to Earth — and scientists will revel in the chance to learn a great deal about ancient Mars and, perhaps, find out whether Earth life is alone in the universe. 

(Researchers have examined Mars material before: meteorites blasted off the Red Planet by asteroid or comet strikes that ended up landing here on Earth. But those Mars rocks aren’t pristine — they endured trips through two planetary atmospheres and lots of time in deep space — and they weren’t specially chosen for their potential to host evidence of life.)

The public will doubtless be excited, too. But if the arrival catches folks off guard, there will probably be considerable fear, anxiety and confusion as well, said Sheri Klug Boonstra of Arizona State University’s Mars Space Flight Facility. So, the members of the international Mars sample-return team need to start educating and engaging laypeople about the effort now, said Klug Boonstra, a science-education specialist who’s the principal investigator of NASA’s Lucy Student Pipeline and Competency Enabler Program.

“The public has to be a major part of the equation,” she told Space.com last month at the annual fall meeting of the American Geophysical Union in San Francisco, where she gave a presentation on this very topic

For example, some people will likely worry that the samples could harbor some sort of infectious microbe that could get loose and unleash a deadly plague on humanity. The sample-return team has thought about this remote possibility, of course, and is doing its best to ensure it could never come to pass. 

After arriving on Earth, the Mars material will first be vetted at a specially constructed Sample Receiving Facility, which will be designed to prevent contamination in both directions: Nothing unwanted can get in to taint the samples, and nothing from the samples can get out into the wider world. The SRF hasn’t been built; indeed, a site for it hasn’t even been chosen yet. But the sample-return project can use existing Biosafety Level 4 labs — the most secure ones, which keep nasty viruses such as Ebola from spilling out — as a baseline, team member Tim Haltigin of the Canadian Space Agency told Space.com at the AGU meeting.

The public needs to know that such safety measures will be taken, Klug Boonstra said. And it’s also important to get across the potential scientific bounty represented by those little tubes of Mars material, she added. 

The sample-return team is still working out what engagement strategies to employ. Klug Boonstra said the project would like to organize some opt-in focus groups to learn which tacks to take — for example, if activities in schools would be particularly useful in getting the word out.

And that needs to start happening soon, she stressed. It could well take a decade to get Mars sample return fully socialized, especially since our society seems to be getting less science-literate and more sound-bite-driven.

“We don’t want to be in the position where we’re just getting the information out when the public hears that the rocks are coming back,” Klug Boonstra said.

Has the Kepler Space Telescope Discovered an Alien Megastructure?

The artist's concept shows NASA's planet-hunting Kepler spacecraft operating in a new mission profile called K2.

The artist’s concept shows NASA’s planet-hunting Kepler spacecraft operating in a new mission profile called K2.(Image: © NASA Ames/JPL-Caltech/T Pyle)

NASA’s Kepler Space Telescope is tasked with finding small, rocky worlds orbiting distant stars. However, exoplanets aren’t the only thing Kepler can detect — stellar flares, star spots and dusty planetary rings can also pop up in the mission’s observations.

By surrounding their star with swarms of energy-collecting satellites, advanced civilizations could create Dyson spheres. [Read the Full Dyson Sphere Infographic Here.]
By surrounding their star with swarms of energy-collecting satellites, advanced civilizations could create Dyson spheres. [Read the Full Dyson Sphere Infographic Here.] (Image credit: by Karl Tate, Infographics Artist)

But there’s also been speculation that Kepler may have the ability to detect more than natural phenomena; if they’re out there, Kepler may also detect the signature of artificial structures orbiting other stars. Imagine an advanced civilization that’s well up on the Kardashev scale and has the ability to harness energy directly from its star. This hypothetical alien civilization may want to construct vast megastructures, like supersized solar arrays in orbit around their host star, that could be so big that they blot out a sizable fraction of starlight as they pass in front.ADVERTISING

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When Kepler detects an exoplanet, it does so by sensing the very slight dip in starlight from a given star. The premise is simple: an exoplanet orbits in front of star (known as a “transit”), Kepler detects a slight dimming of starlight and creates a “lightcurve” — basically a graph charting the dip in starlight over time. Much information can be gleaned from the lightcurve, such as the physical size of the transiting exoplanet. But it can also deduce the exoplanet’s shape.

Normally the shape of an exoplanet isn’t particularly surprising because it’s, well, planet-shaped. It’s round. The physics of planetary formation dictate that a planetary body above a certain mass will be governed by hydrostatic equilibrium. But say if Kepler detects something that isn’t round. Well, that’s when things can get a bit weird.

For the most part, any dip in star brightness can be attributed to some kind of natural phenomenon. But what if all possibilities are accounted for and only one scenario is left? What if that scenario is this object appears to be artificial? In other words, what if it’s alien?

In a chilling article written by Ross Andersen of The Atlantic, at first glance, it seems we may be at this incredible juncture.

The research paper is thorough, describing the phenomenon, pointing out that this star is unique – we’ve seen nothing like it. Kepler has collected data on this star steadily for four years. It’s not instrumental error. Kepler isn’t seeing things; the signal is real.

“We’d never seen anything like this star,” Tabetha Boyajian, a postdoctorate researcher at Yale University and lead author, told The Atlantic. “It was really weird. We thought it might be bad data or movement on the spacecraft, but everything checked out.”

The Planet Hunters volunteers are depended on to seek out transits in Kepler’s stars in the direction of the constellation Cygnus. This is a huge quantity of data, from over 150,000 stars in Kepler’s original field of view, and you can’t beat the human eye when identifying a true dip in starlight brightness. The Planet Hunters described KIC 8462852 as “bizarre,” “interesting” and a “giant transit.” They’re not wrong.

Follow-up studies focus on two interesting transit events at KIC 8462852, one that was detected between days 788 and 795 of the Kepler mission and between days 1510 to 1570. The researchers have tagged these events as D800 and D1500 respectively.

The D800 event appears to have been a single transit causing a star brightness drop-off of 15 percent, whereas D1500 was a burst of several transits, possibly indicating a clump of different objects, forcing a brightness dip of up to 22 percent. To cause such dips in brightness, these transiting objects must be huge.

The transit data for KIC 8462852, featuring the obvious transit features D800 and D1500.
The transit data for KIC 8462852, featuring the obvious transit features D800 and D1500. (Image credit: Boyajian et al.)

The researchers worked through every known possibility, but each solution presented a new problem. For example, they investigated the possibility of some kind of circumstellar disk of dust. However, after looking for the infrared signal associated with these disks, no such signal could be seen.

Also, the star is a mature F-type star, approximately 1.5 times the size of our sun. Circumstellar disks are usually found around young stars.

The researchers also investigated the possibility of a huge planetary collision: could the debris from this smashup be creating this strange signal? The likelihood of us seeing a planetary collision is extremely low. There is no evidence in data taken by NASA’s Wide-field Infrared Survey Explorer (WISE) that a collision happened, creating a very tiny window of opportunity between WISE’s mission end and the beginning of Kepler’s mission (of a few years) for an astronomically unlikely cosmic event like this to occur.Advertisement

The only natural explanation favored by the researchers seems to focus on an intervening clump of exocomets.

“One way we imagine such a barrage of comets could be triggered is by the passage of a field star through the system,” write the researchers.

Indeed, they argue, there’s a nearby star that might have tidally disturbed otherwise dormant comets in the outermost regions of the KIC 8462852 star system. This small star is located around 1,000 AU from KIC 8462852 and whether it’s a binary partner or an interstellar visitor, its presence may have caused some cometary turmoil. Like the other scenarios, however, the exocomet explanation still falls short of being fully satisfactory.

This research paper focuses only on natural and known possible causes of the mystery transit events around KIC 8462852. A second paper is currently being drafted to investigate a completely different transit scenario that focuses around the possibility of a mega-engineering project created by an advanced alien civilization.

This may sound like science fiction, but our galaxy has existed for over 13 billion years, it’s not such a stretch of the imagination to think that an alien civilization may be out there and evolved to the point where they can build megastructures around stars.

“Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilization to build,” Jason Wright, an astronomer from Penn State University, told The Atlantic.

Indeed, hunting down huge structures that obscure the light from stars is no new thing. The Search for Extraterrestrial Technology (SETT) is one such project that does just this. Only recently, a survey of the local universe focused on the hope of detecting the waste heat generated by a technologically advanced civilization, specifically a Type II Kardashev civilization.

On the Kardashev scale, a Type II civilization has the ability to utilize all the available energy radiating from a star. Using a vast shell or series of rings surrounding a star, a Dyson sphere-like structure may be constructed. This has the effect of blotting out the star from view in visible wavelengths, but once the solar energy has been used by the alien civilization, the energy is shifted to longer wavelengths and likely lost as infrared radiation.

This recent search for aliens’ waste heat drew a blank, reaching the conclusion that as there appears to be no alien intelligence cocooning stars to harvest their heat, there’s likely no Type II civilization nearby.

But as KIC 8462852 is showing us, there may be something else out there — possibly an alien intelligence that is well on its way to becoming a Type II civilization, which is setting up some kind of artificial structure around its star.

Of course, these mystery transit events are nowhere near “proof” of an alien civilization. In fact, it’s barely evidence and a lot more work needs to be done.

The next step is to point a radio antenna at KIC 8462852, just to see whether the system is generating any artificial radio signals that could indicate the presence of something we’d define as “intelligent.” Boyajian and Wright have now teamed up with Andrew Siemion, the Director of the SETI Research Center at the University of California, Berkeley, to get a radio telescope to listen into the star and if they detect an artificial signal, they will request time on the Very Large Array (VLA) to deduce whether any radio signals from that star are the chatter of an alien civilization.

It might be a long shot, and the phenomenon is more likely a clump of comets or some other natural phenomenon that we haven’t accounted for blocking star light from view, but it’s worth investigating, especially if there really is some kind of alien intelligence building structures, or perhaps, ancient structures of a civilization long-gone, around a star only 1,500 light-years away from Earth.

TESS Satellite Discovered Its 1st World Orbiting 2 Stars

Researchers working with data from NASA’s Transiting Exoplanet Survey Satellite (TESS) have discovered the mission’s first circumbinary planet, a world orbiting two stars. The planet, called TOI 1338b, is around 6.9 times larger than Earth, or between the sizes of Neptune and Saturn. It lies in a system 1,300 light-years away in the constellation Pictor.

The stars in the system make an eclipsing binary, which occurs when the stellar companions circle each other in our plane of view. One is about 10% more massive than our Sun, while the other is cooler, dimmer and only one-third the Sun’s mass. TOI 1338b’s transits are irregular, between every 93 and 95 days, and vary in depth and duration thanks to the orbital motion of its stars.

TESS only sees the transits crossing the larger star — the transits of the smaller star are too faint to detect. Although the planet transits irregularly, its orbit is stable for at least the next 10 million years. The orbit’s angle to us, however, changes enough that the planet transit will cease after November 2023 and resume eight years later.

Let's Put A Space Station Around The Moon!

The Lunar Orbital Platform-Gateway is part of the Artemis program to return to the moon and stay. It will serve as a waypoint between Earth and the moon and a gateway to deep space and Mars missions.

The Lunar Orbital Platform-Gateway is a proposed NASA program that would bring astronauts to the moon to operate a lunar space station. The concept has generated a wealth of research and numerous political discussions since 2017, especially because NASA’s stated goal under the Trump administration is to return to the moon before going to Mars.

The hardware and mission design are still in the early stages of development, but as of mid-2018, NASA envisions a lunar outpost (supplied by Space Launch System rockets) that would hold four people. Unlike the International Space Station, the outpost would not always have a crew on board and would have the capability to perform scientific experiments autonomously. The prime contractor for the first module should be announced in 2019.

In August 2018, U.S. Vice President Mike Pence announced that astronauts could fly to the lunar space station as early as 2024; however, it’s likely that date will change as design and construction plans proceed.

In the same month as Pence’s announcement, NASA administrator Jim Bridenstine told reporters that the cost of the gateway won’t be nearly as much as the cost of the crewed Apollo missions in the 1960s. NASA’s current budget is now about 0.5 percent of annual federal funds, compared to its former height of 4.5 percent in the mid-1960s. The agency plans to begin the Gateway project without drawing on increased federal funding.

First steps to a gateway

In 2012, NASA publicly discussed the idea of a lunar station on the moon’s far side — called the Deep Space Habitat. A few years later, in 2014 and 2015, NASA began to consider the idea of “cislunar habitats” as a way to fly humans on longer missions in the 2020s. The agency envisioned a small shelter where astronauts could assemble telescopes, operate rovers and perform scientific research.

In March 2015, NASA awarded several contracts under its Next Space Technologies for Exploration Partnerships (NextSTEP) program to companies developing concepts for lunar modules. The goal was to build modules would attach to the Orion spacecraft (a deep-space vehicle under development by NASA) and allow for missions of about 60 days in duration. The agency also discussed cislunar habitats in a “Journey to Mars” report published in October 2015.

One of the earliest mentions of a lunar space station, then known as the Deep Space Gateway, was in an article published on NASA’s website in March 2017. As NASA described it at the time: “The agency is … looking to build a crew tended spaceport in lunar orbit within the first few missions that would serve as a gateway to deep space and the lunar surface. This deep space gateway would have a power bus, a small habitat to extend crew time, docking capability, an airlock, and [would be] serviced by logistics modules to enable research.”

NASA is planning a deep-space habitat around the moon called the Lunar Orbiting Platform Gateway, as the next destination for astronauts. The cis-lunar space station will be a waypoint for future missions to the moon and beyond. (Image credit: NASA)

The agency said the gateway would be useful not only for lunar orbiting missions, but also for increasing the breadth and depth of space exploration in general. “The area of space near the moon offers a true deep space environment to gain experience for human missions that push farther into the solar system, access the lunar surface for robotic missions but with the ability to return to Earth if needed in days rather than weeks or months.”

In July 2017, NASA issued a competitive request for information about the Power and Propulsion Element, the module that is expected to supply electrical power and chemical and electrical propulsion to the gateway. As a result, five study contracts were issued in November 2017.

That September, NASA and Roscosmos (the Russian space agency) signed a joint cooperation agreement to explore the moon and deep space, which included use of the gateway.

Back to the moon

NASA’s mission to return to the moon was bumped up in the agency’s priority list after President Donald Trump’s first space policy directive was announced in December 2017. Trump directed the agency to focus on returning to the moon before attempting to reach Mars (reaching Mars had been the primary goal during President Barack Obama’s administration).

Trump’s announcement was in line with a previous recommendation from the newly reconstituted National Space Council. The council, which hadn’t been active since the early 1990s, was re-formed in June 2017. Later that year, its members concluded that lunar exploration should be NASA’s primary goal.

The Deep Space Gateway was renamed the Lunar Orbital Platform-Gateway in February 2018, when NASA made its 2019 budget request. That document also suggested that the International Space Station should conclude operations in 2024 to make budgetary room for the gateway.

NASA held a Deep Space Gateway Science Workshop from Feb. 27 to March 1, 2018, in Denver, which helped the agency formulate a science plan for the lunar complex. Also in 2018, NASA launched the Revolutionary Aerospace Systems Concepts-Academic Linkages (RASC-AL) design competition for university students, which focused on developing concepts for the gateway.

The agency is also encouraging the development of international gateway partnerships, especially from the current International Space Station partners (Russia, Europe, Japan and Canada), as it formulates the concept of the gateway.

SpaceX Starship Update- Elon Musk details SpaceX progress and flight timelines

Elon Musk details SpaceX progress on latest Starship spacecraft build and flight timelines Starship, the SpaceX stainless steel behemoth set to send humans to Mars, could end up taking humans to the Moon in just five years time.

SpaceX CEO Elon Musk made the declaration back in March 2019, amid growing interest in what the company was developing at its Boca Chica facility in Texas. SpaceX Starship was pitched in its original “BFR” form back in September 2017, but the new rocket taking shape at Boca Chica had a uniquely shiny design.

It was a response to American vice president Mike Pence, who had declared at the time that NASA would return humans to the Moon within the next five years. In response to a question about whether SpaceX Starship could send humans in that same time period, Musk stated “I think so.” As development of the SpaceX Starship continues, these plans have gradually come into focus.

The holidays might be a time of slowed activity for most companies in the tech sector, but for SpaceX, it was a time to ramp production efforts on the latest SpaceX Starship prototype — “Starship serial number 1” as it’s called, according to Elon Musk . This flight design prototype of SpaceX Starship is under construction at SpaceX’s Boca Chica development facility, and Musk was in attendance over the weekend overseeing its build and assembly. In this video Engineering Today will discuss SpaceX’s latest Starship where CEO Elon Musk details SpaceX progress on this spacecraft build and flight timelines.

Let’s get started.

Origin of deep-space radio flash discovered, and it's unlike anything astronomers have ever seen

An animation shows the random appearance of fast radio bursts (FRBs) across the sky. Astronomers have discovered about 85 since 2007, and pinpointed two of them. (Credit: NRAO Outreach/T. Jarrett (IPAC/Caltech); B. Saxton, NRAO/AUI/NSF)

An animation shows the random appearance of fast radio bursts (FRBs) across the sky. Astronomers have discovered about 85 since 2007, and pinpointed two of them. (Credit: NRAO Outreach/T. Jarrett (IPAC/Caltech); B. Saxton, NRAO/AUI/NSF)

HONOLULU — Mysterious ultra-fast pinpricks of radio energy keep lighting up the night sky and nobody knows why. A newly discovered example of this transient phenomenon has been traced to its place of origin — a nearby spiral galaxy — but it’s only made things murkier for astronomers.

The problem concerns a class of blink-and-you’ll-miss-them heavenly events known as fast radio bursts (FRBs). In a few thousandths of a second, these explosions produce as much energy as the sun does in nearly a century. Researchers have only known about FRBs since 2007, and they still don’t have a compelling explanation regarding their sources.

“The big question is what can produce an FRB,” Kenzie Nimmo, a doctoral student at the University of Amsterdam in the Netherlands, said during a news briefing on Monday (Jan. 6) here at the 235th meeting of the American Astronomical Society in Honolulu, Hawaii.

Scientists were given some help in 2016, when they discovered an FRB that repeated its quick-pulsing radio tune in random bursts. All previous examples had been one-off events.

The repeating FBR was eventually traced back to a dwarf galaxy with a high rate of star formation 3 billion light-years away, Nimmo said. The galaxy contains a persistent radio source, possibly a nebula, that could explain the FRB’s origin, she added.

Astronomers have also managed to determine that three non-repeating FRBs came from distant massive galaxies with little star formation going on. This seemed to provide evidence that repeating and non-repeating FRBs arose from different types of environments, Nimmo said. But the new discovery challenges this simple story.

FRB 180916.J0158+65, as the object is known, is a repeating FRB discovered by the Canadian Hydrogen Intensity Mapping Experiment (CHIME) observatory, a radio telescope near Okanagan Falls in British Columbia that Nimmo called “the world’s best FRB-finding machine.”

Follow-up observations by a network of telescopes in Europe allowed the research team to produce a high-resolution image of the FRB’s location. This location turned out to be a medium-sized spiral galaxy like our Milky Way that is surprisingly nearby, only 500 million light-years away, making it the closest-known FRB to date. The results were published yesterday (Jan. 6) in the journal Nature.

Despite precisely locating the FRB, the team was unable to detect any radio sources in the spiral galaxy that could explain the mysterious outbursts. Even worse, this new entity seems not to fit the patterns established by previous repeating and non-repeating FRBs.

“This is completely different than the host and local environments of other localized FRBs,” Benito Marcote, a radio astronomer at the Joint Institute for VLBI European Research Infrastructure Consortium and lead author of the Nature paper, said during the news briefing.

The researchers hope that subsequent data might help them get a handle on what this FRB is telling them. But until then, they might have to continue scratching their heads over these puzzling phenomena.

NASA planet hunter finds Earth-size habitable-zone world

NASA’s Transiting Exoplanet Survey Satellite (TESS) has discovered its first Earth-size planet in its star’s habitable zone, the range of distances where conditions may be just right to allow the presence of liquid water on the surface.


This illustration of TOI 700 d is based on several simulated environments for an ocean-covered version of the planet. | Credit: NASA's Goddard Space Flight Center

This illustration of TOI 700 d is based on several simulated environments for an ocean-covered version of the planet.Credit: NASA’s Goddard Space Flight Center

NASA’s Transiting Exoplanet Survey Satellite (TESS) has discovered its first Earth-size planet in its star’s habitable zone, the range of distances where conditions may be just right to allow the presence of liquid water on the surface. Scientists confirmed the find, called TOI 700 d, using NASA’s Spitzer Space Telescope and have modeled the planet’s potential environments to help inform future observations.

The three planets of the TOI 700 system orbit a small, cool M dwarf star. TOI 700 d is the first Earth-size habitable-zone world discovered by TESS. Found by TESS and confirmed by the Spitzer space telescope TOI-700 D is third-closest potentially terrestrial, habitable-zone planet known.

TOI 700 d is one of only a few Earth-size planets discovered in a star’s habitable zone so far. Others include several planets in the TRAPPIST-1 system and other worlds discovered by NASA’s Kepler Space Telescope.

“TESS was designed and launched specifically to find Earth-sized planets orbiting nearby stars,” said Paul Hertz, astrophysics division director at NASA Headquarters in Washington. “Planets around nearby stars are easiest to follow-up with larger telescopes in space and on Earth. Discovering TOI 700 d is a key science finding for TESS. Confirming the planet’s size and habitable zone status with Spitzer is another win for Spitzer as it approaches the end of science operations this January.”

TESS monitors large swaths of the sky, called sectors, for 27 days at a time. This long stare allows the satellite to track changes in stellar brightness caused by an orbiting planet crossing in front of its star from our perspective, an event called a transit.

TOI 700 is a small, cool M dwarf star located just over 100 light-years away in the southern constellation Dorado. It’s roughly 40% of the Sun’s mass and size and about half its surface temperature. The star appears in 11 of the 13 sectors TESS observed during the mission’s first year, and scientists caught multiple transits by its three planets.

The star was originally misclassified in the TESS database as being more similar to our Sun, which meant the planets appeared larger and hotter than they really are. Several researchers, including Alton Spencer, a high school student working with members of the TESS team, identified the error.

“When we corrected the star’s parameters, the sizes of its planets dropped, and we realized the outermost one was about the size of Earth and in the habitable zone,” said Emily Gilbert, a graduate student at the University of Chicago. “Additionally, in 11 months of data we saw no flares from the star, which improves the chances TOI 700 d is habitable and makes it easier to model its atmospheric and surface conditions.”

Gilbert and other researchers presented the findings at the 235th meeting of the American Astronomical Societyin Honolulu, and three papers — one of which Gilbert led — have been submitted to scientific journals.

The innermost planet, called TOI 700 b, is almost exactly Earth-size, is probably rocky and completes an orbit every 10 days. The middle planet, TOI 700 c, is 2.6 times larger than Earth — between the sizes of Earth and Neptune — orbits every 16 days and is likely a gas-dominated world. TOI 700 d, the outermost known planet in the system and the only one in the habitable zone, measures 20% larger than Earth, orbits every 37 days and receives from its star 86% of the energy that the Sun provides to Earth. All of the planets are thought to be tidally locked to their star, which means they rotate once per orbit so that one side is constantly bathed in daylight.

A team of scientists led by Joseph Rodriguez, an astronomer at the Center for Astrophysics | Harvard & Smithsonian in Cambridge, Massachusetts, requested follow-up observations with Spitzer to confirm TOI 700 d.

“Given the impact of this discovery — that it is TESS’s first habitable-zone Earth-size planet — we really wanted our understanding of this system to be as concrete as possible,” Rodriguez said. “Spitzer saw TOI 700 d transit exactly when we expected it to. It’s a great addition to the legacy of a mission that helped confirm two of the TRAPPIST-1 planets and identify five more.”

The Spitzer data increased scientists’ confidence that TOI 700 d is a real planet and sharpened their measurements of its orbital period by 56% and its size by 38%. It also ruled out other possible astrophysical causes of the transit signal, such as the presence of a smaller, dimmer companion star in the system.

Rodriguez and his colleagues also used follow-up observations from a 1-meter ground-based telescope in the global Las Cumbres Observatory network to improve scientists’ confidence in the orbital period and size of TOI 700 c by 30% and 36%, respectively.

Because TOI 700 is bright, nearby, and shows no sign of stellar flares, the system is a prime candidate for precise mass measurements by current ground-based observatories. These measurements could confirm scientists’ estimates that the inner and outer planets are rocky and the middle planet is made of gas.

Future missions may be able to identify whether the planets have atmospheres and, if so, even determine their compositions.

While the exact conditions on TOI 700 d are unknown, scientists can use current information, like the planet’s size and the type of star it orbits, to generate computer models and make predictions. Researchers at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, modeled 20 potential environments of TOI 700 d to gauge if any version would result in surface temperatures and pressures suitable for habitability.

Their 3D climate models examined a variety of surface types and atmospheric compositions typically associated with what scientists regard to be potentially habitable worlds. Because TOI 700 d is tidally locked to its star, the planet’s cloud formations and wind patterns may be strikingly different from Earth’s.

One simulation included an ocean-covered TOI 700 d with a dense, carbon-dioxide-dominated atmosphere similar to what scientists suspect surrounded Mars when it was young. The model atmosphere contains a deep layer of clouds on the star-facing side. Another model depicts TOI 700 d as a cloudless, all-land version of modern Earth, where winds flow away from the night side of the planet and converge on the point directly facing the star.

When starlight passes through a planet’s atmosphere, it interacts with molecules like carbon dioxide and nitrogen to produce distinct signals, called spectral lines. The modeling team, led by Gabrielle Englemann-Suissa, a Universities Space Research Association visiting research assistant at Goddard, produced simulated spectra for the 20 modeled versions of TOI 700 d.

“Someday, when we have real spectra from TOI 700 d, we can backtrack, match them to the closest simulated spectrum, and then match that to a model,” Englemann-Suissa said. “It’s exciting because no matter what we find out about the planet, it’s going to look completely different from what we have here on Earth.”

TESS is a NASA Astrophysics Explorer mission led and operated by MIT in Cambridge, Massachusetts, and managed by NASA’s Goddard Space Flight Center. Additional partners include Northrop Grumman, based in Falls Church, Virginia; NASA’s Ames Research Center in California’s Silicon Valley; the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts; MIT’s Lincoln Laboratory; and the Space Telescope Science Institute in Baltimore. More than a dozen universities, research institutes and observatories worldwide are participants in the mission.

The Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Space operations are based at Lockheed Martin Space in Littleton, Colorado. Data are archived at the Infrared Science Archive housed at IPAC at Caltech. Caltech manages JPL for NASA.

The modeling work was funded through the Sellers Exoplanet Environments Collaboration at Goddard, a multidisciplinary collaboration that brings together experts to build comprehensive and sophisticated computer models to better analyze current and future exoplanet observations.

Plasma Drive Cuts Trip To Mars Dramatically

plasma propulsion engine is a type of electric propulsion that generates thrust from a quasi-neutral plasma. This is in contrast to ion thruster engines, which generate thrust through extracting an ion current from the plasma source, which is then accelerated to high velocities using grids/anodes. These exist in many forms (see electric propulsion). Plasma thrusters do not typically use high voltage grids or anodes/ cathodes to accelerate the charged particles in the plasma, but rather uses currents and potentials which are generated internally in the plasma to accelerate the plasma ions. While this results in a lower exhaust velocity by virtue of the lack of high accelerating voltages, this type of thruster has a number of advantages. The lack of high voltage grids of anodes removes a possible limiting element as a result of grid ion erosion. The plasma exhaust is ‘quasi-neutral’, which means that ion and electrons exist in equal number, which allows simply ion-electron recombination in the exhaust to neutralise the exhaust plume, removing the need for an electron gun (hollow cathode). This type of thruster often generates the source plasma using radio frequency or microwave energy, using an external antenna. This fact, combined with the absence of hollow cathodes (which are very sensitive to all but the few noble gases) allows the intriguing possibility of being able to use this type of thruster on a huge range of propellants, from argon, to carbon dioxide, air mixtures, to astronaut urine.[1]

Plasma engines are better suited for long-distance interplanetary space travel missions.[2]

In recent years, many agencies have developed several forms of plasma-fueled engines, including the European Space AgencyIranian Space Agency and Australian National University, which have co-developed a more advanced type described as a double layer thruster.[3][4] However, this form of plasma engine is only one of many types.

Recent Mars Discovery by NASA Could Be Caused by Alien Life

With Mars Methane Mystery Unsolved, Curiosity Serves Scientists a New One: Oxygen

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.

Graph showing oxygen concentration through Mars seasons

Credits: Melissa Trainer/Dan Gallagher/NASA Goddard

“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 CObreaks 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.”

Methane and oxygen trends on Mars

Credits: Melissa Trainer/Dan Gallagher/NASA Goddard

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.

Image of Mars from Viking lander 1

Sunset at the Viking Lander 1 site, 1976.Credits: NASA/JPLView image here

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.”

NASA maps inner Milky Way, sees cosmic 'candy cane'


This image of the inner galaxy color codes different types of emission sources by merging microwave data (green) mapped by the Goddard-IRAM Superconducting 2-Millimeter Observer (GISMO) instrument with infrared (850 micrometers, blue) and radio observations (19.5 centimeters, red). Where star formation is in its infancy, cold dust shows blue and cyan, such as in the Sagittarius B2 molecular cloud complex. Yellow reveals more well-developed star factories, as in the Sagittarius B1 cloud. Red and orange show where high-energy electrons interact with magnetic fields, such as in the Radio Arc and Sagittarius A features. An area called the Sickle may supply the particles responsible for setting the Radio Arc aglow. Within the bright source Sagittarius A lies the Milky Way's monster black hole. The image spans a distance of 750 light-years. | Credit: NASA's Goddard Space Flight Center

This image of the inner galaxy color codes different types of emission sources by merging microwave data (green) mapped by the Goddard-IRAM Superconducting 2-Millimeter Observer (GISMO) instrument with infrared (850 micrometers, blue) and radio observations (19.5 centimeters, red). Where star formation is in its infancy, cold dust shows blue and cyan, such as in the Sagittarius B2 molecular cloud complex. Yellow reveals more well-developed star factories, as in the Sagittarius B1 cloud. Red and orange show where high-energy electrons interact with magnetic fields, such as in the Radio Arc and Sagittarius A features. An area called the Sickle may supply the particles responsible for setting the Radio Arc aglow. Within the bright source Sagittarius A lies the Milky Way’s monster black hole. The image spans a distance of 750 light-years.Credit: NASA’s Goddard Space Flight Center

A feature resembling a candy cane appears at the center of this colorful composite image of our Milky Way galaxy’s central zone. But this is no cosmic confection. It spans 190 light-years and is one of a set of long, thin strands of ionized gas called filaments that emit radio waves.

This image includes newly published observations using an instrument designed and built at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Called the Goddard-IRAM Superconducting 2-Millimeter Observer (GISMO), the instrument was used in concert with a 30-meter radio telescope located on Pico Veleta, Spain, operated by the Institute for Radio Astronomy in the Millimeter Range headquartered in Grenoble, France.

“GISMO observes microwaves with a wavelength of 2 millimeters, allowing us to explore the galaxy in the transition zone between infrared light and longer radio wavelengths,” said Johannes Staguhn, an astronomer at Johns Hopkins University in Baltimore who leads the GISMO team at Goddard. “Each of these portions of the spectrum is dominated by different types of emission, and GISMO shows us how they link together.”

GISMO detected the most prominent radio filament in the galactic center, known as the Radio Arc, which forms the straight part of the cosmic candy cane. This is the shortest wavelength at which these curious structures have been observed. Scientists say the filaments delineate the edges of a large bubble produced by some energetic event at the galactic center, located within the bright region known as Sagittarius A about 27,000 light-years away from us. Additional red arcs in the image reveal other filaments.

“It was a real surprise to see the Radio Arc in the GISMO data,” said Richard Arendt, a team member at the University of Maryland, Baltimore County and Goddard. “Its emission comes from high-speed electrons spiraling in a magnetic field, a process called synchrotron emission. Another feature GISMO sees, called the Sickle, is associated with star formation and may be the source of these high-speed electrons.”

Two papers describing the composite image, one led by Arendt and one led by Staguhn, were published on Nov. 1 in the Astrophysical Journal.

The image shows the inner part of our galaxy, which hosts the largest and densest collection of giant molecular clouds in the Milky Way. These vast, cool clouds contain enough dense gas and dust to form tens of millions of stars like the Sun. The view spans a part of the sky about 1.6 degrees across — equivalent to roughly three times the apparent size of the Moon — or about 750 light-years wide.

To make the image, the team acquired GISMO data, shown in green, in April and November 2012. They then used archival observations from the European Space Agency’s Herschel satellite to model the far-infrared glow of cold dust, which they then subtracted from the GISMO data. Next, they added, in blue, existing 850-micrometer infrared data from the SCUBA-2 instrument on the James Clerk Maxwell Telescope near the summit of Maunakea, Hawaii. Finally, they added, in red, archival longer-wavelength 19.5-centimeter radio observations from the National Science Foundation’s Karl G. Jansky Very Large Array, located near Socorro, New Mexico. The higher-resolution infrared and radio data were then processed to match the lower-resolution GISMO observations.

The resulting image essentially color codes different emission mechanisms.

Blue and cyan features reveal cold dust in molecular clouds where star formation is still in its infancy. Yellow features, such as the Arches filaments making up the candy cane’s handle and the Sagittarius B1 molecular cloud, reveal the presence of ionized gas and show well-developed star factories; this light comes from electrons that are slowed but not captured by gas ions, a process also known as free-free emission. Red and orange regions show areas where synchrotron emission occurs, such as in the prominent Radio Arc and Sagittarius A, the bright source at the galaxy’s center that hosts its supermassive black hole.

Satellite Images Show Australia's Devastating Wildfires from Space

The Australian wildfires can be viewed in incredible detail via NASA’s Worldview tool.

The Worldview tool from NASA's Earth Observing System Data and Information System (EOSDIS) shows this scene on Jan. 2, 2019, as wildfires continue in their intensity along the southeastern coast of Australia.
The Worldview tool from NASA’s Earth Observing System Data and Information System (EOSDIS) shows this scene on Jan. 2, 2019, as wildfires continue in their intensity along the southeastern coast of Australia.  (Image credit: NASA EOSDIS)

Satellites in space can spot changes to Earth’s climate, and they are providing frightening bird’s-eye views of the devastating consequences of global warming. 

The wildfires raging in the Australian states of New South Wales and Victoria began in November 2019, and they continue to pose severe safety and environmental problems. NBC News reported that thousands of Australians fled their homes on New Year’s Eve (Dec. 31), seeking refuge near the oceanside. On Thursday (Jan. 2) NBC News also reported that New South Wales declared a weeklong state of emergency, making this the third time an emergency period has been announced since the fires began. 

“My last day of the decade felt like the apocalypse,” Sydney-based photojournalist Matt Abbott tweeted on Dec. 31. Abbott, who is covering the wildfires for The New York Times, added: “Been covering the Australian bushfires for the last 6 weeks, but haven’t seen anything like yesterday’s fire that decimated the town of Conjola, NSW.”

My last day of the decade felt like the apocalypse. Been covering the Australian bushfires for the last 6 weeks, but haven’t seen anything like yesterdays fire that decimated the town of Conjola, NSW. #bushfirecrisis #AustralianBushfires #NSWisburning work for @nytimes

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Information from NASA satellites can teach scientists about the lingering consequences of these events, like the production of dangerous gases such as carbon monoxide. 

NASA operates a group of 26 satellites collectively known as the Earth Observing System (EOS), and its flagship satellite, a bus-sized spacecraft named Terra, hit its 20-year mark in space in December 2019. Other NASA satellites, like Aqua and Suomi NPP, also contribute data to EOS, a mission tasked with taking global measurements of the air, land and water to help scientists learn how those systems fit together and morph over time. 

The Worldview tool from NASA’s EOS Data and Information System transforms satellite data into an interactive page with over 900 imagery layers. You can view current natural disasters, like the Australian wildfires, on Worldview by date and information layer (such as thermal anomalies, borders and place labels). You can also watch an animation of activity by selecting a time range. 

A look at Australia’s surface starting in October 2019 shows the astounding evolution of wildfires as they multiplied and spewed smoke across Australia’s eastern shore. 

A severe drought in October 2019 primed the country for the destruction that’s still occurring. More than 100 fires raged over the next several months. By Dec. 12, the wildfires in Australia’s New South Wales had scourged an area of about 10,000 square miles (27,000 square kilometers), according to NASA representatives in a description of satellite imagery. 

The wildfires are raging on Australia’s eastern coast, exposing many communities, including Sydney, to hazardous pollution levels. The Measurements of Pollution in the Troposphere instrument on the Terra satellite found that the region is blanketed by abnormally high levels of carbon monoxide, an odorless and dangerous gas that’s released by the burning of plants and fossil fuels. 

This map depicts measurements of outgoing longwave radiation in November 2019. The data on Australia's heat emission comes from the Clouds and the Earth's Radiant Energy System on board NASA's Terra satellite.
This map depicts measurements of outgoing longwave radiation in November 2019. The data on Australia’s heat emission comes from the Clouds and the Earth’s Radiant Energy System on board NASA’s Terra satellite. (Image credit: EOS-Terra/NASA)

The fires have been particularly damaging to eucalyptus forests. The forests exist in both dry and rainy regions, and both climates are vulnerable to the wildfires for unique reasons. Eucalyptus plants that thrive in dry areas have oil-rich leaves that can easily ignite during a fire, according to a NASA description of the EOS imagery. Fires do help these plants release their seeds, but the dry season in October was so intense that it limited seed germination. Rainforest eucalyptus species, on the other hand, are not accustomed to fires. The ecosystem can’t bounce back the way a dry eucalyptus forest could under milder conditions. Unable to tolerate the flames, most of these rainforest plants die under these extreme conditions.

An instrument on NASA’s Tropical Rainfall Measuring Mission satellite observed the unusually hot and dry conditions of November 2019 that fueled the wildfires. The sensor, called the Clouds and the Earth’s Radiant Energy System,  measures the heat emitted back into space. The instrument measured how the sun’s radiation was absorbed, emitted and reflected by Earth’s surface during the first month of the wildfires. 

The flames destroy forests and make the air unbreathable for humans, but they also harm the animals that live there. “Browsing animals like kangaroos are driven out by fire for a short time, and the heat treatment of soil reduces the number of plant-eating insects and soil organisms during the early growth period,” Ayesha Tulloch, a conservation biologist at the University of Sydney, said in a NASA image description.Advertisement

This animation is a model of where the black smoke from the raging Australian wildfires is traveling. It's based off of the GEOS forward processing (GEOS FP) model, which combines information from satellite, aircraft and ground-based observation systems and uses data such as air temperature, moisture levels and wind information to project the plume's behavior.
This animation is a model of where the black smoke from the raging Australian wildfires is traveling. It’s based off of the GEOS forward processing (GEOS FP) model, which combines information from satellite, aircraft and ground-based observation systems and uses data such as air temperature, moisture levels and wind information to project the plume’s behavior. (Image credit: GEOS FP/NASA GSFC)

Many koalas have also been affected, or even killed, by these fires. “But the range of the koala covers most [of] the east coast of Australia,” Tulloch said. “Relative to its range, the fires are relevant to only a very small proportion of the existing koala population in Australia.”

An animation made using the GEOS forward processing (GEOS -FP) model depicts the high levels of black carbon emitted by the wildfires in early November 2019, which then blew through the atmosphere and across the Pacific Ocean. Smoke plumes have risen as high as 7 to 8 miles (12 to 13 km) into the sky, which is unusually high for wildfires, according to a NASA description of the animation. 

Hoag's Object is a Cosmic Mystery

Hoag’s Object is a non-typical galaxy of the type known as a ring galaxy.

The galaxy is named after Arthur Hoag who discovered it in 1950 and identified it as either a planetary nebula or a peculiar galaxy with eight billion stars, spanning roughly 100,000 light years.

Characteristics

A nearly perfect ring of young hot blue stars circles the older yellow nucleus of this ring galaxy c. 600 million light-years away in the constellation Serpens. The diameter of the 6 arcsecond inner core of the galaxy is about 17±0.7 kly (5.3±0.2 kpc) while the surrounding ring has an inner 28″ diameter of 75±3 kly (24.8±1.1 kpc) and an outer 45″ diameter of 121±4 kly (39.9±1.7 kpc).[2] The galaxy is estimated to have a mass of 700 billion suns.[7] By way of comparison, the Milky Way galaxy has an estimated diameter of 150-200 kly and consists of between 100 and 500 billion stars and a mass of around 1.54 trillion suns. 

Hoag’s Object, taken by the Hubble Space Telescope in July 2001

The gap separating the two stellar populations may contain some star clusters that are almost too faint to see. Though ring galaxies are rare, another more distant ring galaxy (SDSS J151713.93+213516.8) can be seen through Hoag’s Object, between the nucleus and the outer ring of the galaxy, at roughly the one o’clock position in the image shown here.

Noah Brosch and colleagues showed that the luminous ring lies at the inner edge of a much larger neutral hydrogen ring.

History and formation

Even though Hoag’s Object was clearly shown on the Palomar Star Survey, it was not included in either the Morphological Catalogue of Galaxies, the Catalogue of Galaxies and Clusters of Galaxies, or the catalogue of galactic planetary nebulae.

In the initial announcement of his discovery, Hoag proposed the hypothesis that the visible ring was a product of gravitational lensing. This idea was later discarded because the nucleus and the ring have the same redshift, and because more advanced telescopes revealed the knotty structure of the ring, something that would not be visible if the ring were the product of gravitational lensing.

Many of the details of the galaxy remain a mystery, foremost of which is how it formed. So-called “classic” ring galaxies are generally formed by the collision of a small galaxy with a larger disk-shaped galaxy. This collision produces a density wave in the disk that leads to a characteristic ring-like appearance. Such an event would have happened at least 2–3 billion years in the past, and may have resembled the processes that form polar-ring galaxies. However, there is no sign of any second galaxy that would have acted as the “bullet”, and the likely older core of Hoag’s Object has a very low velocity relative to the ring, making the typical formation hypothesis quite unlikely. Observations with one of the most sensitive telescopes have also failed to uncover any faint galaxy fragments that should be discoverable in a collision scenario. However, a team of scientists that analyze the galaxy admits that “if the carnage happened more than 3 billion years ago, there might not be any detritus left to see.”

Noah Brosch suggested that Hoag’s Object might be a product of an extreme “bar instability” that occurred a few billion years ago in a barred spiral galaxy. Schweizer et al claim that this is an unlikely hypothesis because the nucleus of the object is spheroidal, whereas the nucleus of a barred spiral galaxy is disc-shaped, among other reasons. However, they admit evidence is somewhat thin for this particular dispute to be settled satisfactorily.

A few other galaxies share the primary characteristics of Hoag’s Object, including a bright detached ring of stars, but their centers are elongated or barred, and they may exhibit some spiral structure. While none match Hoag’s Object in symmetry, this handful of galaxies are known to some as Hoag-type galaxies.[15][16]

The Mystery of the Antikythera Mechanism

More than 21 centuries ago, a mechanism of fabulous ingenuity was created in Greece, a device capable of indicating exactly how the sky would look for decades to come — the position of the moon and sun, lunar phases and even eclipses. But this incredible invention would be drowned in the sea and its secret forgotten for two thousand years.

This video is a tribute from Swiss clock-maker Hublot and film-maker Philippe Nicolet to this device, known as the Antikythera Mechanism, or the world’s “first computer”. The fragments of the Mechanism were discovered in 1901 by sponge divers near the island of Antikythera. It is kept since then at the National Archaeological Museum in Athens, Greece. For more than a century, researchers were trying to understand its functions. Since 2005, a pluridisciplinary research team, the “Antikythera Mechanism Research Project”, is studying the Mechanism with the latest high tech available.

The results of this ongoing research has enabled the construction of many models. Amongst them, the unique mechanism of a watch, designed by Hublot as a tribute to the Mechanism, is incorporating the known functions of this mysterious and fascinating ancient Mechanism. A model of the Antikythera Mechanism, built by the Aristotle University in Greece, together with the mechanism of the watch and this film in 3D are featuring in an exhibition about the Mechanism that is taking place in Paris, at the Musée des Arts et Métiers.

The original fragments of the Mechanism, its main models and the watch designed by Hublot are on display at the National Archaeological Museum in Athens, Greece.

There is a nice working virtual replica of the Antikythera mechanism on the Apple App. store. You can rotate it, pinch zoom and set it. Have not seen if for Android however. https://apps.apple.com/…/antikythera-mechanism/id989574753

NASA TO SEND ROBOT TO MARS TO EXAMINE POSSIBLE ALIEN FOSSILS

Unnamed rover will also explore how we might be able to live on the red planet

Nasa has nearly finished building a robot that will explore the surface of Mars – and examine the possibility that alien fossils are there waiting to be found.

The space agency hopes that the 2020 rover can find evidence of past life on the planet, as well as helping to discover how possible it could be that humans will live there in the future.

The Mars 2020 rover will receive its official name next year, but Nasa has shown it off to the world during an event for the media that showed the robot was nearing completion.

In February, it will ship the rover to Florida’s Kennedy Space Center where its three sections will be fully assembled. A July launch will send the rover to a dry lake bed on Mars that is bigger than the island of Manhattan.

The four-wheeled, car-sized rover will scour the base of Mars’ Jezero Crater, an 820-foot-deep (250-meter-deep) crater thought to have been a lake the size of Lake Tahoe, once the craft lands in February 2021. The crater is believed to have an abundance of pristine sediments some 3.5 billion years old that scientists hope will hold fossils of Martian life.  00:14 / 00:14TOP ARTICLES4/6READ MORERon Saunders: Football mana

Gun-toting humanoid robot sent into space

“The trick, though, is that we’re looking for trace levels of chemicals from billions of years ago on Mars,” Mars 2020 deputy project manager Matt Wallace told Reuters. The rover will collect up to 30 soil samples to be picked up and returned to Earth by a future spacecraft planned by NASA.

“Once we have a sufficient set, we’ll put them down on the ground, and another mission, which we hope to launch in 2026, will come, land on the surface, collect those samples and put them into a rocket, basically,” Wallace said. Humans have never before returned sediment samples from Mars.

The findings of the Mars 2020 research will be crucial to future human missions to the red planet, including the ability to make oxygen on the surface of Mars, Wallace said. The Mars 2020 Rover is carrying equipment that can turn carbon dioxide, which is pervasive on Mars, into oxygen for breathing and as a propellant.

If successful, Mars 2020 will mark NASA’s fifth Martian rover to carry out a soft landing, having learned crucial lessons from the most recent Curiosity rover that landed on the planet’s surface in 2012 and continues to traverse a Martian plain southeast of the Jezero Crater.

The Soviet Union is the only other country to successfully land a rover on Mars. China and Japan have attempted unsuccessfully to send orbiters around Mars, while India and Europe’s space agency have successfully lofted an orbiter to the planet.

Additional reporting by Reuters

Rogue Ice Moon Could Be Spilling Its Guts All Over 'Alien Megastructure' Star

An older NASA illustration shows a disintigrating planet orbiting Tabby's star.

An older NASA illustration shows a disintigrating planet orbiting Tabby’s star.(Image: © NASA/JPL/Caltech)

Back in 2016, headlines all over the world blared with news of a possible “alien megastructure” detected orbiting a distant Milky Way star. Now, a team of Columbia University astrophysicists has offered up an explanation for the star’s strange behavior that doesn’t involve any little green men.

The “alien” point of light in the sky is known as Tabby’s star, which was named after Tabetha Boyajian, the Louisiana State University astrophysicist who in 2015 first noticed the unusual patterns in its starlight that others initially attributed to alien construction projects. Boyajian noticed that the star tended to dip in brightness at odd intervals, sometimes slightly and sometimes by significant fractions of its total light. It was also slowly losing brightness over time. She later called it in a TED Talk the “most mysterious star in the universe” because no straightforward astrophysical theory could explain the dimming pattern —  though she also expressed skepticism about suggestions that the dimming was the result of a “megastructure” constructed around the star by an advanced civilization.

Astronomers have since offered a number of alternative explanations for the weird light from the star, which is about 1,500 light-years away in space and known formally as KIC 8462852. They range from swarms of comets to “avalanche-like magnetic activity” within the star. Boyajian conducted follow-up research that showed that the dimming is specific to certain light frequencies, which could be explained if a cloud of dust were responsible, scientists have suggested. This new research explains how that dust might have gotten there.

The new theory from the Columbia team resembles the plot of a disaster film more than a science-fiction space opera. They built on earlier work showing that whatever’s causing the dimming is likely locked in an irregular, eccentric orbit around the star. They showed that a disintegrating, orphaned ice moon following such a path could explain the strange dimming.

“It’s likely outgassing water or some other volatile material,” said Brian Metzger, one of the authors of the new paper.

Over the course of millions of years, that material would form an irregular cloud around the star along the orphaned moon’s eccentric orbit, he told Live Science, adding that such a cloud would periodically block some of the star’s light from reaching Earth — just like the effect originally attributed to a Dyson sphere megastructure.

They suspect an orphaned moon, as opposed to a planet, is off-gassing the cloud, because it’s difficult to explain how an icy planet could end up in that irregular orbit in the first place. Based on our own solar system, he said, scientists know that solid, rocky bodies tend to make up the inner parts of a system, while bigger, gaseous planets dominate the outer system. And those planets are often orbited by icy moons.

Metzger and his colleagues described orbital calculations in which a planet like Jupiter, orbited by large moons and following an eccentric orbit, gets knocked (perhaps by another nearby star) into a collision course with its host star. As it falls to its doom, the star would rip those moons from their orbits. Most of the moons would fall into the star or fly out of the system, they showed, but in about 10% of all cases, a moon would end up in an eccentric orbit. And, critically, that orbit would likely place the moon within its star’s “ice line” — the point within which the star’s radiation would blast ice off the moon’s surface.

If the moon were made up of the right materials, they wrote, it would start to break apart due to the increased radiation of its new, closer orbit, spilling that material into interplanetary space like a gargantuan comet. And even though we’d never see the moon with our existing telescopes, that spilled material would form a cloud of dust and gas big enough to block Tabby’s star’s light in strange and unpredictable ways. Over time, the star would appear to get dimmer and dimmer, just like Tabby’s star, as the total amount of dust in its orbit increased.

Nothing’s certain, of course. Metzger said it’s still possible some other phenomenon is creating the effect. But this moon theory offers a compelling explanation for a distant flickering once chalked up (at least in the popular press) to aliens.

The paper, available as a draft online in the preprint journal arXiv, will be published in a forthcoming issue of the journal Monthly Notices of the Royal Astronomical Society.

China's Huge Long March 5 Rocket Returns to Flight in Dazzling Nighttime Launch

It’s the third Long March 5 ever to fly.

China’s biggest rocket, the Long March 5, returned to flight for the first time since a 2017 failure Friday (Dec. 27) in a dazzling nighttime launch for the Chinese space program

The Long March 5 Y3 rocket lifted off at 8:45 p.m. Beijing Time carrying the experimental Shijian 20 communications satellite into a geosynchronous orbit. The satellite, which weighs a reported 8 metric tons, is China’s heaviest and most advanced satellite to date, according to state media reports.

The successful launch is the first Long March 5 since a first-stage booster failure in 2017 destroyed the Shijian 18 satellite. The failure prompted redesigns in the rocket’s first-stage engines, which led to a two-year gap between missions. The first Long March 5 rocket lifted off in 2016.

Video: Watch China’s Long March 5 Return to Space in Stunning Launch
More: 
This is the 1st Photo of China’s Mars Explorer Launching in 2020

China's massive heavy-lift Long March 5 rocket returns to flight in a dazzling nighttime launch from the Wenchang Space Launch Center on Hainan Island.
China’s massive heavy-lift Long March 5 rocket returns to flight in a dazzling nighttime launch from the Wenchang Space Launch Center on Hainan Island. (Image credit: China Aerospace Science and Technology Corporation)

The Long March 5 is an essential booster for China’s space ambitions. The heavy-lift booster will be the one to launch China’s space station modules into orbit, as well as a Mars lander in 2020 and the Chang’e 5 moon sample-return mission

China is also expected to use a version of the Long March 5, called the Long March 5B, to launch a new crewed spacecraft — the successor to its current Shenzhou crew capsule. 

The rocket stands 184 feet (56 meters) tall and weighs nearly 2 million lbs. (867,000 kilograms) at liftoff. It is capable of carrying payloads of up to 55,000 lbs. (25,000 kilograms) into low Earth orbit. It can haul up  31,000 lbs. (14,000 kg) to a higher geostationary transfer orbit.

The Shijian 20 satellite (its name means “Practice”) is designed to be a high-throughput communications satellite “capable of delivering 1 Tbps [1 terabute per second] bandwidth for ultrafast speeds,” Chinese space officials said according to the state-run Xinhua news agency.  

Shijian 20 is also expected to test a laser communications payload for future missions, as well as new ion thrusters for propulsion.