NASA’s Lunar Reconnaissance Orbiter snapped this photo of the Chang’e 3 site from 31 miles up on Feb. 17. The Yutu rover’s tracks can be followed clockwise around the lander to its current location. Image width about 656 feet (200-m). Click to enlarge. Credit: NASA/Goddard/Arizona State University
Instead of photos taken by China’s lunar rover Yutu and Chang’e 3 lander, we’re going to look at images taken ofthem by NASA’s Lunar Reconnaissance Orbiter (LRO). The orbiter’s amazing camera and 31-mile-high orbit enables fantastic resolution of the moon’s surface. Consider that the lander measures only 4.9 feet (1.5-m) across and yet it – and the smaller rover – stand out clearly against the rugged moonscape.
Animation of the above four LROC NAC images (short for Lunar Reconnaissance Orbiter Camera, Narrow Angle Camera). Credit: NASA/Goddard/Arizona State University
LRO photographed the scene on Dec. 25, 2013 and again on Jan. 21 and Feb. 17 this year. You can see how the lighting changed between the photographs in the animation which also includes a view of the landing site taken July 2009 before the probe arrived.
Here you can relate the “on the ground” perspective taken by the Chang’e 3 lander with the orbital view by LRO. Credit: CNSA (top) and NASA
You can clearly see the rover’s track around the Chang’e 3 lander. During its first lunar day, it rolled off the lander and drove to the right in a clockwise direction; by the end of the first day, equal to about two Earth weeks, Yutu had traveled approximately 100 feet (30 meters) south of the lander.
LRO slewed 54 degrees to the east on Feb. 16, 2014, to allow the LROC instrument to snap a dramatic oblique view of the Chang’e 3 site (arrow). Crater in front of lander is about 1,476 feet (450 m) in diameter. Click to enlarge. Credit: NASA/Goddard/Arizona State University
After the two-week lunar night, Yutu woke up at sunrise and drove an additional 56 feet (17 meters) back toward the lander. At the onset of the next night it developed problems folding in its solar panels, preventing the rover from keeping its equipment warm during long and bitter cold night. If that wasn’t enough, a mechanical problem now prevents it from moving. Yet somehow Yutu’s camera and several other instruments still work.
Or they did. We’ll soon find out when Chinese mission control wakes up the lander and rover to open their 4th lunar day sometime on March 10-11.
Tyche, a hypothetical large planet, was proposed to account for the regular pattern of biological extinctions across Earth’s history. It was thought that a large planet or small star hiding out far from the sun could sweep through bands of comets in its orbit, periodically sending flurries of them hurtling our way. Data from WISE nixed the idea.
Just two days ago a reader asked whether NASA’s Wide-field Infrared Survey Explorer (WISE) had found any sign of a hypothesized companion to the sun dubbed “Planet X” also known as “Nemesis”, “Tyche” and “Nibiru”. After searching through hundreds of millions of images and turning up no sign of the object, it looks like we can finally put the idea to bed.
The third closest star system to the sun, called WISE J104915.57-531906, is at the center of the larger image, which was taken by NASA’s Wide-field Infrared Survey Explorer (WISE). Credit: NASA/JPL/Gemini Observatory/AURA/NSF
WISE swept the sky once in 2010 and again in early 2011. Objects close to us appear to move faster than distant objects when viewed over time. Nearby stars appear to move more quickly across the sky than distant ones much like a low-flying plane appears to zoom by compared to the same plane flying at high altitude.
By comparing images taken by WISE six months apart, astronomers have found thousands of stars and brown dwarfs in our sun’s “backyard” by flagging those moving fastest.
All told, WISE turned up 3,525 stars and brown dwarfs within 500 light-years of our sun, objects totally overlooked or unseen by ground-based optical telescopes. Take the pair of brown dwarfs hidden practically under our noses only 6.5 light years away. Called WISE J104915.57-531906, it’s the third closest star system to Earth and the closest discovered since astronomer E.E. Barnard spotted “Barnard’s Star” in 1916 nearly a hundred years ago.
Data from WISE has found no evidence for a hypothesized body sometimes referred to as “Planet X.” The chart shows that WISE can easily spot a Jupiter-sized object out to 10,000 AU, but if one existed at 100,000 AU, it would too faint to see. Credit: Penn State University
But WISE’s two complete infrared sweeps of the sky found that no object the size of Saturn or larger exists out to a distance of 10,000 astronomical units (AU), and no object larger than Jupiter exists out to 26,000 AU or 2.4 trillion miles. One astronomical unit equals 93 million miles or Earth’s distance from the sun. Dwarf planet Pluto orbits about 40 AU from the sun.
Illustration of the WISE spacecraft orbiting Earth. The probe was put into hibernation at the end of its mission in 2011 and then re-activated late last year as NEOWISE. NEOWISE will survey for comets and asteroids. Credit: NASA/JPL-Caltech
“The outer solar system probably does not contain a large gas giant planet, or a small, companion star,” said Kevin Luhman of the Center for Exoplanets and Habitable Worlds at Penn State University, University Park, Pa., author of a paper in the Astrophysical Journal describing the results.
Meanwhile, astronomers have been sifting through the reams of WISE data since the probe wrapped up its mission in 2011. In addition to the new stars mentioned, the orbiting spacecraft captured photos of nearly 750 million asteroids, stars and galaxies. Since scientists continue to pour over the data, there’s a remote chance a Planet X might be found, but much more likely we’ll continue to find other stars never seen before in regular optical telescopes.
Click to enjoy a journey across our spacious solar system courtesy of Josh Worth.
How do you picture the solar system? Most of us imagine the eight planets as colorful balls of varying sizes moving in orbits that comfortably fit within the confines of our computer screens. But is that how it really is? Maybe as a handy reference, but the real place is far different. A new simulator that shrinks the moon to one pixel goes a long to help us appreciate its true vastness.
Is this how you picture the solar system? You’re not alone. The true scale of the real version may surprise you. Credit: ESO
In my astronomy classes, I try to convey a sense of how small the planets are compared to the abyss of space by playing the “Honey, I shrunk the planets” game. If the sun’s the size of a softball, Earth’s a sphere the size of a grain of salt (~1 mm) 38 feet away. Jupiter’s a little larger than a penny and 200 feet away, and Alpha Centauri, the nearest star beyond the sun, flickers 2,000 miles from home.
OK, that’s not bad, but maybe not visceral enough. Somehow we’d like to feel the distance, sense the emptiness. That’s where the new simulator If the Moon Were Only 1 Pixelexcels.
Planets and the sun are shown to scale in “If the Moon …” with the moon represented by a single pixel. Credit: Josh Worth
Created by Josh Worth, a graphic artist and writer from Los Angeles, the simulator uses a horizontal slider to scroll you from one end of the sun’s neighborhood to the other. You can use the scroll bar at the bottom of the page, your keyboards’ arrow or, if your mouse allows or you’re using a touch pad, move along with repeated flicks of a finger. Planets sizes are based on the moon, which Worth has shrunk down to one pixel.
I found that scrolling from Mercury to Venus to Earth took some time but was hardly taxing. It was traveling to Jupiter that blew me away. Worth entertains along the way with funny tidbits and facts, but I swear the next time I look up at Jupiter I’ll have a better appreciation of how much space separates our two worlds.
Not that you have to scroll, scroll, scroll. Just click on a planet’s icon at the top of the screen and you’ll be whisked there in a jiffy. I suggest you pour a cup and savor the journey.
he NASA/ESA Hubble Space Telescope photographed the break-up of P/2013 R3 from Oct. 29, 2013 to Jan. 14, 2014. Although fragile comet nuclei have been seen to fall apart as they approach the Sun, nothing like this breakup, which occurred in the asteroid belt, has ever been observed before. Click to enlarge. Credit: NASA/ESA/D. Jewitt (UCLA)
The Hubble Space Telescope has photographed a never-seen-before breakup of an asteroid. Named P/2013 R3 (Catalina-PanSTARRS), it was discovered last September 15 by the Catalinaand Pan-STARRS sky surveys as a faint, slightly fuzzy object. Two weeks later, the giant Keck Telescope in Hawaii took a closer look and saw not one but three separate pieces cruising along convoy-style in a dust cloud of their own making.
Animation showing the break up of P/2013 R3
By December it had crumbled into ten pieces, the four largest of which measure about 650 feet (200 meters) across or nearly two football fields apiece. The Hubble data show the fragments are drifting apart at the leisurely rate of just under 1 mile per hour (1.5 km/hr) or about the speed of someone walking while texting.
“This is a really bizarre thing to observe — we’ve never seen anything like it before,” says co-author Jessica Agarwal of the Max Planck Institute for Solar System Research, Germany. ”The break-up could have many different causes, but the Hubble observations are detailed enough that we can actually pinpoint the process responsible.”
P/2013 R3 on Oct. 22, 2013 looked very much like a comet. The individual pieces that comprise the shattered asteroid are too small to resolve in this photo. The fresh dust exposed as the asteroid fell apart shows as a faint tail. Credit: Damian Peach
Astronomers have ruled out a collision, which would have happened suddenly and sent pieces flying apart at much great speeds. Shattering from the pressure of vaporizing ices in its interior also seems unlikely given the asteroid’s distance of 298 million miles (480 million km) from the sun – believed too cold for any ice it might possess to suddenly turn to vapor and pry the body apart. Besides, if it did contain ice, P/2013 R3 wouldn’t be considered an asteroid anymore but a main belt comet, an asteroid-like object between Mars and Jupiter that occasionally flares up as a comet.
So what could be responsible for perpetrating killing off an asteroid? Scientists suspect it was YORP up to his old tricks. YORP or the Yarkovsky-O‘Keefe-Radzievskii-Paddack effect requires only the light touch of sunshine to get rolling.
This illustration shows one possible explanation for the disintegration of asteroid P/2013 R3. Sunlight absorbed unequally across the asteroid’s surface can spin up its rotation and cause it to fall apart. More details on how this happens below. Credit: NASA, ESA, D. Jewitt (UCLA), and A. Feild (STScI)
Sunlight absorbed by P/2013 R3 is re-emitted as heat. Assuming the asteroid is irregular in shape – and most are because they’re so small – some areas get hotter and give off more heat than others. The imbalance causes a torque on the asteroid, increasing its spin rate.
Hubble Space Telescope close up of P/2013 R3 breaking up as seen on Nov. 15, 2013. Although fragile comet nuclei have been observed to fall apart as they approach the sun, this is the first time an asteroid has been seen to do so. Click to enlarge. Credit: NASA/ESA/D. Jewitt (UCLA)
Many asteroids are “rubble piles” of individual objects held together by gravity rather than solid rocks. Collisions with other asteroids over the 4.5 billion year lifetime of the solar system have shattered and pulverized their interiors. Primed to fall apart, the spin-up from YORP causes the asteroid to come apart at the seams. Pieces that were loosely-bound can drift away due to centrifugal forces; fresh dust exposed creates an enveloping comet-like cloud of debris. Pretty darn cool.
Yorping the day away. Illustration showing how sunlight absorbed unevenly by an asteroid’s surface creates torque that can increase its spin rate. Illustration: Bob King
We’ve seen one other instance of an asteroid breaking to pieces when Hubble photographed the aftermath of a head-on collision between the peculiar comet-like asteroid P/2010 A2 and a smaller asteroid in January 2010. But this is the first time ever we’ve watched an asteroid fall apart of its own accord.
“This indicates that the Sun may play a large role in disintegrating these small Solar System bodies, by putting pressure on them via sunlight,” said Agarwal.
Much of P/2013′s debris, weighing in at around 200,000 tons, will spiral its way into into the sun, but a portion could one day light up Earth’s skies as a lovely meteor shower. Amazing isn’t it how nature shares its incredible stories when we pay attention.
This is where 2014 EC is today as it heads towards its close Earth flyby tomorrow. Credit: NASA/JPL
Don’t forget to look both ways. You can hardly cross the street but another asteroid comes flying by. Last night astronomers discovered a new object named 2014 EC. This one’s tiny – only 33 feet (10 meters) across or about half the size of the asteroid that blasted to bits over Chelyabinsk, Russia last February.
It zooms by Earth tomorrow March 6 around 3 p.m. CST at a distance of just 48,000 miles (77,000 km). Again, there’s no threat of a strike. Asteroids can pass very close to the planet without getting “sucked in” by gravity because they’re moving forward in their orbits at tens of thousands of miles an hour. That’s a lot of momentum.
Still, a small asteroid making a pass near Earth doesn’t get away scot-free. Much like the Voyager space probe (and others) that passed close to one planet to slingshot to the next, small asteroids passing near Earth have their orbits re-shaped by our planet’s gravity and sent on their way on a different trajectory.
Three classes of asteroids that pass near Earth or cross its orbit are named for the first member discovered — Apollo, Aten and Amor. Apollo asteroids like 2014 EX110 routinely cross Earth’s orbit, Atens briefly cross and Amors cross Mars’ orbit but miss Earth’s. Credit: ESA
As 2014 EC is another Earth-approaching asteroid like 2014 EX110, there’s always a possibility it could smack out planet in the future. And I do mean future. At the moment, there’s a one in 2.7 million chance of an impact in 2025. Once more observations are in and the orbit refined, those chances will likely be even less.
Amateur astronomers living in Europe, the Middle East and Africa will be able to spot this little rock shining dimly at around magnitude 13.5-14.0 for a couple of hours centered on closest approach as its tears across the constellations Hydra, Antlia and Vela. You’ll need at least an 8-inch telescope to spot it. Click HERE to get positions to make a map of its travels.
For those of us without giant telescopes or living where it daytime during the close passage, the Virtual Telescope Project will feature a live webcast of 2014 EC’s flyby. Tune in around 1:30 p.m. CST. If that link isn’t working, please check SLOOH’s live-cast HERE.
Asteroid 2014 DX110 orbits in nearly the same plane as Earth’s orbit and will be passing 0.9 lunar distances (216,00 miles) from us around 3 p.m. today. Credit: Virtual Telescope Project
The space rocks just keep a comin’. This time, newly discovered 2014 DX110 will pass just 216,000 miles from the Earth today around 3 p.m. CST. Break out those stopwatches – this 98-foot-wide bugger will be speeding by at 32,076 mph.
Bear in mind that close flybys of Earth are fairly routine with an average of one or two asteroids a month passing within the moon’s distance of our planet. 2014 DX 110 is no exception and poses no harm to Earth. What makes the flyby of interest is the very thing that makes it so routine. We now see so many of these lively asteroidal sprites thanks to better equipment and multiple sky surveys. This one was captured by the Pan-STARRS1 survey from Maui, Hawaii on Feb. 28.
You can also watch the flyby on live webcast with commentary courtesy of the fine folks at the Virtual Telescope Project. The show starts at 3:30 p.m. CST (4:30 Eastern, 1:30 Pacific). If you miss it, the group plans another live Webcast when 2014 CU13 zips by on March 10. While that asteroid’s larger at 590 feet (180 meters), it will be considerably farther at 1.86 million miles.
Illustration showing asteroids orbiting the sun. Apollo asteroids like 2014 DX110 have orbits that take them from inside the asteroid belt at farthest to approximately Earth’s distance from the sun when closest. Credit: NASA/ JPL-Caltech
2014 DX110 belongs to the same class of near-Earth asteroids from whence came the mighty meteorite that exploded over Russia last February 15. These Earth-crossings bodies are named for asteroid 1862 Apollo, discovered in 1932. Apollos have orbits that take them very near the Earth with the potential for a future collision.
Don’t worry too much about DX110. According to NASA’s Earth Impact Risk Summary site, it has a 1 in 10,000,00 chance of hitting the planet on March 4, 2046. But since this estimate is based only on 28 observations spanning just under 4 days, future observations will probably lessen that barely significant probability even more.
Too bad a close approach won’t mean a bright point of light. The asteroid isn’t expected to get any brighter than magnitude 15, putting it well beyond the reach of beginners and even many amateurs. Why? It’s just too small. You’ll need at a 12.5-inch telescope and a darn good map to track it, since DX110 will be dashing across the sky.
Most likely you’ll be pouring another cup of coffee or trying not to yawn too loudly at a meeting when 2014 DX110 goes whizzing by later today. Or maybe you’ll get fired up and dial up a live view at the link above. Know this. Despite over 4.5 billion years of time to clean up its act, the solar system still has enough leftover rocks and snowballs to rattle the nerves. Just a little.
UPDATE March 5: Another just-discovered asteroid, 2014 EC, will pass considerably closer to Earth tomorrow at 3 p.m. – hey, how about that, same as today’s flyby. Predictions call for it to miss us by 48,000 miles. Again, there’s no threat of a strike. Asteroids can pass very close to the planet without concern about being “sucked in” by gravity because they’re moving forward in their orbits far too fast. The Virtual Telescope Project will also be featuring a live webcast of 2014 EC’s flyby.
(Note: The webcast link for 2014 EC is correct but I’ve noticed it doesn’t connect on occasion. I’ll update again if the link changes. You can also check out SLOOH’s live-cast HERE.)
Pictures of Pallas (right) taken by the Hubble Space Telescope and a model of its surface. The darker, circled area may be a large impact crater. Pallas is named for Pallas Athena, an alternate name for the Greek goddess Athena of wisdom and courage. Credit: NASA / JPL
Being number two isn’t all that bad. Less pressure than the number one spot and yet you still have a foot in the limelight. Asteroid 2 Pallas was the second asteroid discovered back in the days when asteroids were so few and novel they were called planets. German astronomer Heinrich Olbers accidentally ran across it while attempting to find another asteroid, Ceres, on March 28, 1802.
This week you can see Pallas at its brightest in two decades as it treks from Sextans into Hydra the Water Snake during convenient evening viewing hours. With the asteroid shining at around magnitude 7 – just one level fainter than naked eye visibility – all you need is a pair of binoculars, a map and a clear night.
The path of asteroid 2 Pallas as it slides along the back of the water snake constellation Hydra. It will appear as a star in telescopes and binoculars moving slowly to the north night by night. Stars shown to magnitude 8. Click for large version. Stellarium
At 338 miles across, Pallas bests Vesta in size by just 12 miles, making it the second largest asteroid after Ceres, the only main belt asteroid also classified as a dwarf planet. Unlike the planets, Pallas orbits the sun in a highly inclined orbit (34.8 degrees) taking 4.6 years to complete one spin around the sun. Pallas’ average distance from the sun is 257 million miles, but this month it’s lined up favorably with Earth and only about 115 million miles away. It was last this bright in 1991 and won’t be again until 2028.
Use this wide-field map to help you find Hydra and Alphard, its brightest star at 2nd magnitude. Alphard is roughly one “fist” held at arm’s length below and on either side of Procyon and Regulus. The map shows the sky facing south-southeast around 9 p.m. local time in early March. Stellarium
Being so much smaller than any of the eight planets, Pallas looks exactly like a star through most telescopes. Even the orbiting Hubble Space Telescope, located far above the blurring effects of Earth’s turbulent atmosphere, sees the asteroid as a pixelated object the shape of a flattened sphere with a large, darker “depression” that might be a crater.
The orbit of Pallas is rather wildly inclined, well outside the tilts of the other planets which lie in nearly the same plane. This view shows where Pallas is today March 3, 2014. Credit: NASA/JPL
Don’t expect a mission to the #2 anytime soon; Pallas’ highly tilted orbit makes it extremely difficult, energy and time-wise, to dispatch a probe for in-depth study and photo-taking.
Beautiful slice of the CR2 meteorite NWA 7837 from the Sahara Desert. Pallas’ surface shows similarities with this space rock. Credit: Sergey Vassiliev
That hasn’t stopped astronomers from eking out what they can across the millions of miles that separate us. Pallas receives light from the sun, absorbing some and reflecting the rest back into space. Rocks absorb light according to their internal makeup, imprinting their mineral signatures in the light they reflect back into space. Different rocks, different imprints.
Examining Pallas’ light with a spectrograph, which can dissect light like a doctor working a scalpel, we can identify basic minerals on the asteroid’s surface. From these observations, astronomers have learned that Pallas has much in common with the CR group of carbonaceous chondrite meteorites, both of which are very ancient and contain water and carbon.
This week Pallas will be near Alphard, an orange-tinted star and the brightest in Hydra, making it easy to find. It rides high in the southeastern sky around 9 p.m. local time. At magnitude 2 (Big Dipper brightness), Alphard stands out in a rather empty region of sky. You can find it by reaching your balled fist to Regulus in Leo and looking a little more than a fist below and to its right. Or you can do the same with Procyon in Canis Minor and look below and left.
Next, focus your binoculars on Alphard and use the map to stepping-stone your way to Pallas. The fun begins when you observe the asteroid for a second or third time and watch it move among the stars pulled by the gentle tug of the sun’s gravity.
Look toward the west this evening about half hour after sunset to see a beautiful 1 1/2 day old crescent moon. Stellarium
The crescent moon’s return to tonight’s sky is a guarantee, but the Chinese moon rover’s status remains uncertain. The Yutu rover began its third two-week long lunar night still crippled from a mechanical problem in late January when it attempted to store equipment in the box of the rover body in preparation for the previous night. Temperatures at the landing site can reach -292 F (-180 C). Bad news for sensitive electronics.
The Jade Rabbit rover, Yutu in Chinese, ventures across the lunar soil or regolith in this image made by the Chang’e 3 lander on Dec. 13, 2013. Credit: CNSA/China News
Photo of the Chang’e 3 lander taken by Yutu and tweeted by China’s Xinhua News Service Saturday Feb. 22, 2014 shortly before the onset of lunar night #3. The next lunar day for the mission begins March 10-11. Credit: CNSA/Xinhua News
“Mechanical issues remain unresolved,” according to Xinhua News. China’s State Administration of Science, Technology and Industry for National Defense (SASTIND), noted that Yutu only carried out fixed point observations during its third, two-week-long lunar day with its panorama camera, infrared imager and radar through at least Feb. 22. In other words, it appears to be functioning but not moving.
There’s much speculation that moon dust may have gummed up the works, but who knows. While Chinese officials have touted the successes of the moon missions, they’ve been very secretive about the status of the rover ever since the problems occurred.
Pity that the Chinese couldn’t be more open about the mission. If they only understood that we get it. Problems happen all the time on space missions. Remember the loss of the Mars Climate Orbiter in 1999 due to a mixup using English inches instead of metric? Embarrassing, yes, but the more information that’s shared, the more support the agency will receive, and the better chance problems will be resolved in future missions. Someone out there may even have a work-around to Yutu’s dilemma, but we may never know.
Comet NEOWISE discovered by the re-activated NEOWISE probe on Feb. 14, 2014. The telescope searches for asteroids and comets by examining the heat they give off as infrared light. Credit: NASA
Great bit of news. NASA’s recently re-awakened Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) rubbed the sleep from its eyes and promptly discovered a new comet. The Earth-orbiting telescope snagged C/2014 C3 (NEOWISE) on Valentine’s Day when it was about 143 million miles (230 million km) from Earth. Although the comet’s orbit isn’t precisely determined, it appears to originate from the realm of the distant planets Uranus and Neptune.
Originally called the Wide-field Infrared Survey Explorer (WISE), its primary mission wrapped up in 2011 after two very successful years. WISE performed an all-sky survey in infrared light (heat) that uncovered tens of thousands of new asteroids, luminous, star-burst galaxies and dim brown dwarfs. Along the way it also added 21 new comets to its booty.
Our eyes can’t see infrared, but we sense it as heat. The probe’s 15.7-inch (0.4-m) telescope is optimized for just that very slice of the spectrum. Infrared light penetrates dust clouds revealing what’s inside (newborn stars for instance) and can see otherwise faint, dark asteroids by the heat they radiate into space.
Two years later in September 2013 WISE was taken out of hibernation and re-activated as NEOWISE to assist NASA’s efforts to identify the population of potentially hazardous near-Earth objects. It will also study previously known asteroids and comets to better understand their sizes and compositions.
Comet Lovejoy on Feb. 28, 2014. Credit: Rolando Ligustri
Wondering what’s going on with comets you and I might see in our telescopes? Comet ISON has long gone to comet heaven. And three other bright comets – Lovejoy, Encke and C/2012 X1 LINEAR - that kept us from our sleep so many nights have either faded from view or lost their luster. Morning skywatchers using 6-inch or larger telescopes can still follow Lovejoy and X1 LINEAR, both glowing around magnitude 9, but it’s slim pickings otherwise.
Sit tight. Come late summer we’ll have several nice binocular comets from which to choose.
This scanning electron microscope image shows spheroidal features embedded in a layer of iddingsite, a mineral formed by action of water, in the Yamato 000593 meteorite. An area with the spheres, circled in red, was found to have about twice as much carbon present as an area (circled in blue) without the spheres. The measure at left is one micron (.001 mm) or about the size of some bacteria. Credit: NASA
A team of scientists at NASA’s Johnson Space Center in Houston and the Jet Propulsion Laboratory in Pasadena, Calif., has found evidence of past water movement and tiny carbon-rich spherules in Martian meteorite Yamato 000593.
The 30-pound (13.7 kg) chunk of Mars was collected on the Yamato Glacier in Antarctica by the Japanese Antarctic Research Expedition in 2000. It was once part of a 1.3 billion year old Martian lava flow but was ejected by a meteorite impact 12 million years ago and landed near the south pole some 50,000 years ago.
Scientists distinguish Mars rocks from Earth’s by the atmospheric gases trapped inside (these are compared to measurements of the planet’s atmosphere made in situ by our Mars landers) and the distinctive composition of oxygen in the minerals making up the rock. Martian rocks contain a greater proportion of oxygen’s heavier forms, called isotopes, compared to Earth rocks.
This scanning electron microscope image of a polished thin section of a meteorite from Mars shows tunnels and curved micro-tunnels deep within Yamato 000593. Iddingsite is a clay mineral indicating that water once flowed through cracks in the rock. The scale bar at lower left is 2 microns. Credit: NASA
The team made two fascinating discoveries when they peered closely into the interior of the meteorite:
* Micro-tunnel structures with curved, undulating shapes that thread their way through the rock and resemble similar textures reported by other researchers in terrestrial basaltic glasses created by bacteria.
* Distinct nanometer- to-micrometer-sized spherules resembling bacteria that are sandwiched between layers within the rock and enriched in carbon compared to their surroundings.
Similar bacteria-like structures are found inside the Martian Nakhla meteorite that fell in Egypt in 1911. Credit: NASA / ARES / JSC
Similar spherical features were previously seen in the Martian meteorite Nakhla that fell in Egypt in 1911. Everett Gibson, who led the new study, was also involved in the 1996 study of Allan Hills 84001, the first Martian meteorite thought to be touched by life’s imprint. I’ll never forget the excitement and controversy at the time when it was announced that possible evidence of life in the form of worm-like structures and organic molecules were found within the meteorite.
Bacteria-like structures in the Martian Allan Hills 84001 (ALH 84001) meteorite discovered in Antarctica in 1984. Credit: NASA
We know now that virtually all potential “signs of life” found by the 1996 researchers could have been created by chemical and other inorganic processes, making the team’s results inconclusive at best.
Likewise, Gibson and Lauren White, lead author of the recent paper on Yamato 000593 in the International Journal of Astrobiology, allow that non-living processes could have cooked up the carbon-rich structures and micro-tunnels. Still, the similarities between structures in basaltic Earth rocks and Yamato 000593 might also imply life’s handiwork on a planet other than our own.
Rock-eating bacteria – called endoliths – inside a basaltic rock found 3,900 feet (1,200 meters) beneath the Indian Ocean floor. Credit: NOAA Ocean Explorer
“As more Martian meteorites are discovered, continued research focusing on these samples collectively will offer deeper insight into attributes which are indigenous to ancient Mars,” said White. “As these meteorite studies are compared to present day robotic observations on Mars, the mysteries of the planet’s seemingly wetter past will be revealed.”
Knowing how scientists relish testing any new claim, especially one hypothesizing early life on Mars, the story of Yamato 000593 can’t help but be revised and expanded in the months and years ahead.