Cassini Exposes Phoebe As More Planet Than Moon

Color-composite image of Phoebe as seen by Cassini in 2009.

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Saturn’s curious moon Phoebe features a heavily-cratered shape and orbits the ringed planet backwards at a considerable distance of over 8 million miles (12.8 million km). According to recent news from the Cassini mission Phoebe may actually be a Kuiper Belt object, having more in common with planets than it does with any of Saturn’s other satellites.

132 miles (212 km) in diameter, Phoebe is the largest of Saturn’s irregular moons — a cloud of small, rocky worlds held in distant orbits at highly inclined paths. Its backwards (retrograde) motion around Saturn and dense composition are dead giveaways that it didn’t form in situ within the Saturnian system, but rather was captured at some point when it strayed too close to the gas giant.

In fact it’s now thought that Phoebe may be a remnant from the formation of the Solar System — a planetesimal — with its own unique history predating its adoption into Saturn’s extended family of moons.

“Unlike primitive bodies such as comets, Phoebe appears to have actively evolved for a time before it stalled out,” said Julie Castillo-Rogez, a planetary scientist at NASA’s Jet Propulsion Laboratory. “Objects like Phoebe are thought to have condensed very quickly. Hence, they represent building blocks of planets. They give scientists clues about what conditions were like around the time of the birth of planets and their moons.”

Although Phoebe is heavily eroded and irregularly-shaped today at one time it may have been much rounder. But an early composition of radioactive elements would have generated heat, and as it warmed it “deflated” through compression, growing denser and denser.

Map of Phoebe's surface. (NASA/JPL-Caltech/SSI/Cornel)

Now, Phoebe exhibits a similar density to Pluto — another denizen of the Kuiper Belt.

At some point Phoebe may even have had water, kept liquid by its radioactive heat. That is, until the heat faded and it froze, creating the icy surface detected by Cassini’s instruments.

Still, Cassini’s study of Saturn’s moons has provided scientists with clues to what was happening much earlier on in the Solar System. What caused Phoebe to drift inwards to be caught up in orbit around Saturn? How did it survive such a supposed shuffling of planets and other worlds did not? As Cassini continues its investigation answers — and undoubtedly even more questions — will be uncovered.

Read more on NASA’s news release here.

Image: NASA/JPL/SSI. Color composition by Gordan Ugarkovic.

Enterprise “GO” for Big Apple Fly Over on April 27 – NYC Viewing Guide

Space Shuttle Enterprise will Fly from DC to NYC on April 27. Enterprise is mounted atop NASA 747 Carrier Jet at Dulles Airport and all set for ferry flight and fly around of NYC before landing at JFK airport. Enterprise is bolted on top of the Shuttle Carrier Aircraft (SCA) and visible from the upper levels of a Daily Parking Garage at Dulles Airport. Credit: Ken Kremer

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Unless the weather changes drastically, Space Shuttle Enterprise will depart Dulles International Airport and the D.C. area on her final ferry flight for her history making Big Arrival at the Big Apple on Friday morning, April 27 and a spectacular fly around of the New York City Metro area and towering Skyscrapers.

NASA managers have given the “GO” for takeoff of Enterprise early Friday morning. Enterprise is primed and mounted atop NASA 905 – the specially modified Boeing 747 Shuttle Carriar Aircraft (SCA) that transports all the orbiters on cross country ferry trips; see my photo above.

In less than 24 hours, New York City will be the permanent new home to the Enterprise, NASA’s first shuttle vehicle.

From around 9:30 a.m. to 11:30 a.m., Enterprise atop the SCA will fly at quite low altitudes over various landmarks and historic locations in the New York City metropolitan area, putting on a dramatic sky show for millions of residents and visitors in the local New York and New Jersey region.

The mated duo is expected to make one or more mind bending, not-to-be-missed low passes over the iconic Statue of Liberty, her new home at the Intrepid Sea, Air & Space Museum Museum and other breathtaking locales throughout Manhattan, Brooklyn, Queens and New York’s waterways, before landing at John F. Kennedy (JFK) International Airport.

Space Shuttle Enterprise flew over New York City only once before of June 10, 1983 on a return flight from display at the Paris Air Show in France and a European tour of Germany, Italy and the UK. Richard Drew / AP

The public is invited to view the momentous Enterprise fly over atop the 747 from the flight deck of the Intrepid at Pier 86. The museum plans to open early.

Viewers can expect magnificent viewing opportunities inside New York City, from the ground level and up to the top of skyscrapers like the Empire State Building, as well as unparalleled Manhattan skyline views across the river from the New Jersey shoreline, stretching north and south along the Hudson River.

Depending on how far north the SCA flies, Enterprise might also be visible from nearby areas of Westchester and Rockland Counties and Connecticut.

The exact flyover route depends on weather and operational constraints and has not been released for security reasons.

The weather forecast is favorable with sunny and breezy conditions expected with temperatures around 50 degrees F. Winds gusts are the only potential hang up at this time. Dress warmly.

1500 VIP’s from New York will greet Enterprise after landing at JFK.

Enterprise will depart directly from Dulles for New York. Unlike the two hour long flyaround arrival of Space Shuttle Discovery to the D.C. area and Dulles on April 17, there will be no fly around of the DC area for this ferry flight of Enterprise.

Barely a week ago, Enterprise and Discovery swapped places at the Smithsonian’s Steven F. Udvar-Hazy Center outside Washington, D.C. following a nose to nose shuffle and meet up attended by a crowd of about 10,000 visitors.

Space Shuttle Enterprise and the SCA flew very briefly over New York City just once before in 1983 on a return trip from display at the Paris Air Show in France and an international tour of Germany, Italy, the UK and Canada.

You can catch beautiful view and photos of the takeoff of Enterprise from Dulles very easily from the upper levels of the Daily Parking garages. See my photo of Enterprise strapped to the SCA Jumbo Jet at Dulles herein and in this preview story.

Ken will be on hand for the history making Grand Entrance of the Enterprise over Manhattan’s skyline. Feel free to send me your Enterprise photos to post here at Universe Today.

Don’t miss this once-in-a-lifetime chance to see space history as a path finding NASA Space Shuttle – named after Star Trek’s Starship Enterprise – fly’s over the greatest city on Earth !

The Shuttle Enterprise rolled out in 1976 with the cast of Star Trek !
In 1976, NASA's space shuttle Enterprise rolled out of the Palmdale manufacturing facilities and was greeted by NASA officials and cast members from the 'Star Trek' television series. From left to right they are: NASA Administrator Dr. James D. Fletcher; DeForest Kelley, who portrayed Dr. "Bones" McCoy on the series; George Takei (Mr. Sulu); James Doohan (Chief Engineer Montgomery "Scotty" Scott); Nichelle Nichols (Lt. Uhura); Leonard Nimoy (Mr. Spock); series creator Gene Rodenberry; an unnamed NASA official; and, Walter Koenig (Ensign Pavel Chekov). Credit: NASA

How Small Are Atoms?

No fruits were harmed in the making of this video.

Here on Universe Today we often discuss things that exist on the atomic and sub-atmonic scale. Even though astronomy is concerned with very big things that happen over very, very large distances and time spans, the reality is that our Universe is driven by events occurring on the tiny atomic scale.

We all know atoms are really small (and the particles inside them are even smaller.) But… how small are they, really? To help answer that question, here’s a neat little animation from TEDEducation, presented by Jonathan Bergmann and Cognitive Media.

(That’s one big grapefruit!)

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Weird Swirly Features Found on Mars

Cooling lava on Mars can form patterns like snail shells when the lava is pulled in two directions at once. Such patterns, rare on Earth, have never before been seen on Mars. This image, with more than a dozen lava coils visible, shows an area in a volcanic region named Cerberus Palus that is about 500 meters (1640 feet) wide. Credit: NASA

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Strange coiling spiral patterns have been found on Mars surface by a graduate student who was doing what many of us enjoy: looking through the high-resolution images from the HiRISE camera on the Mars Reconnaissance Orbiter. Similar features have been seen on Earth, but this is the first time they have been identified on Mars. However, on Mars, these features, called lava coils, are supersized. “On Mars the largest lava coil is 30 meters across – that’s 100 feet,” said Andrew Ryan from Arizona State University. “That’s bigger than any known lava coils on Earth.”

The lava coils resemble snail or nautilus shells. Ryan has found about 269 of these lava coils just in one region on Mars, Cerberus Palus. 174 of them swirl in a clockwise-in orientation, 43 are counterclockwise, and 52 of the features remain unclassified due to resolution limits.

A small lava coil on pahoehoe flow, Kilauea Volcano, Hawai`i(see the pocket knife for scale.) Credit: W.W. Chadwick

On Earth, lava coils can be found on the Big Island of Hawaii, mainly on the surface of ropey pahoehoe lava flows. They usually form along slow-moving shear zones in a flow; for example, along the margins of a small channel, and the direction of the flow can be determined from a lava coil.

“The coils form on flows where there’s a shear stress – where flows move past each other at different speeds or in different directions,” said Ryan. “Pieces of rubbery and plastic lava crust can either be peeled away and physically coiled up – or wrinkles in the lava’s thin crust can be twisted around.”

Similarly, Ryan said scientists have documented the formation of rotated pieces of oceanic crust at mid-ocean ridge spreading centers.

Newer lava lying between two older plates of rough, hardened lava was still hot and plastic enough to form coils and spirals when the plates slid past one another. This image shows an area about 360 meters (1200 feet) wide in Cerberus Palus. Credit: NASA

But Ryan and the co-author on the paper, Phil Christiansen, Principal Investigator for the Thermal Emission Imaging Spectrometer on the Mars Odyssey spacecraft, are certain water has nothing to do with the formation of the lava coils on Mars.

“There are no known mechanisms to naturally produce spiral patterns in ice-rich environments on the scale and frequency observed in this area,” they wrote in their paper. “It is also unlikely that ice-rich patterned regolith, which takes decades to centuries to develop, could fracture and drift. The lava coils and drifting polygonal and platy-ridge lava crust described above are therefore most consistent with known volcanic analogs, rather than ice-related processes.”
These features are probably quite young, formed 1.5 to 200 million years ago in Mars’ late Amazonian period when the planet was volcanically active.

The team’s paper presented at the 2012 Lunar and Planetary Science Conference

We Really Hope ET is Out There, But There’s Not Enough Scientific Evidence, Researchers Say

This artist's illustration gives an impression of how common planets are around the stars in the Milky Way. Credit: NASA, ESA, and M. Kornmesser (ESO)

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For many of us who grew up listening to Carl Sagan, watching robotic spacecraft travel to other worlds, and indulging in science fiction books and movies, it’s a given: one day we’ll find life somewhere else in the solar system or Universe. But are we being too optimistic? Two researchers say that our hopes and expectations of finding ET might be based more on optimism than scientific evidence, and the recent discoveries of exoplanets that might be similar to Earth are probably getting everyone’s hopes up too high.

Astrophysicist Edwin Turner from Princeton and researcher David Spiegel from the Institute for Advanced Study say the idea that life has or could arise in an another Earth-like environment has only a small amount of supporting evidence, most of it extrapolated from what is known about abiogenesis, or the emergence of life, on early Earth. Their research says the expectations of life cropping up on exoplanets are largely based on the assumption that it would or will happen if the same conditions as Earth exist elsewhere.

Using a Bayesian analysis — which weighs how much of a scientific conclusion stems from actual data and how much comes from the prior assumptions of the scientist — the duo concluded that current knowledge about life on other planets suggests Earth might be a cosmic aberration, where life took shape unusually fast and furious. If so, then the chances of the average terrestrial planet hosting life would be low.

“Fossil evidence suggests that life began very early in Earth’s history and that has led people to determine that life might be quite common in the universe because it happened so quickly here, but the knowledge about life on Earth simply doesn’t reveal much about the actual probability of life on other planets,” Turner said.

So, if a scientist starts out assuming that the chances of life existing on another planet is as large as on Earth, then their scientific results will be presented in a way that supports that likelihood, Turner said.

“Information about that probability comes largely from the assumptions scientists have going in, and some of the most optimistic conclusions have been based almost entirely on those assumptions,” he said.

Therefore, with all the exoplanets being found, and as our discoveries have become more and more enticingly Earth-like, these planets have our knowledge of life on Earth projected onto them, the researchers said.

How does an exoplanet researcher feel about this? Turner and Spiegel found a sympathetic soul in Joshua Winn from the Massachusetts Institute of Technology, who said that the two cast convincing doubt on a prominent basis for expecting extraterrestrial life.

“There is a commonly heard argument that life must be common or else it would not have arisen so quickly after the surface of the Earth cooled,” Winn said. “This argument seems persuasive on its face, but Spiegel and Turner have shown it doesn’t stand up to a rigorous statistical examination — with a sample of only one life-bearing planet, one cannot even get a ballpark estimate of the abundance of life in the universe.

It is true that science is about facts — not about what your gut feelings are. But there’s a strong argument that we need inspiration to do the best, most engaging science. Writer Andrew Zimmerman Jones blogged today at PBS about how many scientists were spurred to follow their careers by reading science fiction when they were young.

“The finest science fiction is inspired by the same thing that has inspired the greatest science discoveries throughout the ages: optimism for the future,” wrote Jones.

And perhaps that is what is mostly behind our hopes for finding ET: optimism for the future of the human race, that we really could one day travel to other worlds, and find new friends — “to explore strange new worlds, to seek out new life and new civilizations, to boldly go where no one has gone before…”

Turner and Spiegel do say they are not making judgments, but just analyzing existing data that suggests the debate about the existence of life on other planets is framed largely by the prior assumptions of the participants.

“It could easily be that life came about on Earth one way, but came about on other planets in other ways, if it came about at all,” Turner said. “The best way to find out, of course, is to look. But I don’t think we’ll know by debating the process of how life came about on Earth.”

Read the team’s paper.

Sources: Princeton, PBS

Outer Space – Mind Blowing Video from Jupiter and Saturn

Video Caption: This mesmerizing video unveils incredibly amazing sequences around Jupiter and Saturn from NASA’s Cassini and Voyager missions set to stirring music by “The Cinematic Orchestra -That Home (Instrumental)”. Credit: Sander van den Berg

Don’t hesitate 1 moment ! Look and listen to this mind blowing video of the Jupiter and Saturnian systems.

If you love the wonders of the hitherto unknown Universe unveiled before your eyes – and long to explore – feast your eyes on this short new video right now titled simply; “Outer Space”. Continue reading “Outer Space – Mind Blowing Video from Jupiter and Saturn”

Meteorite Hunters Find Fragments from the Recent ‘Daytime Fireball’ in California

Meteorite expert and researcher Peter Jenniskens with a fragment of the bolide seen over California on April 22, 2012. Image via Franck Marchis' Cosmic Diary blog.

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Meteorite hunters have been successful in locating fragments from the huge meteor visible in the daytime skies over California last weekend. One of the successful hunters was Peter Jenniskens, an expert in meteors and meteorites, perhaps best known for retrieving the fragments of asteroid 2008 TC3 which fell in Sudan in 2008. Astronomer Franck Marchis wrote in his Cosmic Diary blog that Jenniskens realized the size of the California meteor was very similar to 2008 TC3, and so fragments should have reached the surface, just like they did in 2008.

Jenniskens went out searching and found a four-gram fragment of the meteor in a parking lot in Lotus, California.

Update: NASA and the SETI Institute are asking the public to submit any amateur photos or video footage of the meteor that illuminated the sky over the Sierra Nevada mountains and created sonic booms that were heard over a wide area at 7:51 a.m. PDT Sunday, April 22, 2012.


Marchis wrote that several scientists from the Bay Area met at NASA Ames Research Center on April 24 to discuss a strategy for a search campaign, examining a radar data map which showed that dozens of fragments from the 100g to 1 kg range may have reached the ground.

Jenniskens said the fragment he found was a Carbonaceous Chondrites from the CM group of meteorites, “a rare type of primitive meteorite rich in organic compounds,” he said.

“We are very interested in this rare find,” said Greg Schmidt, deputy director of the NASA Lunar Science Institute. “With the public’s help, this could lead to a better understanding of these fascinating objects.”

Several other fragments were found, the first one by noted meteorite hunter Robert Ward.

“Getting fresh fragments of meteoroids, called meteorites, is key for astronomers to understand the composition of those remnants of the formation of the solar system,” Marchis wrote. “Fresh fragments are unaltered by the Earth’s weather and erosion processes, so they are pristine samples which can be used to detect organic materials for instance.”

Photos and video footage would help the scientists to better analyze the trajectory of the meteor and learn about its orbit in space. This information will also help scientists to locate the places along the meteor path where fragments may have fallen to the ground.

People who have photos or video of the meteorite are asked to contact Jenniskens at [email protected].

Marchis noted that a storm is heading towards the region and rain could alter the remaining fragments. So if you live nearby, consider heading out to take a look. Here is the radar map:

Radar map by Marc Fries showing the possible location of fragments (green area) of the meteor between Auburn and Placerville.

Marchis also said that if anyone has access to security camera footage taken on April 22, 2012 in the area of the fireball sighting, it may be useful to check them to see if the fireball was visible. “Astronomers could use them to pin down the site of the fall, maximizing the hunt for fragments,” he said.

Read more at the Cosmic Diary.

Recent Fireball Seen in Brazil Was Actually Re-Entering Centaur Rocket

UPDATE: After hearing from several experts, this fireball was likely NOT a re-entering rocket body. Bob Christy from Zarya.info confirmed that the two videos were reportedly made around 20:00 – 21:00 UTC, and according to SpaceTrack, the Centaur re-entered about 19 hours earlier at 01:23 UTC. Additionally, the re-entry ground track did not cross Brazil at a correlating time. Dr. Marco Langbroek from SatTrackCam concurred there is no chance this was a Centaur rocket. “Looking at the videos, to me it looks like a very slow, grazing meteor.”

We recently posted a video of a huge meteor streaking over the skies of Brazil. It turns out this wasn’t your average, ordinary, everyday meteor. It was actually a Centaur rocket body re-entering Earth’s atmosphere, according to fellow NASA Solar System Ambassador Eddie Irizarry. “An amazing video that shows a fireball lasting more than 30 seconds captured the reentry of a Centaur rocket body that was launched on 1985,” said Irizarry in an email, reporting for the Sociedad de Astronomía del Caribe, the Puerto Rican Astronomy Society. “The object was seen from southeast Brazil by hundreds of people on April 20, 2012 and on the same date, Intelsat 5A12’s rocket body was about to reenter Earth’s atmosphere, passing exactly over the ground track from which some people were able to capture amazing images,” reported Irizarry.

There’s a second video below, as well as a map of the area the fireball was seen.

Thanks to Eddie for sharing his insight.

More information about the Solar System Ambassador program.

Antarctica’s Ice Being Eaten Away From Below

The 820-foot-wide crack in Antarctica's Pine Island Glacier, seen from DC-8 during Operation IceBridge (Credit: NASA/DMS)


Data collected from a NASA ice-watching satellite reveal that the vast ice shelves extending from the shores of  western Antarctica are being eaten away from underneath by ocean currents, which have been growing warmer even faster than the air above.

The animation above shows the circulation of ocean currents around the western Antarctic ice shelves. The shelf thickness is indicated by the color; red is thicker (greater than 550 meters), while blue is thinner (less than 200 meters).

Launched in January 2003, NASA’s ICESat (Ice, Cloud and land Elevation Satellite) studied the changing mass and thickness of Antarctica’s ice from its location in polar orbit. An international research team used over 4.5 million surface height measurements collected by ICESat’s GLAS (Geoscience Laser Altimeter System) instrument from Oct. 2005 to 2008. They concluded that 20 of the 54 shelves studied — nearly half — were losing thickness from underneath.

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Most of the melting ice shelves are located in west Antarctica, where the flow of inland glaciers to the sea has also been accelerating — an effect that can be compounded by thinning ice shelves which, when grounded to the offshore seabed, serve as dams to hold glaciers back.

Melting of ice by ocean currents can occur even when air temperature remains cold, maintaining a steady process of ice loss — and eventually increased sea level rise.

“We can lose an awful lot of ice to the sea without ever having summers warm enough to make the snow on top of the glaciers melt,” said Hamish Pritchard of the British Antarctic Survey in Cambridge and the study’s lead author . “The oceans can do all the work from below.”

The study also found that Antarctica’s winds are shifting in response to climate change.

“This has affected the strength and direction of ocean currents,” Pritchard said. “As a result warm water is funnelled beneath the floating ice. These studies and our new results suggest Antarctica’s glaciers are responding rapidly to a changing climate.”

ICESat completed operations in 2010 and was decommissioned in August of that year. Its successor ICESat-2 is anticipated to launch in 2016.

Read more on NASA’s news release here.

Animation credit: NASA/Goddard CGI Lab

Dawn Reveals More of Vesta’s Secrets

These composite images from the framing camera aboard NASA's Dawn spacecraft show three views of a terrain with ridges and grooves near Aquilia crater in the southern hemisphere of the giant asteroid Vesta. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

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Vesta is finally giving up its secrets, thanks to the Dawn spacecraft! The latest images sent back from Dawn are revealing new details about the giant asteroid, including its varied surface composition, sharp temperature changes and clues to its internal structure. Scientists say all the information garnered by Dawn will help us to better understand the early solar system and processes that dominated its formation.

“Dawn now enables us to study the variety of rock mixtures making up Vesta’s surface in great detail,” said Harald Hiesinger, a Dawn participating scientist at Münster University in Germany. “The images suggest an amazing variety of processes that paint Vesta’s surface.”

Images from Dawn’s framing camera and visible and infrared mapping spectrometer, taken 420 miles (680 kilometers) and 130 miles (210 kilometers) above the surface of the asteroid, show a variety of surface mineral and rock patterns. Coded false-color images help scientists better understand Vesta’s composition and enable them to identify material that was once molten below the asteroid’s surface.

Researchers also see breccias, which are rocks fused during impacts from space debris. Many of the materials seen by Dawn are composed of iron- and magnesium-rich minerals, which often are found in Earth’s volcanic rocks. Images also reveal smooth pond-like deposits, which might have formed as fine dust created during impacts settled into low regions.

These images of Tarpeia crater, near the south pole of the giant asteroid Vesta, were obtained by the visible and infrared mapping spectrometer on NASA’s Dawn spacecraft. Image credit: NASA/JPL-Caltech/UCLA/INAF

At the Tarpeia crater near the south pole of the asteroid, Dawn imagery revealed bands of minerals that appear as brilliant layers on the crater’s steep slopes. The exposed layering allows scientists to see farther back into the geological history of the giant asteroid.

The layers closer to the asteroid’s surface bear evidence of contamination from space rocks bombarding Vesta. Layers below preserve more of their original characteristics. Frequent landslides on the slopes of the craters also have revealed other hidden mineral patterns.

This colorized image from NASA’s Dawn mission shows temperature variations at Tarpeia crater, near the south pole of the giant asteroid Vesta. Image credit: NASA/JPL-Caltech/UCLA/INAF

“These results from Dawn suggest Vesta’s ‘skin’ is constantly renewing,” said Maria Cristina De Sanctis, lead of the visible and infrared mapping spectrometer team based at Italy’s National Institute for Astrophysics in Rome.

This set of images from NASA's Dawn mission shows topography of the southern hemisphere of the giant asteroid Vesta and a map of Vesta’s gravity variations that have been adjusted to account for Vesta’s shape. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Dawn has given scientists a near 3-D view into Vesta’s internal structure. By making ultra-sensitive measurements of the asteroid’s gravitational tug on the spacecraft, Dawn can detect unusual densities within its outer layers. Data now show an anomalous area near Vesta’s south pole, suggesting denser material from a lower layer of Vesta has been exposed by the impact that created a feature called the Rheasilvia basin. The lighter, younger layers coating other parts of Vesta’s surface have been blasted away in the basin.

Dawn obtained the highest-resolution surface temperature maps of any asteroid visited by a spacecraft. Data reveal temperatures can vary from as warm as minus 10 degrees Fahrenheit (minus 23 degrees Celsius) in the sunniest spots to as cold as minus 150 degrees Fahrenheit (minus 100 degrees Celsius) in the shadows. This is the lowest temperature measurable by Dawn’s visible and infrared mapping spectrometer. These findings show the surface responds quickly to illumination with no mitigating effect of an atmosphere.

“After more than nine months at Vesta, Dawn’s suite of instruments has enabled us to peel back the layers of mystery that have surrounded this giant asteroid since humankind first saw it as just a bright spot in the night sky,” said Carol Raymond, Dawn deputy principal investigator at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “We are closing in on the giant asteroid’s secrets.”

The latest findings were presented today at the European Geosciences Union meeting in Vienna, Austria.

Source: NASA