Posted on by Ken Kremer

Asteroid Vesta Floats in Space in High Resolution 3-D

Vesta’s Eastern Hemisphere Floats in Space in 3-D. This anaglyph shows the varied topography of Vesta’s eastern hemisphere from craters in the north, the equatorial troughs and the huge mountain at the Souh Pole. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

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The giant Asteroid Vesta literally floats in space in a new high resolution 3-D image of the battered bodies Eastern Hemisphere taken by NASA’s Dawn Asteroid Orbiter.

Haul out your red-cyan 3-D anaglyph glasses and lets go whirling around Vesta and sledding down mountains to greet the alien Snowman! The sights are fabulous !

The Dawn imaging group based at the German Aerospace Center (DLR), in Berlin, Germany and led by team member Ralf Jaumann has released a trio of new high resolution 3-D images that are the most vivid anaglyphs yet published by the international science team.

The lead anaglyph shows the highly varied topography of the Eastern Hemisphere of Vesta and was taken during the final approach phase as Dawn was about 5,200 kilometers (3,200 miles) away and preparing to achieve orbit in July 2011.

The heavily cratered northern region is at top and is only partially illuminated because of Vesta’s tilted angle to the Sun at that time of year. Younger craters are overlain onto many older and more degraded craters. The equatorial region is dominated by the mysterious troughs which encircle most of Vesta and may have formed as a result of a gargantuan gong, eons ago.

The southern hemisphere exhibits fewer craters than in the northern hemisphere. Look closely at the bottom left and you’ll see the huge central mountain complex of the Rheasilvia impact basin visibly protruding out from Vesta’s south polar region.

This next 3-D image shows a close-up of the South Pole Mountain at the center of the Rheasilvia Impact basin otherwise known as the “Mount Everest of Vesta”.

The Mount Everest of Vesta in 3-D
This anaglyph shows the central complex and huge mountain in Vesta’s Rheasilvia impact basin at the South Pole. Does water ice lurk beneath the South Pole ?
Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

The central complex is approximately 200 kilometers (120 miles) in diameter and is approximately 20 kilometers (12 miles) tall and is therefore about two and a half times taller than Earth’s Mount Everest!

Be sure to take a long look inside the deep craters and hummocky terrain surrounding “Mount Everest”.

A recent study concludes that, in theory, Vesta’s interior is cold enough for water ice to lurk beneath the North and South poles.

Finally lets gaze at the trio of craters that make up the “Snowman” in the 3-D image snapped in August 2011 as Dawn was orbiting at about 2,700 kilometers (1,700 miles) altitude. The three craters are named Minucia, Marcia and Calpurnia from top to bottom. Their diameters respectively are; 24 kilometers (15 miles), 53 kilometers (33 miles) and 63 kilometers (40 miles).

3-D image of Vesta’s “Snowman” craters
The three craters are named Minucia, Marcia and Calpurnia from top to bottom. They are 24 kilometers (15 miles), 53 kilometers (33 miles) and 63 kilometers (40 miles) in diameter, respectively. Image resolution is about 250 meters (820 feet) per pixel. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

It is likely that Marcia and Calpurnia formed from the impact of a binary asteroid and that Minucia formed in a later impact. The smooth region around the craters is the ejecta blanket.

Dawn Orbiting Vesta above the “Snowman” craters
This artist's concept shows NASA's Dawn spacecraft orbiting the giant asteroid Vesta above the Snowman craters. The depiction of Vesta is based on images obtained by Dawn's framing cameras. Dawn is an international collaboration of the US, Germany and Italy. Credit: NASA/JPL-Caltech

Vesta is the second most massive asteroid in the main Asteroid Belt between Mars and Jupiter. It is 330 miles (530 km) in diameter.

Dawn is the first spacecraft from Earth to visit Vesta. It achieved orbit in July 2011 for a year long mission. Dawn will fire up its ion propulsion thrusters in July 2012 to spiral out of orbit and sail to Ceres, the biggest asteroid of them all !

Vesta and Ceres are also considered to be protoplanets.

Posted on by Nancy Atkinson

2012 BX34: Behind the Scenes in the Discovery of a Near Earth Asteroid

The images in which asteroid 2012 BX34 was discovered. Images are from Jan. 25, 2012 10:30 UT. Credit: Alex Gibbs, Catalina Sky Survey/University of Arizona

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Several blockbuster movies, television shows and commercials have depicted the discovery of an asteroid heading towards Earth and usually, somehow, impending doom is averted. But how do the discoveries of Near Earth Objects really happen? Asteroid 2012 BX34 buzzed by Earth last week, and even though this small asteroid was never considered a threat to Earth, its discovery still piqued the interest of the public. It was discovered by Alex Gibbs, an astronomer and software engineer from the Catalina Sky Survey. Universe Today asked Gibbs to share his experiences of being an asteroid hunter and what it was like to find this latest NEO that made the Top-20 list of closest approaches to Earth.

The Catalina Sky Survey is a research program at the University of Arizona and is part of the Spaceguard Survey, a NASA project to discover and catalog Earth-approaching and Potentially Hazardous Asteroids (PHAs).

When astronomers look through telescopes, asteroids don’t look much different from stars – they are just points of light. But these points of light are moving; however they are moving slow enough that to detect the motion, astronomers take a series of images, usually four images spaced 10-12 minutes apart.

Then, the observers run specialized software to examine their images for any star-like objects that are moving from one image to the next. The software removes any candidates that correspond to known objects or main-belt asteroids.

Gibbs said the software has a low detection threshold to avoid missing anything, so the observer looks over what the software found and determines which are real. The remaining objects that the software determines could be interesting are then sent in to the Minor Planet Center (MPC) at the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, for the team or others to follow up.

The Catalina Sky Survey's Schmidt Telescope. Image courtesy Catalina Sky Survey

Gibbs said his discovery images of 2012 BX34 were taken at 10:30 UT (3:30 am in Tucson) on January 25, 2012. He was using a Schmidt telescope on Mount Bigelow. At the time, the object was 1.8 million km away, moving 1.15 degrees/day across the sky, and at 20th magnitude.

On the night of discovery, Gibbs said 2012 BX34 seemed just like most of the NEOs they find. But something unusual happened the following night.

“No one seemed to be able to find it,” Gibbs said via email. “That happens sometimes, but it should have been pretty easy for the observatories that were looking. When my colleague, Rik Hill, found a ‘new’ object nearby I was suspicious that it might be the same object. The object’s rapid increase in brightness and apparent motion had made it difficult to recognize as the same object.”

When Gibbs put the two observations together he could tell they were the same object. But more importantly, he also could tell the object was going to come fairly close to Earth.

“That’s when I emailed the MPC to point out that they were the same object,” Gibbs said.

Asteroid Passing in Front of Galaxies Before Passing Earth from Alex Gibbs on Vimeo.

Even though this is what Gibbs does for a living, certainly there must be a certain thrill (or butterflies in the stomach) when it is realized one of these NEOs is coming fairly close to Earth?

“We realized it was going to come pretty close, but wouldn’t impact,” Gibbs said. “I knew it was small enough that it would disintegrate if it did, so although I was excited, I was also a little disappointed that it wasn’t going to put on more of a show. But I definitely prefer this to it being TOO flashy!”

The software at the MPC also figured out this asteroid was coming close, and just like in the movies, astronomer Gareth Williams, associate director of the MPC, was aroused from his sleep in the middle of the night by a pager message. But, said Williams in an interview with the BBC, “when I saw the miss distance was going to be 10 Earth radii, I said ‘that’s too far for me to get up,’ so I rolled over and went back to sleep.”

“That explains why the emails I exchanged with him later on were so short,” Gibbs said.

Captures of asteroid 2012 BX34 moving through the field of background stars. Credit: Alex Gibbs/Catalina Sky Survey.

At its closest approach, on January 27 15:15 UT, 2012 BX34 was 59,600 km from the Earth’s surface, moving 729 deg/day, appearing at 14th magnitude, which is 250 times brighter than when Gibbs first saw it.

Gibbs said it is common for discoveries to be followed up by others astronomers, though it’s not a rigid practice.

“Whenever we find something moving in an ‘interesting’ way we send it to the Minor Planet Center, as do all the other surveys,” he said. “The MPC publishes the objects on their public NEO Confirmation Page. Various parties then follow the objects up, both pros and amateurs. Whether an object is deemed interesting or not is primarily determined by software that looks at the motion and brightness, though we can often tell when we see it. We also submit anything that appears to have cometary features.”

As of January 29, 2012, 8,648 Near-Earth objects have been discovered, with about 840 of these NEOs being asteroids with a diameter of approximately 1 kilometer or larger. Also, 1,284 of these NEOs have been classified as PHAs.

“NEOs are ones that come within 1.3 AU of the Sun (since the Earth is at 1 AU it means they pass through our neighborhood),” Gibbs said. “ PHAs are those that are larger than about 150 m (500 ft) and come within 0.05 AU of Earth’s orbit, so that at some point in the future they may cross paths.” (See more info on PHAs here)

“The large asteroids are much brighter than objects like 2012 BX34,” Gibbs said. “We see them as they orbit the Sun, and can determine if they are likely to come close to the Earth at some point. That gives us a lot more time to do something about an impact from the most dangerous asteroids. However, we ought to be doing more to catalog all the asteroids that could potentially take out a city or cause a tsunami. We are finding them now, but not fast enough. An asteroid impact is one of the few predictable and potentially preventable natural disasters.”

Even though asteroid 2012 BX34 was one of the top-20 closest approaches by an asteroid, its size made it a non-issue. While bus-sized sounds pretty big, this is small enough that it would break apart and burn up in the atmosphere. Instead, it passed by harmlessly.

“But a close fly-by like this one serves to remind people that asteroids of all sizes do come by the Earth,” said Gibbs. “We need to be vigilant.”

As for Gibbs, he is back at his job of asteroid hunting, and tonight will be scanning the skies from a larger telescope on Mt. Lemmon in Arizona.

More info:
Catalina Sky Survey
The telescopes and facilities of the CSS
Minor Planet Center
Asteroid and Comet Impact Hazards website from NASA
NASA’s Near Earth Object Program

Posted on by Paul Scott Anderson

Hayabusa 2 Mission Approved by Japanese Government

Artist's conception of Hayabua 2 approaching the asteroid 1999 JU3. Credit: Akihiro Ikeshita/JAXA

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In 2010, the Japanese spacecraft Hayabusa completed an exciting although nail-biting mission to the asteroid Itokawa, successfully returning samples to Earth after first reaching the asteroid in 2005; the mission almost failed, with the spacecraft plagued by technical problems. The canister containing the microscopic rock samples made a soft landing in Australia, the first time that samples from an asteroid had been brought back to Earth for study.

Now, the Japanese government has approved a follow-up mission, Hayabusa 2. This time the probe is scheduled to be launched in 2014 and rendezvous with the asteroid known as 1999 JU3 in mid-2018. Samples would again be taken and returned to Earth in late 2020.

1999 JU3 is approximately 914 metres (3,000 feet) in diameter, a little larger than Itokawa, and is roughly spherical in shape, whereas Itokawa was much more oblong.

As is common for any space agency, the Japanese Aerospace Exploration Agency (JAXA) is working with tight budgets and deadlines to make this next mission happen. There is a possibility of a back-up launch window in 2015, but if that deadline is also not met, the mission will have to wait another decade to launch.

The asteroid Itokawa, visited by Hayabusa in 2005. Credit: JAXA

One of the main problems with Hayabusa was the failure of the sampling mechanism during the “landing” (actually more of a brief contact with the surface with the sample capturing device) to retrieve the samples for delivery back to Earth. Only a small amount of material made it into the sample capsule, but which was fortunate and ultimately made the mission a limited success. The microscopic grains were confirmed to have primarily come from Itokawa itself and are still being studied today.

To avoid a repetition of the glitches experienced by Hayabusa, some fundamental changes needed to be made.

This next spacecraft will use an updated ion propulsion engine, the same propulsion system used by Hayabusa, as well as improved guidance and navigation systems, new antennas and a new altitude control system.

For Hayabusa 2’s sample-collecting activities, a slowly descending impactor will be used, detonating upon contact with the surface, instead of the high-speed projectile used by Hayabusa. Perhaps not quite as dramatic, but hopefully more likely to succeed. Like its predecessor, the main objective of the mission is to collect as much surface material as possible for delivery back home.

Hopefully Hayabusa 2 will not be hampered by the same problems as Hayabusa; if JAXA can achieve this, it will be exciting to have samples returned from a second asteroid as well, which can only help to further our understanding of the history and formation of the solar system, and by extrapolation, even other solar systems as well.

Posted on by Jason Major

Help Astronomers Measure the Solar System!

The orbit of asteroid 433 Eros brings it close to Earth on Jan. 31. (www.astronomerswithoutborders.org)

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As the bright Mars-crossing asteroid 433 Eros makes its closest approach to Earth since 1975, astronomers around the globe are taking the opportunity to measure its position in the sky, thereby fine-tuning our working knowledge of distances in the solar system. Using the optical principle of parallax, whereby different viewpoints of the same object show slightly shifted positions relative to background objects, skywatchers in different parts of the world can observe Eros over the next few nights and share their images online.

The endeavor is called the Eros Parallax Project, and you can participate too!

433 Eros' path from jan. 30 - Feb. 1, 2012. (transitofvenus.nl)

Discovered in 1898, Eros was the largest near-Earth asteroid yet identified. Its close and relatively bright oppositions were calculated by astronomers of the day and used, along with solar transits by Venus (one of which, if you haven’t heard, will also occur this year on June 5!) to calculate distances in the inner solar system.

Having both events take place within the same year offers today’s astronomers an unparalleled opportunity to obtain observational measurements.

Through the efforts of the Astronomers Without Borders organization, along with Steven van Roode and Michael Richmond from the Transit of Venus project, anyone with moderate astrophotography experience can participate in the observation of Eros and share their photos via free online software.

Using the data gathered by individual participants positioned around the world, each with their own specific viewpoints, astronomers will be able to precisely measure the distance to Eros.

The more accurately that distance is known, the more accurately the distance from Earth to the Sun can be calculated – via the orbital mechanics of Kepler’s third law.

The tumbling motion of elongated 33-km-long Eros creates a changing brightness. (via transitofvenus.nl)

The last time such a bright pass of Eros occurred was in January of 1931. Observations of the asteroid made at that time allowed astronomers to calculate a solar parallax of 8″ .790, the most accurate up to that time and the most accurate until 1968, when data acquired by radar measurements gave more detailed measurements.

In many ways the 2012 close approach by Eros – astronomically close, but still a very safe 16.6 million miles (26.7 million km) away – will allow for a re-eneactment of the 1931 event… with the exception that this time amateur skywatchers will also contribute data, instantly, from all over the world!

One has to wonder…when Eros comes this close again in 2056, what sort of technology will we use to watch it then…

Find out more about the Eros Parallax Project and how to participate here.

And be sure to check out the article about the project on Astronomers Without Borders as well.

Posted on by Jason Major

Asteroid To Make Closest Approach Since 1975

Asteroid 433 Eros, seen by NASA's NEAR spacecraft on Feb. 29, 2000. (NASA/JPL/JHUAPL)

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On Tuesday, January 31, asteroid 433 Eros will come closer to Earth than it has in 37 years, traveling across the night sky in the constellations Leo, Sextans and Hydra. At its closest pass of 16.6 million miles (26.7 million km) the relatively bright 21-mile (34-km) -wide asteroid will be visible with even modest backyard telescopes, approaching magnitude 8, possibly even 7. It hasn’t come this close since 1975, and won’t do so again until 2056!

433 Eros is an S-type asteroid, signifying a composition of magnesium silicates and iron. S-types make up about 17 percent of known asteroids and are some of the brightest, with albedos (reflectivity) in the range of 0.10 – 0.22. S-type asteroids are most common in the inner asteroid belt and, as in the case of Eros, can even pass within the orbit of Mars.

Occasionally Eros’ orbit brings it close enough to Earth that it can be spotted with amateur telescopes. 2012 will be one of those times.

Eros was discovered on August 13, 1898, by astronomers Carl Gustav Witt in Berlin and Auguste Charlois in Nice. When Eros’ orbit was calculated it was seen to be an elongated oval that brought it within the orbit of Mars. This allowed for good observations of the bright asteroid, and eventually led to more accurate estimates of the distance from Earth to the Sun.

In February 2000 NASA’s NEAR Shoemaker spacecraft approached Eros, established orbit and made a soft landing on its surface, the first mission ever to do so. While in orbit NEAR took over 160,000 images of Eros’ surface, identifying over 100,000 craters, a million house-sized boulders (give or take a few) and helped researchers conclude that the cashew-shaped Eros is a solid object rather than a “rubble pile” held together by gravity.

View NEAR images of Eros’ surface.

Studying pristine objects like Eros gives insight into the earliest days of our solar system, and also allows scientists to better understand asteroid compositions… which is invaluable information when deciding how best to avoid any potential future impacts.

Orbit of 433 Eros for Jan. 31, 2012

Although Eros will be making a “close” approach to Earth on Jan. 31/Feb. 1, there is no danger of a collision. It will still remain at a very respectable distance of about 16.6 million miles (26.7 million km), or 0.178 AU. This is over 80 times the distance of the much smaller 2005 YU55, which safely passed within a lunar orbit radius on November 8, 2011.

If you do want to try viewing 433 Eros as it passes, you can find a diagram charting its path from Sky and Telescope here. According to the Sydney Observatory’s website “the coordinates on 31 January (from the BAA 2012 Handbook) are 10 hours 33 minutes 19.0 seconds RA and -4° 48’ 23” declination. On 10 February the RA is 10 hours 20 minutes 27.6 seconds and the declination is -14° 38’ 49 seconds.”

Also there’s an updated chart on Heavens Above showing Eros’ current position.

Eros should remain visible up until Feb. 10.

Thanks to Skyscrapers, Inc., for a report on 433 Eros by Glenn Chaple. Skyscrapers, Inc. is an amateur astronomy society in Rhode Island that operates the Seagrave Observatory, whose centerpiece is a beautiful 8 1/4″ Alvan Clark telescope built in 1878. I saw Halley’s Comet through that telescope in 1986 and have been hooked on astronomy ever since.

Posted on by Nancy Atkinson

Astronomers Capture Images of Asteroid 2012 BX34’s Close Flyby of Earth

Animation of asteroid 2012 BX34's flyby of Earth on January 27, 2012, at 11:04 UTC, using the GRAS telescope in New Mexico, USA. E. Credit: Guido, G. Sostero & N. Howes

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Small asteroid 2012 BX34 skimmed past Earth today, January 27, 2012, with closest approach at about 15:25 UT, and it passed only about 59,044 km (36,750 miles) or about ~0.2 lunar distance (or 0.0004 AU) above the Earth’s surface. It was discovered just a few days ago by the Catalina Sky Survey in Arizona.

Above is an animation created by image from Ernesto Guido, Giovanni Sostero & Nick Howes from the Remanzacco Observatory in Italy. However, they took this series of images remotely from the iTelescope (formerly called GRAS), near Mayhill, New Mexico, using a 0.10-m f/5 reflector + CCD.

“According to its absolute magnitude (H=27.6) this asteroid has an estimated diameter of roughly 8-18 meters, so it is very small,” the team said on their website. “At the moment of our images from New Mexico on January 27, 11:04UT, 2012 BX34 was moving at about ~318.86 “/min and its magnitude was ~15. At the moment of its close approach around 15UT of today, 2012 BX34 will be bright as magnitude ~13.8 and moving at ~1810 “/min.”

Below is a single 120-seconds exposure showing the object as a ~11-arcminutes trail (due to its fast speed). Also below is a video from Peter Lake using his telescope in New Mexico remotely from Melbourne Australia, who took a series of 11 images just 6 hours before its closest approach.

Single image of 2012 BX34's flyby of Earth on January 27, 2012, at 11:04 UTC, using the iTelescope telescope in New Mexico, USA. E. Credit: Guido, G. Sostero & N. Howes.

See this link to see an image taken by legendary comet and asteroid hunter Rob McNaught, using a telescope in Sliding Spring, Australia. McNaught’s data was used by the Goldstone Deep Space Communications Complex to obtain radar imagery to determine BX34’s shape, size and orbital parameters. At this point, there are various estimates of the asteroid’s size, which will be refined from all the data gathered by the various telescopes. But astronomers from JPL’s Asteroid Watch said the space rock was small enough that it wouldn’t have survived a trip through Earth’s atmosphere if it had been on a collision course with our planet.

The team from the Remanzacco Observatory have a great table on their website, the the top 20 closest approaches by NEOs (Near-Earth Objects) sorted by nominal distance. The table was computed on the NASA/Neo-JPL website.

Thanks to all the astronomers for sharing their images with Universe Today. We’ll add more as they become available.

Posted on by Ken Kremer

Does Water Ice Lurk Beneath the Poles of Vesta ?

Viewing the South Pole of Vesta and Rhea Silvia Impact Basin. This image obtained by Dawn’s framing camera shows the south pole of the giant asteroid Vesta and the circular Rheasilvia impact basin which scientists believe originated by a collision with another asteroid early in the asteroid's history. The image was recorded from a distance of about 1,700 miles (2,700 kilometers). The image resolution is about 260 meters per pixel. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

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The mysterious asteroid Vesta may well have more surprises in store. Despite past observations that Vesta would be nearly bone dry, newly published research indicates that about half of the giant asteroid is sufficiently cold and dark enough that water ice could theoretically exist below the battered surface.

Scientists working at NASA’s Goddard Space Flight Center in Greenbelt, Md., and the University of Maryland have derived the first models of Vesta’s average global temperatures and illumination by the Sun based on data obtained from the Hubble Space Telescope.

“Near the north and south poles, the conditions appear to be favorable for water ice to exist beneath the surface,” says Timothy Stubbs of NASA’s Goddard Space Flight Center in Greenbelt, Md., and the University of Maryland, Baltimore County. The research by Timothy Stubbs and Yongli Wang, of the Goddard Planetary Heliophysics Institute at the University of Maryland, was published in the January 2012 issue of the journal Icarus.

If any water lurks beneath Vesta, it would most likely exist at least 10 feet (3 meters) below the North and South poles because the models predict that the poles are the coldest regions on the giant asteroid and the equatorial regions are too warm.

Global Map of Average Surface Temperature of Vesta
This global map of average surface temperature shows the warmer equatorial zone of the giant asteroid Vesta is likely too warm to sustain water ice below the surface. But roughly half of Vesta is so cold and receives so little sunlight on average that water ice could have survived there for billions of years. The dividing lines (solid gray) are found at about 27 degrees north latitude and 27 degrees south latitude. This map, with temperatures given in kelvins, comes from the first published models of the average global temperature and illumination conditions on Vesta. Credit: NASA/GSFC/UMBC

If proven, the existence of water ice at Vesta would have vast implications for the formation and evolution of the tiny body and upend current theories.

The surface of Vesta is not cold enough for ice to survive all the time because unlike the Moon, it probably does not have any significant permanently shadowed craters where water ice could stay frozen on the surface indefinitely.

Even the huge 300 mile diameter (480-kilometer) crater at the South Pole is not a good candidate for water ice because Vesta is tilted 27 degrees on its axis, a bit more than Earth’s tilt of 23 degrees.

By contrast, the Moon is only tilted 1.5 degrees and possesses many permanently shadowed craters. NASA’s LCROSS impact mission proved that water ice exists inside permanently shadowed lunar craters.

New modeling shows that, under present conditions, Vesta's polar regions are cold enough (less than about 145 kelvins) to sustain water ice for billions of years, as this map of average surface temperature around the asteroid's south pole indicates.

The models predict that the average annual temperature around Vesta’s poles is below minus 200 degrees Fahrenheit (145 kelvins). Water ice is not stable above that temperature in the top 10 feet of Vestan soil, or regolith.

At the equator and in a band stretching to about 27 degrees north and south in latitude, the average annual temperature is about minus 190 degrees Fahrenheit (145 kelvins), which is too high for the ice to survive.

“On average, it’s colder at Vesta’s poles than near its equator, so in that sense, they are good places to sustain water ice,” says Stubbs in a NASA statement. “But they also see sunlight for long periods of time during the summer seasons, which isn’t so good for sustaining ice. So if water ice exists in those regions, it may be buried beneath a relatively deep layer of dry regolith.”

Vesta is the second most massive asteroid in the main Asteroid belt between Mars and Jupiter.

NASA’s Dawn Asteroid Orbiter is the very first mission to Vesta and achieved orbit in July 2011 for a 1 year long mission.

Dawn is currently circling Vesta at its lowest planned orbit. The three science instruments are snapping pictures and the spectrometers are collecting data on the elemental and mineralogical composition of Vesta.

The onboard GRaND spectrometer in particular could shed light on the question of whether water ice exists at Vesta.

So far no water has been detected, but the best data is yet to come.

In July 2012, Dawn fires up its ion thrusters and spirals out of orbit to begin the journey to Ceres, the largest asteroid of them all.

Ceres is believed to harbor huge caches of water, either as ice or in the form of oceans and is a potential habitat for life.

Posted on by Jason Major

Asteroid’s Unusual Light and Dark Crater

A 5-km-wide crater on Vesta displays light and dark material.

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Light and dark material spreads outward from a 5-km-wide crater on Vesta in this image from NASA’s Dawn spacecraft, acquired on October 22, 2011. While craters with differently-toned materials have been previously seen on the asteroid, it is unusual to find one with such a large amount of ejecta of different albedos.

This is a crop of a larger version which was released today on the Dawn website.

This brightness image was taken through the clear filter of Dawn’s framing camera. The distance to the surface of Vesta is 700 kilometers (435 miles) and the image has a resolution of about 70 meters (230 feet) per pixel.

Orbit map: Where is Dawn now?

Vesta resides in the main asteroid belt between the orbits of Mars and Jupiter and is thought to be the source of many of the meteorites that fall to Earth. The Dawn spacecraft successfully entered orbit around Vesta on July 16, 2011.

After its investigation of Vesta, Dawn will leave orbit and move on to Ceres. It will become the first spacecraft to orbit two different worlds.

Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Posted on by Nancy Atkinson

8-Meter-Wide Asteroid Will Pass Close to Earth January 27

Orbital parameters of Asteroid 2012 BX34 from JPL's Small Body Database.

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A small asteroid will pass extremely close to Earth tomorrow (January 27, 2012). Named 2012 BX34, this 11 meter- (36 feet-) wide 8 meter- (26-foot-) space rock (astronomers have updated their estimates of the size) will skim Earth less than 60,000 km (37,000 miles, .0004 AU)>, at around 15:30 UTC, (10:30 am EST) according to the Minor Planet Center. The latest estimates have this small bus-sized asteroid it traveling at about about 8,900 meters/second (about 20,000 miles per hour). 2012 BX34 has been observed by the Catalina Sky Survey and the Mt. Lemmon Survey in Arizona, and the Magdalena Ridge Observatory in New Mexico, so its orbit is well defined and there is no risk of impact to Earth.

Via the @AsteroidWatch Twitter feed, scientists from JPL said “It wouldn’t get through our atmosphere intact even if it dared to try.”

Amateur astronomers in the right place and time could view this object, as it should be about magnitude 14 at the time of closest approach. Click here to see a current orbit diagram, and here to view the ephemeris data. Nick Howes, with the Faulkes Telescope Project said his team is hoping to observe and image the asteroid, — although they aren’t sure if they will be able — but we hope to share their images later.

Update: see images from astronomers on our latest article regarding 2012 BX34

Hat Tip: Nick Howes

Posted on by Jason Major

Does Earth Have Many Tiny Moons?

This radar image of asteroid 2005 YU55 was obtained on Nov. 7, 2011. Credit: NASA/JPL/Caltech.

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Look up in a clear night sky. How many moons do you see? Chances are, you’re only going to count to one. Admittedly, if you count any higher and you’re not alone, you may get some funny looks cast in your direction. But even though you may not be able to actually see them, there may very well be more moons out there orbiting our planet.

For the time being, anyway.

Today, Earth has one major moon in orbit around it. (Technically the Earth-Moon system orbits around a common center of gravity, called the barycenter, but that’s splitting hairs for the purpose of this story.) At one time Earth may have had two large moons until the smaller eventually collided into the larger, creating the rugged lump we now call the farside highlands. But, that was 4 billion years ago and again not what’s being referred to here.

Right now, at his moment, Earth may very well have more than the one moon we see in the night sky. Surprise.

Of course, it would be a very small moon. Perhaps no more than a meter across. But a moon nonetheless. And there could even be others – many others – much smaller than that. Little bits of solar system leftovers, orbiting our planet even farther out than the Moon we all know and love, coming and going in short-lived flings with Earth without anyone even knowing.

This is what has been suggested by researcher Mikael Granvik of the University of Helsinki in Finland. He and his colleagues have created computer simulations of asteroids believed to be occupying the inner solar system, and what the chances are that any number of them could be captured into Earth orbit at any given time.

Orbit of 2006 RH120, a confirmed TCO identified in 2006.

The team’s results, posted Dec. 20 in the science journal Icarus, claim it’s very likely that small asteroids would be temporarily captured into orbit (becoming TCOs, or temporarily captured objects) on a regular basis, each spending about nine months in up to three revolutions around Earth before heading off again.

Some objects, though, might hang around even longer… in the team’s simulations one TCO remained in orbit for 900 years.

“There are lots of asteroids in the solar system, so chances for the Earth to capture one at any time is, in a sense, not surprising,” said co-author Jeremie Vauballion, an astronomer at the Paris Observatory.

In fact, the team suspects that there’s most likely a TCO out there right now, perhaps a meter or so wide, orbiting between 5 and 10 times the distance between Earth and the Moon. And there could be a thousand smaller ones as well, up to 10 centimeters wide.

So if these moons are indeed out there, why don’t we know about them?

Put simply, they are too small, too far, and too dark.

At that distance an object the size of a writing desk is virtually undetectable with the instruments we have now.. especially if we don’t even know exactly where to look. But in the future the Large Synoptic Survey Telescope (LSST) may, once completed, be able to spot these tiny satellites with its 3200-megapixel camera.

Once spotted, TCOs could become targets of exploration. After all, they are asteroids that have come to us, which would make investigation all the easier – not to mention cheaper – much more so than traveling to and back from the main asteroid belt.

“The price of the mission would actually be pretty small,” Granvik said. And that, of course, makes the chances of such a mission getting approved all the better.

Read more on David Shiga’s article on New Scientist here.

The team’s published paper can be found here.