What an asteroid hitting the Earth might look like. Image credit: NASA/Don Davis.
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Scientists aren’t entirely sure when the last major asteroid hit the Earth, but it’s certain to happen again. Alan Harris, asteroid researcher at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR), is hoping to head the next one off. Last month, Harris established an international collaboration of 13 researchers to investigate methods of shielding the Earth from near Earth objects (NEOs). The project is, appropriately, called NEOShield.
Asteroids approaching the planet typically travel between 5 and 30 kilometres (about 5 to 19 miles) per second. As that speed, a moderate sized body can have major consequences. The Barringer Crater in Arizona, often referred to as Meteor Crater, is a 1,200 metre crater (about 3,950 feet or 0.7 miles) that scientists hypothesize was caused by a 50 metre (164 feet) meteor.
The bad news is that there are thousands of known NEOs just like the one that made Meteor Crater, leading experts to posit that a dangerous collision could occur as often as every two hundred years.
Meteor Crater near Winslow, Arizona. Image credit: NASA.
The good news is that it’s possible to stop an asteroid hitting the Earth. You just have to be in the right place at the right time to give the object the right push in another direction.
Scientists are focusing on possible methods of redirecting threatening asteroids so they miss the Earth. “In order to modify their orbit and prevent a collision with Earth, a force must be exerted on them,” explains Alan Harris. “And at the precise time, as well.” One way to do this is to have a spacecraft impact a threatening asteroid, imparting enough force to change its orbit. “In my opinion, this is a very practical method,” said Harris. But there are still questions to answer, like how to guide the spacecraft to a moving target at the right angle for the right impact and how to minimize the effects of fuel movement on the spacecraft’s path.
Another way is to use the spacecraft’s gravitational pull to nudge the asteroid into a different orbit. If the object is far enough away, a tiny tug could have a big effect. But so far, “this method only exists on paper,” said Harris, “but it could work.”
An asteroid, docile in space but deadly to Earth. Image credit: NASA/JPL
Another third, less appealing prospect, is to use explosive power to break up an Earth-bound asteroid. But this could be disastrous, creating a shower of debris instead of one solid piece. As such, Harris considers this method a last resort. “If a very large, dangerous object with a diameter of one kilometre [0.6 miles] or more is discovered,” explains Harris, changing its orbit won’t be a option. “The greatest force we would be able to use to divert the asteroid from its path would be a nuclear explosion. This technique is regarded as a very controversial.”
Over the next three years, during which the European Union will support the project with four million Euros and international partners will contribute an additional 1.8 million Euros, the NEOShield project will research these defence methods. The scientists will focus on data from asteroid observations and lab experiments to generate computer simulations, ultimately determining how best to protect the Earth from future devastating impacts.
Mysterious X-ray flares caught by Chandra may be asteroids falling into the Milky Way's giant black hole. Credit: X-ray: NASA/CXC/MIT/F. Baganoff et al.; Illustrations: NASA/CXC/M.Weiss
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For the past several years, the Chandra telescope has detected X-ray flares occurring about once a day from the supermassive black hole at the center of the Milky Way Galaxy. These flares last a few hours with brightness ranging from a few times to nearly one hundred times that of the black hole’s regular output. What could be causing these unusual, mysterious flares? Scientists have determined that the black hole could be feasting hungrily on asteroids that come too close and vaporizing them, creating the flares. Basically, the black hole is eating asteroids and then belching out X-ray gas.
If confirmed, this result would mean that there is a huge, bustling cloud around the black hole containing hundreds of trillions of asteroids and comets.
“People have had doubts about whether asteroids could form at all in the harsh environment near a supermassive black hole,” said Kastytis Zubovas of the University of Leicester in the United Kingdom, and lead author of a new paper. “It’s exciting because our study suggests that a huge number of them are needed to produce these flares.”
The scientists say this really isn’t as far-fetched as it may sound, as it mirrors an event that regularly takes place in our Solar System: About every three days a comet is destroyed when it flies into the hot atmosphere of the Sun. Despite the significant differences in the two environments, the destruction rate of comets and asteroids by the Sun and the black hole at the center of our galaxy, called Sagittarius A*, or “Sgr A*” for short, may be similar.
These asteroids and comets have likely been ripped from their parent stars, and to create the flare the asteroids or comets have to be fairly large, at least 19 km (12 miles) wide.
The astronomers propose this scenario: An asteroid undergoes a close encounter with another object, such as a star or planet, and is thrown into an orbit headed towards Sgr A*. If the asteroid passes within about 100 million miles of the black hole, roughly the distance between the Earth and the Sun, it would be torn into pieces by the tidal forces from the black hole. These fragments then would be vaporized by friction as they pass through the hot, thin gas flowing onto Sgr A*, similar to a meteor heating up and glowing as it falls through Earth’s atmosphere. A flare is produced and the remains of the asteroid are swallowed eventually by the black hole.
“An asteroid’s orbit can change if it ventures too close to a star or planet near Sgr A*,” said co-author Sergei Nayakshin, also of the University of Leicester. “If it’s thrown toward the black hole, it’s doomed.”
The team says these results reasonably agree with models estimating of how many asteroids are likely to be in this region, assuming that the number around stars near Earth is similar to the number surrounding stars near the center of the Milky Way.
“As a reality check, we worked out that a few trillion asteroids should have been removed by the black hole over the 10-billion-year lifetime of the galaxy,” said co-author Sera Markoff of the University of Amsterdam in the Netherlands. “Only a small fraction of the total would have been consumed, so the supply of asteroids would hardly be depleted.”
This scenario would not be limited to asteroids and comets, however. Planets thrown into orbits too close to Sgr A* also could also be disrupted by tidal forces, although planets in the region are less common. And of course, if a planet was consumed, it would create an even larger flare; and this may have occurred about a century ago when Sgr A* brightened by about a factor of a million. Chandra and other X-ray missions have seen evidence of an X-ray “light echo” reflecting off nearby clouds, providing a measure of the brightness and timing of the flare.
“This would be a sudden end to the planet’s life, a much more dramatic fate than the planets in our solar system ever will experience,” Zubovas said.
Very long observations of Sgr A* will be made with Chandra later in 2012 that will give valuable new information about the frequency and brightness of flares and should help to test the model proposed here to explain them. The team said this work could improve understanding about the formation of asteroids and planets in the harsh environment of Sgr A*.
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.
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.
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.
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.
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.
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.
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.
Crater in Shadow on Vesta. This new image from Dawn in its low altitude mapping orbit on Dec. 13 shows part of the rim of a fresh crater on Vesta located in an area known as the Heavily Cratered Terrain in the northern hemisphere at around 17 degrees latitude and 77 degrees longitude. It was obtained at an altitude of 119 miles (191 km) and covers an area 11 mi x 11 mi (18 km x 18 km). Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
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NASA’s Dawn spacecraft has swooped down to the closest orbit above the monster asteroid Vesta that the craft’s cameras and spectrometers will ever glimpse and the probe has begun transmitting these highest resolution pictures to anxiously waiting scientists back on Earth.
Dawn arrived at its Low Altitude Mapping Orbit, known as LAMO, on Dec. 12, 2011 and will continue circling scarcely 130 miles (210 kilometers) above Vesta for at least the next 10 weeks. Each orbit takes about 4.3 hours.
NASA has now released the first batch of crisp new close-ups images taken by the Framing Camera on Dec. 13 showing the stippled and lumpy surface in an exquisitely fine detail never seen before.
The photo montage below shows side by side views of the same portion of the Vestan surface at ever increasing resolution and clarity from ever lower altitudes.
Closer and Closer to the Vesta Surface
NASA’s Dawn spacecraft has spiraled closer and closer to the surface of the giant asteroid Vesta since arriving in mid-2011. The two images on the left represent an identical area, first observed during Dawn's survey orbit (far left image). The picture in the center is from Dawn's high-altitude mapping orbit (HAMO) from an altitude of about 430 miles (700 km) with about 230 feet (70 meters-per-pixel) resolution. The image at right was obtained on Dec. 13 from the low altitude mapping orbit (LAMO) at an altitude of 124 miles (199 km) above the surface and has a resolution of 75 feet (23 m) per pixel. It shows small impact craters or slumping at the steep-flanked mountain in the image center that can be identified in the two images to the left. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
The high resolution image gallery reveals fine scale highlights such as multitudes of small craters, grooves and lineaments, landslides and slumping, ejecta from past colossal impacts, and small outcrops of bright and dark materials.
The science team, led by Principal Investigator Prof Chris Russell of UCLA, believes that Vesta is actually more like a planet than an asteroid based on the data obtained thus far.
“Vesta is the smallest terrestrial planet in our Solar System”, Russell told Universe Today. “We do not have a good analog to Vesta anywhere else in the Solar System.”
The primary science objectives at the LAMO orbit are to measure the elemental abundances on the surface of Vesta with the US built gamma ray and neutron detector (GRaND) and to probe the interior structure of the asteroid by measuring the gravity field.
Vesta is a proto-planet formed just a few million years after the birth of the solar system whose evolution into a larger planet was stopped cold by the massive gravitational influence of the planet Jupiter.
Scientists are plowing through thousands of images and millions of spectral measurements to glean clues about the origin and evolution of the solar system that have been preserved on the hitherto unexplored world.
Buried Craters on Vesta
This Dec. 13 image from Dawn spacecraft in its low altitude mapping orbit shows many buried craters located within the equatorial trough region of Vesta. This area bears traces of the material thrown out by the impact that created the Rheasilvia basin in the asteroid’s south polar region. Lineated features are visible in a variety of shapes and sizes from an altitude of 117 miles (189 km) over an area of 11 mi x 11 mi (18 km x 18 km). Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
“Vesta is a transitional body between a small asteroid and a planet and is unique in many ways,” says mission scientist Vishnu Reddy of the Max Planck Institute for Solar System Research in Katlenburg-Lindau, Germany. “Vesta is unlike any other asteroid we have visited so far.”
After completing the LAMO measurements, Dawn will again spiral back to a higher altitude for further data gathering especially at the unseen North Pole which is in darkness now.
Dawn will continue orbiting Vesta until July 2012 when it will fire up its ion propulsion system and depart for Ceres, the largest body in the main Asteroid belt between Mars and Jupiter.
“What can be more exciting than to explore an alien world that until recently was virtually unknown!” Dr. Marc Rayman told Universe Today. Rayman is Dawn’s Chief Engineer from NASA’s Jet Propulsion Lab (JPL) in Pasadena, Calif.
Equatorial Trough in Dark and Bright on Vesta
This image was one of the first obtained by Dawn in its low altitude mapping orbit and shows a part of one of the long troughs at the equator of Vesta. Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
“Dawn continues to gather gamma ray spectra and neutron spectra,” Rayman reports. “The bonus imaging at LAMO is yielding pictures more than three times better than those acquired in the high altitude mapping orbit (HAMO). Every week at this low altitude, Dawn will use its ion propulsion system to fine tune its orbit. The first of these weekly orbit adjustments was performed on December 17.”
The framing cameras eere built by the Max Planck Institute for Solar System Research in Germany.
A treasure trove of spectacular Vesta close-ups are streaming at this moment to the home planet and we’ll have many more goodies to show.
Holiday Greetings from an Alien Snowman on Vesta - to all inhabitants of the Galaxy
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Celebrate the winter holiday season in the company of an ‘Alien Snowman’ on the asteroid Vesta, someone we didn’t even have a clue about until six months ago.
Vesta and the Snowman have been transformed into the beautiful banner above – sent to me courtesy of the Dawn mission team to share with the readers of Universe Today.
Now you can be a creative artist and use the striking new images of Vesta to fashion your own greeting cards (see below) and send seasonal tidings of winter holiday cheer not possible before – all thanks to the remarkably insightful discoveries of Dawn’s international science team.
Vesta Greeting Card created by Joe W - From Dawn website
The Dawn spacecraft orbiting the giant asteroid Vesta is one of NASA’s crowning scientific accomplishments of 2011 because it’s cameras and spectrometers have unveiled a mysteriously diverse world that has no match elsewhere in our solar system.
The more we explore the unknown the more we are enlightened as to just how limited our view of the Universe is from within the narrow confines of our miniscule abode.
Vesta Greeting Card created by Judy C - From Dawn website
Hey, Let's go skiing at the South Pole !
The Kepler Space Telescopes latest discoveries of Earth-sized worlds are just the latest examples guiding us to a clearer understanding of our place in the Universe.
Vesta Greeting Card created by Jillian S - From Dawn website
Here are just a few of the Vestan images you can masterfully decorate – the Snowman, The Mount Everest of Vesta and the cataclysmically bombarded South Pole.
Alien Snowman on Vesta
An impact structure on asteroid Vesta resembling a snowman. Credit: NASA
So, let you imaginations run wild with wintery scenes to match the majesty of this matchless world. The Dawn Education and Public Outreach (EPO) team has created several templates which you can access here
Of course you can also use any of the images posted at the Dawn mission website.
The Mount Everest of Vesta
Image of asteroid Vesta calculated from a shape model, showing a tilted view of the topography of the south polar region. This perspective shows the topography, but removes the overall curvature of Vesta, as if the giant asteroid were flat and not rounded. Credit: NASAShattered South Pole of Vesta
This Dawn framing camera image shows scarps, hummocky (eg. wavy/ undulating) terrain and impacts in Vesta's south polar region. Credit: NASA
And feel free to post your inspired creations here at Universe Today.
Vesta is the second most massive object in the main Asteroid Belt between Mars and Jupiter.
Dawn arrived in orbit at Vesta in July 2011 for the first ever close up studies of the shattered celestial body. Dawn will spend a year investigating Vesta before spiraling out towards Ceres, the largest asteroid.
Saturn's moons Rhea and Dione as seen by the Cassini spacecraft. Could this be a future view from Earth? Image credit: NASA/JPL/Space Science Institute
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In the fall of 2006, observers at the Catalina Sky Survey in Arizona found an object orbiting the Earth. At first, it looked like a spent rocket stage — it had a spectrum similar to the titanium white paint NASA uses on rocket stages that end up in heliocentric orbits. But closer inspection revealed that the object was a natural body. Called 2006 RH120, it was a tiny asteroid measuring just a few metres across but it still qualified as a natural satellite just like the Moon. By June 2007, it was gone. Less than a year after it arrived, it left Earth’s orbit in search of a new cosmic companion.
Now, astrophysicists at Cornell are suggesting that 2006 RH120 wasn’t an anomaly; a second temporary moon is actually the norm for our planet.
Temporary satellites are a result of the gravitational pull of Earth and the Moon. Both bodies pull on one another and also pull on anything else in nearby space. The most common objects that get pulled in by the Earth-Moon system’s gravity are near Earth objects (NEOs) — comets and asteroids are nudged by the outer planets and end up in orbits that bring them into Earth’s neighbourhood.
Near Earth object Eros, the type of object that could be a second satellite. Image credit: NASA
The team from Cornell, astrophysicists Mikael Granvik, Jeremie Vaubaillon, Robert Jedicke, has modeled the way our Earth-Moon system captures these NEOs to understand how often we have additional moons and how long they stick around.
They found that the Earth-Moon system captures NEOs quite frequently. “At any given time, there should be at least one natural Earth satellite of 1-meter diameter orbiting the Earth,” the team said. These NEOs orbit the Earth for about ten months, enough time to make about three orbits, before leaving.
Luckily, and very interestingly, this discovery has implication well beyond academic applications.
Knowing that these small satellites come and go but that one is always present around the Earth, astronomers can work on detecting them. With more complete information on these bodies, specifically their position around the Earth at a given time, NASA could send a crew out to investigate. A crew wouldn’t be able to land on something a few metres across, but they could certainly study it up close and gather samples.
Close up image of asteroid 243 Ida. Image credit: NASA/courtesy of nasaimages.org
Proposals for a manned mission to an asteroid have been floating around NASA for years. Now, astronauts won’t have to go all the way out to an asteroid to learn about the Solar System’s early history. NASA can wait for an asteroid to come to us.
If the Cornell team is right and there is no shortage of second satellites around the Earth, the gains from such missions increases. The possible information about the solar system’s formation that we could obtain would be amazing, and amazingly cost-efficient.
