Posted on by Nancy Atkinson

Scientists Come to a Conclusion: Asteroid Killed the Dinosaurs

Over the years, scientists have debated the cause of the mass extinction that wiped out the dinosaurs 65 million years ago. Now, a panel of 41 international experts says it’s official: a massive asteroid around 15 kilometers wide slamming into Earth at Chicxulub, Mexico is the culprit. After surveying a wide variety of evidence for the competing theories, the panel said the telling evidence was the structures preserved in the interior of the crater. Computer models predicted how much rock was vaporized or ejected by the impact. “Our work lets us visualize the astonishing events of the few minutes after impact,” said Dr. Penny Barton, who led the group. “The front of the asteroid hit the Earth while the far side was still out in the upper atmosphere, punching a hole though the Earth’s atmosphere.”

The Cretaceous-Paleogene extinction was one of the biggest in earth’s history and geologic evidence of the impact has been discovered in rock layers from this time period, around the world. While the impact is widely accepted as the cause for the mass extinction, some critics disagreed, saying, for example, that the microfossils from the Gulf of Mexico show that the impact occurred well before the extinction and could not have been its primary cause.

The massive volcanism that produced the Deccan traps of India around this time has also been proposed as the main cause of the extinction. But in the panel’s review, the computer models synthesized the geologic evidence that support the impact hypothesis. The models showed that such an impact would have instantly caused devastating shock waves, a large heat pulse and tsunamis around the globe.

Moreover, a release of larger amounts of dust, debris and gases would have led to a prolonged cooling of Earth’s surface, low light levels and ocean acidification that would have decimated photosynthesizing plants and the species that relied on them.

The asteroid is believed to have hit Earth with a force one billion times more powerful than the atomic bomb at Hiroshima. It would have blasted material at high velocity into the atmosphere, triggering a chain of events that caused a global winter, wiping out much of life on Earth in a matter of days.

“As the asteroid vaporized explosively,” said Barton, from the University of Cambridge in the UK, “it created a crater 30 km deep and 100 km across, with sides as high as the Himalayas. However within only two minutes the sides collapsed inwards and the deepest parts of the crater rebounded upwards to leave a wide, shallow hollow.

“These terrifying events led to darkness and a global winter, resulting in the extinction of more than 70% of known species. The tiny shrew-like mammals which were around at that time proved better adapted to survival than the cumbersome dinosaurs, and the removal of these dominant animals paved the way for the radiation of the mammals and eventual emergence of humans on Earth.”

The team’s paper was published in the journal Science.

Sources: University of Cambridge

Posted on by Jean Tate

Small Asteroids, Bread Flour, and a Dutch Physicist’s 150-year Old Theory

Itokawa, a dusty asteroid (Credit: JAXA)

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No, it’s not the Universe Puzzle No. 3; rather, it’s an intriguing result from recent work into the strange shapes and composition of small asteroids.

Images sent back from space missions suggest that smaller asteroids are not pristine chunks of rock, but are instead covered in rubble that ranges in size from meter-sized boulders to flour-like dust. Indeed some asteroids appear to be up to 50% empty space, suggesting that they could be collections of rubble with no solid core.

But how do these asteroids form and evolve? And if we ever have to deflect one, to avoid the fate of the dinosaurs, how to do so without breaking it up, and making the danger far greater?

Johannes Diderik van der Waals (1837-1923), with a little help from Daniel Scheeres, Michael Swift, and colleagues, to the rescue.

Rocks and dust on asteroid Eros (Credit: NASA)

Asteroids tend to spin rapidly on their axes – and gravity at the surface of smaller bodies can be one thousandth or even one millionth of that on Earth. As a result scientists are left wondering how the rubble clings on to the surface. “The few images that we have of asteroid surfaces are a challenge to understand using traditional geophysics,” University of Colorado’s Scheeres explained.

To get to the bottom of this mystery, the team – Daniel Scheeres, colleagues at the University of Colorado, and Michael Swift at the University of Nottingham – made a thorough study of the relevant forces involved in binding rubble to an asteroid. The formation of small bodies in space involves gravity and cohesion – the latter being the attraction between molecules at the surface of materials. While gravity is well understood, the nature of the cohesive forces at work in the rubble and their relative strengths is much less well known.

The team assumed that the cohesive forces between grains are similar to that found in “cohesive powders” – which include bread flour – because such powders resemble what has been seen on asteroid surfaces. To gauge the significance of these forces, the team considered their strength relative to the gravitational forces present on a small asteroid where gravity at the surface is about one millionth that on Earth. The team found that gravity is an ineffective binding force for rocks observed on smaller asteroids. Electrostatic attraction was also negligible, other than where a portion of the asteroid this is illuminated by the Sun comes into contact with a dark portion.

Fast backward to the mid-19th century, a time when the existence of molecules was controversial, and inter-molecular forces pure science fiction (except, of course, that there was no such thing then). Van der Waals’ doctoral thesis provided a powerful explanation for the transition between gaseous and liquid phases, in terms of weak forces between the constituent molecules, which he assumed have a finite size (more than half a century was to pass before these forces were understood, quantitatively, in terms of quantum mechanics and atomic theory).

Van der Waals forces – weak electrostatic attractions between adjacent atoms or molecules that arise from fluctuations in the positions of their electrons – seem to do the trick for particles that are less than about one meter in size. The size of the van der Waals force is proportional to the contact surface area of a particle – unlike gravity, which is proportional to the mass (and therefore volume) of the particle. As a result, the relative strength of van der Waals compared with gravity increases as the particle gets smaller.

This could explain, for example, recent observations by Scheeres and colleagues that small asteroids are covered in fine dust – material that some scientists thought would be driven away by solar radiation. The research can also have implications on how asteroids respond to the “YORP effect” – the increase of the angular velocity of small asteroids by the absorption of solar radiation. As the bodies spin faster, this recent work suggests that they would expel larger rocks while retaining smaller ones. If such an asteroid were a collection of rubble, the result could be an aggregate of smaller particles held together by van der Waals forces.

Asteroid expert Keith Holsapple of the University of Washington is impressed that not only has Scheeres’ team estimated the forces in play on an asteroid, it has also looked at how these vary with asteroid and particle size. “This is a very important paper that addresses a key issue in the mechanics of the small bodies of the solar system and particle mechanics at low gravity,” he said.

Scheeres noted that testing this theory requires a space mission to determine the mechanical and strength properties of an asteroid’s surface. “We are developing such a proposal now,” he said.

Source: Physics World. “Scaling forces to asteroid surfaces: The role of cohesion” is a preprint by Scheeres, et al. (arXiv:1002.2478), submitted for publication in Icarus.

Posted on by Nancy Atkinson

Asteroid Might be Visible to Naked Eye on Feb. 17

Asteroid Vesta as seen by NASA's Hubble Space Telescope. Image credit: NASA/ESA/U of Md./STSci/Cornell/SWRI/UCLA

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An asteroid could be visible with binoculars, or even the naked eye on Wednesday, February 17, 2010. No, it’s not coming close to Earth, although this second most massive object in the asteroid belt will be at its closest point to Earth in its orbit, about 211,980,000 kilometers (131,700,000 miles) away. Asteroid Vesta – one of the asteroids that the Dawn spacecraft will visit – will be at opposition on Wednesday, meaning it is opposite the sun as seen from Earth, and is closest to us. Vesta is expected to shine at magnitude 6.1, and that brightness should make it visible for those with clear skies and a telescope, but perhaps even those blessed with excellent vision and little or no light pollution. Vesta will be visible in the eastern sky in the constellation Leo, and will continue to be visible — although less so — in the coming months.

What makes this space rock so prominent these days? Along with its relative proximity at this point, a full half of the asteroid is being bathed by sunlight when seen from Earth, making it appear brighter. Another attribute working in the observer’s favor is that Vesta has a unique surface material that is not as dark as most main belt asteroids – allowing more of the sun’s rays to reflect off its surface.

For more info about observing Vesta, check out this article from Sky & Telescope.

If you get lucky enough to see Vesta, and want to learn more about it, check out this info on the Dawn mission website. Dawn is currently motoring its way through the asteroid belt, will begin its exploration of Vesta in the summer of 2011.

Source: JPL

Posted on by Nancy Atkinson

Hubble Takes A Look at Possible Asteroid Collision

Hubble Views of Comet-like Asteroid P/2010 A2. Credit: NASA, ESA, and D. Jewitt (UCLA)

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We reported earlier that on January 6, 2010, ground-based observatories may have spotted evidence of an asteroid collision in the asteroid belt. Now, the Hubble Space Telescope has taken a look at the mysterious X-shaped debris pattern and trailing streamers of dust. With Hubble’s sharp vision, astronomers believe a head-on collision between two asteroids has actually occured. Astronomers have long thought the asteroid belt is being ground down through collisions, but such a smashup has never been seen before.

“This is quite different from the smooth dust envelopes of normal comets,” said principal investigator David Jewitt of the University of California at Los Angeles. “The filaments are made of dust and gravel, presumably recently thrown out of the nucleus. Some are swept back by radiation pressure from sunlight to create straight dust streaks. Embedded in the filaments are co-moving blobs of dust that likely originated from tiny unseen parent bodies.”

Asteroid collisions would likely have an average impact speed of more than 11,000 miles per hour, or five times faster than a rifle bullet. The comet-like object imaged by Hubble, called P/2010 A2, was first discovered by the Lincoln Near-Earth Asteroid Research, or LINEAR, program sky survey on Jan. 6. New Hubble images taken on Jan. 25 and 29 show a complex X-pattern of filamentary structures near the nucleus.
Hubble shows the main nucleus of P/2010 A2 lies outside its own halo of dust. This has never been seen before in a comet-like object. The nucleus is estimated to be 460 feet in diameter.

Close-up of Comet-like Asteroid P/2010 A2. Credit: NASA, ESA, and D. Jewitt (UCLA)

Normal comets fall into the inner regions of the solar system from icy reservoirs in the Kuiper Belt and Oort Cloud. As a comet nears the sun and warms up, ice near the surface vaporizes and ejects material from the solid comet nucleus via jets. But P/2010 A2 may have a different origin. It orbits in the warm, inner regions of the asteroid belt where its nearest neighbors are dry rocky bodies lacking volatile materials.

This leaves open the possibility that the complex debris tail is the result of an impact between two bodies, rather than ice simply melting from a parent body.

“If this interpretation is correct, two small and previously unknown asteroids recently collided, creating a shower of debris that is being swept back into a tail from the collision site by the pressure of sunlight,” Jewitt said.

The main nucleus of P/2010 A2 would be the surviving remnant of this so-called hypervelocity collision.

“The filamentary appearance of P/2010 A2 is different from anything seen in Hubble images of normal comets, consistent with the action of a different process,” Jewitt said. An impact origin also would be consistent with the absence of gas in spectra recorded using ground-based telescopes.

The asteroid belt contains abundant evidence of ancient collisions that have shattered precursor bodies into fragments. The orbit of P/2010 A2 is consistent with membership in the Flora asteroid family, produced by collisional shattering more than 100 million years ago. One fragment of that ancient smashup may have struck Earth 65 million years ago, triggering a mass extinction that wiped out the dinosaurs. But, until now, no such asteroid-asteroid collision has been caught “in the act.”

At the time of the Hubble observations, the object was approximately 180 million miles from the sun and 90 million miles from Earth. The Hubble images were recorded with the new Wide Field Camera 3 (WFC3).

Source: HubbleSite

Posted on by Nancy Atkinson

WISE Bags its First Near-Earth Asteroid

The red dot at the center of this image is the first near-Earth asteroid discovered by NASA's Wide-Field Infrared Survey Explorer, or WISE Image credit: NASA/JPL-Caltech/UCLA

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Well, that didn’t take long: The WISE spacecraft (Wide-field Infrared Survey Explorer) spotted its first near-Earth asteroid on January 12, 2010, two days before the official start of its all-sky survey. That’s a pretty good catch, considering WISE just popped it lens cover a couple of weeks ago (December 29, 2009) and released its “first light” image on January 6. This is the first of what researchers hope will be thousands of previously undiscovered asteroids in the main asteroid belt, and hundreds of new near-Earth asteroids. By mapping the whole sky in infrared light, it should also be able to capture millions of new stars and galaxies.

WISE’s software picked up the object, 2010 AB78, moving against a background of stationary stars. Researchers followed up and confirmed the discovery with the University of Hawaii’s 2.2-meter (88-inch) visible-light telescope near the summit of Mauna Kea.

This asteroid does not pose any foreseeable impact threat to Earth, but scientists will continue to monitor it. 2010 AB78 is currently about 158 million kilometers (98 million miles) from Earth. It is estimated to be roughly 1 kilometer (0.6 miles) in diameter and circles the sun in an elliptical orbit tilted to the plane of our solar system. The object comes as close to the sun as Earth, but because of its tilted orbit, it is not thought to pass near our planet.

Source: JPL

Posted on by Nancy Atkinson

Asteroid Detection, Deflection Needs More Money, Report Says

Artists impression of an asteroid flying by Earth. Credit: NASA

Are we ready to act if an asteroid or comet were to pose a threat to our planet? No, says a new report from the National Research Council. Plus, we don’t have the resources in place to detect all the possible dangerous objects out there. The report lays out options NASA could follow to detect more near-Earth objects (NEOs) that could potentially cross Earth’s orbit, and says the $4 million the U.S. spends annually to search for NEOs is insufficient to meet a congressionally mandated requirement to detect NEOs that could threaten Earth. “To do what Congress mandated NASA to do is going to take new technology, bigger telescopes with wider fields,” said Don Yeomans, Manager of NASA’s Near Earth Object Program Office, speaking at the American Geophysical Union conference last month.

However, Yeomans said work is being done to improve the quality and quantity of the search for potentially dangerous asteroids and comets. “We have a long term goal to have three more 1.8 meter telescopes,” he said, “and the Large Synoptic Survey Telescope with an 8.4 meter aperture in 2016. Once these new facilities are in place, the data input will be like drinking from a fire hose, and the rate of warnings will go up by a factor of 40.”

But getting all these facilities, and more, online and running will take continued and additional funding.

Congress mandated in 2005 that NASA discover 90 percent of NEOs whose diameter is 140 meters or greater by 2020, and asked the National Research Council in 2008 to form a committee to determine the optimum approach to doing so. In an interim report released last year, the committee concluded that it was impossible for NASA to meet that goal, since Congress has not appropriated new funds for the survey nor has the administration asked for them.

But this issue isn’t and shouldn’t be strictly left to NASA, said former astronaut Rusty Schweickart, also speaking at the AGU conference. “There’s the geopolitical misconception that NASA is taking care of it,” he said. “They aren’t and this is an international issue.”

Schweickart said making decisions on how to mitigate the threat once a space rock already on the way is too late, and that all the decisions of what will be done, and how, need to be made now. “The real issue here is getting international cooperation, so we can — in a coordinated way — decide what to do and act before it is too late,” he said. “If we procrastinate and argue about this, we’ll argue our way past the point of where it too late and we’ll take the hit.”

But this report deals with NASA, and committee from the NRC lays out two approaches that would allow NASA to complete its goal soon after the 2020 deadline; the approach chosen would depend on the priority policymakers attach to spotting NEOs. If finishing NASA’s survey as close as possible to the original 2020 deadline is considered most important, a mission using a space-based telescope conducted in concert with observations from a suitable ground-based telescope is the best approach, the report says. If conserving costs is deemed most important, the use of a ground-based telescope only is preferable.

The report also recommends that NASA monitor for smaller objects, and recommends that immediate action be taken to ensure the continued operation of the Arecibo Observatory in Puerto Rico, and support a program at the Goldstone Deep Space Communications Complex. Although these facilities cannot discover NEOs, they play an important role in accurately determining the orbits and characterizing the properties of NEOs.

Schweikart quoted Don Yeomans as saying the three most important things about asteroid mitigation is to find them early, find them early and find them early.

“We have the technology today to move an asteroid,” Schweikart said. “We just need time. It doesn’t take a huge spacecraft to do the job of altering an asteroid’s course. It just takes time. And the earlier we could send a spacecraft to either move or hit an asteroid, the less it will cost. We could spend a few hundred million dollars to avoid a $4 billion impact.”

But the report put out by the NRC stresses the methods for asteroid/comet defense are new and still immature. The committee agreed that with sufficient warning, a suite of four types of mitigation is adequate to meet the threat from all NEOs, except the most energetic ones.

• Civil defense (evacuation, sheltering in place, providing emergency infrastructure) is a cost-effective mitigation measure for saving lives from the smallest NEO impact events and is a necessary part of mitigation for larger events.
• “Slow push” or “slow pull” methods use a spacecraft to exert force on the target object to gradually change its orbit to avoid collision with the Earth. This technique is practical only for small NEOs (tens of meters to roughly 100 meters in diameter) or possibly for medium-sized objects (hundreds of meters), but would likely require decades of warning. Of the slow push/pull techniques, the gravity tractor appears to be by far the closest to technological readiness.
• Kinetic methods, which fly a spacecraft into the NEO to change its orbit, could defend against moderately sized objects (many hundreds of meters to 1 kilometer in diameter), but also may require decades of warning time.
• Nuclear explosions are the only current, practical means for dealing with large NEOs (diameters greater than 1 kilometer) or as a backup for smaller ones if other methods were to fail.

Although all of these methods are conceptually valid, none is now ready to implement on short notice, the report says. Civil defense and kinetic impactors are probably the closest to readiness, but even these require additional study prior to reliance on them.

Source: National Research Council
Read the entire report

Posted on by Nancy Atkinson

Asteroids Zipping Too Close to Earth Can Experience Seismic Activity

Artist concept of an NEA.

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An asteroid’s orbit can be altered if it travels in the vicinity of Earth. But astronomers are finding the effects Earth has on space rocks go far beyond just orbital alterations. Richard Binzel of MIT says that Earth has considerable influence on asteroids — and from a distance much larger than previously thought. He has determined that if an near-Earth asteroid (NEA) travels within a certain range of Earth, roughly one-quarter of the distance between Earth and the moon, it can experience a “seismic shake” strong enough to bring bright, new regolith to its surface. This new finding has helped answer the question of how some asteroids appear to have fresh surfaces, as well as shedding new light on where most meteorites come from.

These rarely seen “fresh asteroids” have long interested astronomers because their spectral fingerprints, or how they reflect different wavelengths of light, match 80 percent of all meteorites that fall to Earth, according to a paper by Binzel appearing in the Jan. 21 issue of Nature. The paper suggests that Earth’s gravitational pull and tidal forces create these seismic tremors.

By hypothesizing about the cause of the fresh surfaces of some NEAs, Binzel and his colleagues have tried to solve a decades-long conundrum about why these fresh asteroids are not seen in the main asteroid belt, which is between Mars and Jupiter. They believe this is because the fresh surfaces are the result of a close encounter with Earth, which obviously wouldn’t be the case with an object in the main asteroid belt. Only those few objects that have ventured recently inside the moon’s orbital distance and have experienced a “fresh shake” match freshly fallen meteorites measured in the laboratory, Binzel said.

Binzel’s team telescopically collected information on NEAs, including a huge amount of spectral fingerprint data. Analyzing this data, the group examined where a sample of 95 NEAs had been during the past 500,000 years, tracing their orbits to see how close they’d come to Earth. They discovered that 75 NEAs in the sample had passed well inside the moon’s distance within the past 500,000 years, including all 20 fresh asteroids in the sample.

Binzel next determined that an asteroid traveling within a distance equal to 16 times the Earth’s radius (about one-quarter of the distance to the moon) appears to experience vibrations strong enough to create fresh surface material. He reached that figure based on his finding that about one-quarter of NEAs are fresh, as well as two known facts — that the space weathering process that ages regolith can happen in less than one million years, and that about one-quarter of NEAs come within 16 Earth radii in one million years.

Before now, people thought an asteroid had to come within one to two Earth radii to undergo significant physical change.

Many details about the shaking process remain unknown, including what exactly it is about Earth that shakes the asteroids, and why this happens from a distance as far away as 16 Earth radii. What is certain is that the conditions depend on complex factors such as the velocity and duration of the encounter, the asteroid’s shape and the nature of the preexisting regolith. “The exact trigger distance depends on all those seismology factors that are the totally new and interesting area for cutting edge research,” Binzel said.

Binzel also proposed a new field of study: asteroid seismology.

Further research might include computer simulations, ground observations and sending probes to look at the surfaces of asteroids. Binzel’s next steps will be to try to discover counterexamples to his findings or additional examples to support it. He may also investigate whether other planets like Venus or Mars affect asteroids that venture close to them.

Source: EurekAlert

Posted on by Nancy Atkinson

Asteroid Collision May Have Created Comet-like Object

P/2010 A imaged by Dr. Robert McMillan at Kitt Peak, Arizona. Credit: LINEAR

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A strange comet-like object discovered on January 6, 2010 may actually be the result of an asteroid collision. Lincoln Near-Earth Asteroid Research (LINEAR) sky survey in New Mexico spotted an object in the asteroid belt, called P/2010 A that looked “fuzzy,” with a tail like a comet rather than a speck of light like a normal asteroid. But comets don’t normally reside in the asteroid belt, and the object’s orbit is all wrong for a comet. While the asteroid belt is made up of debris from the “leftovers” of our solar system, and like the remains of early crashes between giant rocks, astronomers haven’t witnessed a collision before.

Other comet/asteroid crossbreeds have been seen previously, such as the Comet P/1996 N2 discovered in 1996, but astronomers are keeping a close eye on this latest oddball, as they believe the best explanation is that collision took place between two asteroids deep in space, about 250 million miles away from Earth. If they are right, it will be the first confirmed high-speed crash ever witnessed between massive space rocks.

Sky and Telescope reports that the comet specialists are hoping to observe the strange goings-on with both the Hubble and Spitzer space telescopes. Neither has been given the green light yet, but if/when that happens the observations would be made within the next few days.

Sources: Skymania, Sky & Telescope, Discovery Space

Posted on by Nancy Atkinson

Images and Videos of 2010 AL30

Series of 30 15" exposures tracking on 2010 AL30 between 07:18:16 and 07:27:29 GMT - Credit: Patrick Wiggins

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Amateur astronomers heeded the call of making observations of the small asteroid 2010 AL30, which whizzed by Earth today. Here are some of the great images and videos captured by the amateur astronomy community, which will help the professionals determine the exact orbit, and also perhaps what exactly this unusual asteroid is. The object, which has been estimated to be between 10-15 meters (30 -50 feet) across, is likely a natural object, but it hasn’t officially been ruled out that it might be man-made, i.e., a spent rocket booster, from perhaps the Venus Express mission. The folks who are apt to make the determination are those who work with the 70-meter radio dish at Goldstone. I corresponded with Lance Benner from the Goldstone facility, and he said, “We’re still working with the data so it’s still too early to say.”

We’ll keep you posted, but in the meantime, enjoy some of the images and videos of 2010 AL30’s flyby. Above, NASA Solar System Ambassador Patrick Wiggins in Utah took a series of exposures and combined them into a “movie.” He used a C-14 @ f/5.5 telescope and SBIG ST-10 binned 3×3 using a clear filter. The Field of View is about 18 x 26 arc minutes.

2010 AL30, on January 13, 2010. Credit: Ernesto Guido & Giovanni Sostero, Remanzacco Observatory.

This image was taken by 2010 AL30, on January 13, 2010 by Ernesto Guido & Giovanni Sostero, at the Remanzacco Observatory in Italy. Check out their website for more images.

The prospect of 2010 AL30 hitting Earth never even entered into the equation of this unusual asteroid. The problem, (if there is one) is that it was only detected two days ago. The other issue is its origin. The Italian astronomers who took the above image noted that the object has an orbital period of almost exactly one year and might be a man-made object. However, Alan Harris, senior researcher at the Space Science Institute countered by saying the object has a perfectly ordinary Earth-crossing orbit, and that its orbit doesn’t resemble any useful spacecraft trajectory. Additionally, NASA put out a press release yesterday saying the object was “a natural” asteroid.

“This object’s orbit reaches the orbit of Venus at its closest point to the sun and nearly out to the orbit of Mars at its furthest point, crossing the Earth’s orbit at a very steep angle,” the press release said. “This makes it very unlikely that 2010 AL30 is a rocket stage. Furthermore, trajectory extrapolations show that this object cannot be associated with any recent launch and it has not made any close approaches to the Earth since well before the Space Age began.”

continued below….

This is another video from Patrick Wiggins, this time with a smaller exposure time. “The target is pretty faint (not surprising for 1″ exposures) so you have to look close to see it as it moves from left to right,” he said. (Thanks to the SciBuff website for the video.)

But then, ESA mission analyst Michael Khan looked at data from the Venus Express mission, and he wrote in his blog that perhaps 2010 AL30 might be the Fregat upper stage of the rocket that sent Venus Express to Venus. Only more detailed analysis of data from the object will provide the answer.

This image was taken by Tavi Greiner, using the SLOOH robotic observatory on the Canary Islands, at 03:02 GMT. Check out SLOOH to find out how you can take your own images.

The initial word from Goldstone is that the object produced very strong radar echoes, and also that it had a very fast 9-minute rotation.

The trajectory of 2010 AL30. Credit: NASA's NEO program

The trajectory of 2010 AL30.

2010 AL30 imaged on January 12 from the distance of 0.003 7 AU at the Nazaret Observatory at the Canary Islands – Credit: Gustavo, Muler, Schteinman – Observatorio Nazaret, J47. Click on the image or here to see a “movie” of the object.

Check out more images on Spaceweather.com, including this image from Alberto Quijan Vodniza and Mario Rojas Pereira from the University of Narino- Columbia.

There’s also this very cool animation of 2010 AL30’s approach, and what Earth would look like to anyone “riding” on the asteroid.

Also, check out the Transient Sky blog, where Carl Hergenrother lays out the details what might have happened if 2010 AL30 had been headed for impact with Earth.

And one more thing, via the Bad Astronomer, is this great graphic showing how far away this object passed by Earth.

Sources: SciBuff, Emily Lakdawalla’s Planetary Blog, Spaceweather.com, Transient Sky

Posted on by Nancy Atkinson

Asteroid or Space Junk? Object Makes Close Pass by Earth Wednesday

Asteroid or rocket booster? 2010 AL30 as imaged remotely from Australia on Jan. 11, 2010. Credit: Ernesto Guido & Giovanni Sostero

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Caption: Asteroid or rocket booster? 2010 AL30 as imaged remotely from Australia on Jan. 11, 2010. Credit: Ernesto Guido & Giovanni Sostero, Remanzacco Observatory.

An unusual object will make a close flyby of Earth on Wednesday, coming within only 128,000 km (about 80,000 miles), or at a distance about three times less than the moon’s orbit. The object, named 2010 AL30, is about 10-15 meters long, and asteroid watchers say there is no chance it will hit the planet. But is it an asteroid or perhaps a piece of space junk, like a spent rocket booster?

UPDATE: The Solar System Dynamics website now says the object is an Apollo-type asteroid, which are Near-Earth asteroids that have orbits which cross the Earth’s orbit and pass approximately 1 AU or less from Earth.

According to Italian astronomers Ernesto Guido and Giovanni Sostero of the Remanzacco Observatory, who took this image (above) of 2010 AL30, it has an orbital period of almost exactly one year and might be a man-made object.

However, Alan Harris, senior researcher at the Space Science Institute said the object has a perfectly ordinary Earth-crossing orbit.

“Unlikely to be artificial, its orbit doesn’t resemble any useful spacecraft trajectory, and its encounter velocity with Earth is not unusually low,” he said.

The object make its closest approach at 12:48 GMT on Wednesday, and and amateur astronomers are encouraged to observe 2010 AL30 as a 14th magnitude star in the constellations of Orion, Taurus, and Pisces. Check here to get the ephemeris of the object from the Solar System Dynamics website.

Several observatories, including the Goldstone Radar will be observing NEO 2010 AL30 during its Earth flyby. After the January 13 close flyby, it will go too close to the Sun to be observed.

Sources: Remanzacco Observatory, Spaceweather.com