A new analysis of data suggests that the asteroid Lutetia is a leftover fragment from the same original material that formed the Earth, Venus and Mercury.
NASA’s Deep Space Network has captured a radar image of asteroid 2005 YU55, set to buzz past the Earth tomorrow.
Watch asteroid 2005 YU55 buzz the Earth tomorrow with your backyard telescope.
Astronomers prepare for an asteroid fly-by on November 8, using the Earth as the spacecraft.
Large enough to cause regional devastation if it were to hit the Earth, 2005 YU55 is the closest pass by an asteroid this big since 1976, and there won’t be another until 2028. The near miss provides an unparallelled opportunity for radar, optical and infrared observations of a mysterious charcoal-black world similar to the type of asteroid that astronauts may one day set foot on.
Radar bonanza “It’s a bit like a spacecraft fly-by with the Earth being the spacecraft,” says astronomer Don Yeomans at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California. “It’s going to be an extraordinary target for radar.”
Amateur astronomers discover near Earth asteroid.
The Dawn scientists have released another spectacular image of the south polar mountain on Vesta whose relative size is three times that of Mount Everest. More information about the image can be found here. From the caption:
The peak of Vesta’s south pole mountain, seen in the center of the image, rises about 13 miles (22 kilometers) above the average height of the surrounding terrain. Another impressive structure is a large scarp, a cliff with a steep slope, on the right side of this image. The scarp bounds part of the south polar depression, and the Dawn team’s scientists believe features around its base are probably the result of landslides.
It appears the light gravity on Vesta allows for the formation of extreme topology.
Dawn begins close-up orbit observations of Vesta. More new results here.
In this orbit, the average distance from the spacecraft to the Vesta surface is 420 miles (680 kilometers), which is four times closer than the previous survey orbit.
Data from the infrared telescope WISE has now identified ninety percent of the largest near-Earth asteroids.
NASA researchers also downgraded their estimate of the number of medium-sized asteroids, saying there are 44 percent fewer than previously believed. The downside is that scientists have yet to find many of these mid-sized asteroids, which could destroy a metropolitan city.
The WISE space telescope has raised questions about source of the asteroid believed to have killed the dinosaurs.
NASA has released an update summarizing what scientists have found since Dawn went into orbit around Vesta in July. The video below, compiled from images Dawn has taken, gives a nice visual overview. The most interesting big feature, understated by the video, is the series of grooves that appear to encircle the asteroid’s equator. To my eye it almost looks like Vesta was once two asteroids that got merged into one, with these grooves indicating the weld point.
The direct link to the video can be found here.
Embedded video from
NASA Jet Propulsion Laboratory California Institute of Technology
Astronomers plan one last close look at 1,900-foot-wide asteroid before sending a space probe there to collect samples.
Discovered in 1999, the OSIRIS-REx target asteroid, designated 1999 RQ36, nears Earth once every six years. During the 2011 closest approach in early September, it will be 10.9 million miles (17.5 million kilometers) away. In 1999, closest approach was 1.4 million miles (2.3 million kilometers).
Strangely, the article above never mentions the fact that 1999 RQ36 has 1 in a 1000 chance of hitting the Earth in 2182, which to my mind is the primary reason for studying it.
Asteroid dust from Hayabusa have been linked to the origin of the most common meteorite types found on Earth.
Want to mine an asteroid? Rather than travel to it with all their mining equipment, three Chinese scientists have proposed a better way. In a paper published today on the Los Alamos astro-ph preprint website, they have calculated the energy required to shift the orbits of the six thousand near-Earth asteroids and place them in Earth orbit for later mining. Of these, they found 46 asteroids that had the potential for such an operation, and two likely candidates for a space mission. One 30-foot-wide asteroid, 2008EA9, will actually be in the right place for this technique in 2049. As they write,
It can be seen that the velocity increment of the 2008EA9 is relatively small (-1.00km/s) and it will very close approach [approximately 645,000 miles] to the Earth in [February] 2049. Moreover the size of the NEO 2008EA9 is very small so that the capturing of it is relatively easy.
The real problem, of course, is adding that small “velocity increment” to the asteroid.
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Below the fold are two images released today, one from Dawn at Vesta and the other from Messenger at Mercury. What makes them interesting to me is that, though the surfaces of both Vesta and Mercury are crater-packed, there are definitely distinct differences between them that one can spot if you look closely, all highlighting the fundamentally different environments of both worlds.
First, the Vesta photograph. The image looks out past the asteroid’s horizon, showing clearly that this dwarf planet is not spherical, with the south pole depression that puzzles scientists just on the planet’s limb. The parallel long deep grooves that are associated with this depression can be seen on the right. Notice also that the inside walls of all the craters slope downward in a very shallow manner. This gives the impression that the impacts that formed these craters smashed into an almost beachlike sandy surface. Note too the that the center of some craters have what appear to be flat small “ponds,” a phenomenon seen by the spacecraft NEAR when it orbited the asteroid Eros. These ponds are not liquid, but are actually made up of fine-grained particles that settle in the hollows of the asteroid.
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In a paper published today on the Los Alamos astro-ph preprint website, two Chinese scientists have proposed using a solar sail for deflecting any asteroid that happens to be aimed at the earth. The diagram to the right is their simulated mission to impact the asteroid Apophis, which will pass close to the earth in 2029 and — depending on whether that flyby puts it through a very small 600 meter-wide mathematical “keyhole” — could then return in 2036 on a collision course.
The idea is to use the sail to slow the spacecraft down enough so that it starts to fall towards the sun. The sail is then used to maneuver it into a retrograde orbit. When it impacts the asteroid the impact will therefore be similar to a head-on collision, thereby imputing the most energy in the least amount of time with the least amount of rocket fuel. In their Apophis simulation, a mission, weighing only 10 kilograms (about 22 pounds), launched around 2025, and hitting the asteroid in this manner in 2026, would deflect its flyby in 2029 enough to guarantee it will not fly through the “keyhole” and therefore eliminate any chance of it hitting the earth in 2036.
Obviously many questions must be answered before such a mission should fly.
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The images from Dawn keep rolling in. The picture on the right, released two days ago, shows the asteroid’s terminator. What makes it intriguing is the weird looking crater near the bottom of the image. It appears to have formed at impact on the wall of a cliff, something that at first glance seems impossible.
This is what I think happened: The impactor sliced down the wall of the cliff, but because of Vesta’s low gravitational field the impact scar never collapsed downward, filling in.
I once wrote an article about asteroids for Astronomy where I described these objects as having the consistency of mashed potatoes and ice cream sundaes. This image illustrates this nicely. The asteroid’s weak gravitational field limits the density of its material, so that puffy strange formations such as this crater can form.
The mystery of Vesta’s south pole depression.
The Dawn mission team released another image today of the giant asteroid Vesta, this time taken from about 2,300 miles away. At this distance the resolution is still somewhat coarse, with the smallest visible detail about 0.43 miles in size.
To the right is a cropped section of the full image, focusing in on what appears to be a very strange geological feature, indicated by the arrows. From what I can tell, the dark meandering streak looks like a rille or flow coming out of the mound or peak near the bottom of the image. Yet, this dark meander continues directly across a crater as if it were a wind-blown dust streak.
I really have no idea what geological process created this. I also suspect that the scientists don’t quite know yet either, though I am sure they have some good theories, mostly based on the very light gravity that should exist on a world only 330 miles in diameter. As I’ve already noted, however, it is going to take them a couple of months to digest the data they are getting and come up with some reasonable conclusions. It will be fun to finally find out what they have learned.
The Dawn science team today released what they are calling “the first full-frame image” of Vesta. The image is shown below the fold.
The picture was taken from 3,200 miles, and shows a pockmarked irregularly shaped world. While many features that resemble the Moon (the craters, the rays radiating out from those craters), that Vesta itself is not spherical makes it very much unlike the Moon. It is probably going to take scientists several months at least to decipher the data they are getting and come up with some concrete conclusions about this strange dwarf planet.
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The story of Hayabusa, the Japanese space probe that was the first to successfully return material from an asteroid despite serious technical failures, has now inspired three major movies.
Astronomers have spotted the first Trojan asteroid to the Earth.
The asteroid is roughly 1,000 feet (300 meters) in diameter. It has an unusual orbit that traces a complex motion near a stable point in the plane of Earth’s orbit, although the asteroid also moves above and below the plane. The object is about 50 million miles (80 million kilometers) from Earth. The asteroid’s orbit is well-defined and for at least the next 100 years, it will not come closer to Earth than 15 million miles (24 million kilometers).
In a piece today at the Huffington Post, science journalist Seth Borenstein declares the wonders of NASA’s next mission: to send astronauts to an asteroid by 2025, as declared by President Obama.
If you believe this is going to happen, then I have a bridge I want to sell you. To do it we need a spaceship in which people can live for at least a year, and a rocket to get that ship into orbit. Not only do we not yet know how to build such a spaceship, we no longer have the capability of putting it into orbit. In case you’re unaware (Borenstein acts like he is), the space shuttle no longer exists. And under this administration and Congress, any replacement we get isn’t going to be able to launch such an interplanetary spaceship anywhere in the near future, especially faced as we are with the present federal debt.
The disgraceful thing about this article, however, is the lack of skepticism shown by Borenstein.
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A new image of Vesta from Dawn.
Some good news: Dawn has returned its first sharp close-up image of Vesta.
The image to below the fold is to me a relief, as it shows that the spacecraft’s camera is fine and that my engineering friends were correct in telling me so. Forgive me for being a skeptical and nervous reporter.
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Dawn enters orbit around Vesta.
A new analysis of the orbits of Ceres and Vesta says that in a surprisingly short time those orbits become chaotic and therefore unpredictable. More significantly, those orbits interact with the Earth’s and also make its long term orbit chaotic and unpredictable. From the abstract:
Although small, Ceres and Vesta gravitationally interact together and with the other planets of the Solar System. Because of these interactions, they are continuously pulled or pushed slightly out of their initial orbit. Calculations show that, after some time, these effects do not average out. Consequently, the bodies leave their initial orbits and, more importantly, their orbits are chaotic, meaning that we cannot predict their positions. The two bodies also have a significant probability of impacting each other, estimated at 0.2% per billion year. Last but not least, Ceres and Vesta gravitationally interact with the Earth, whose orbit also becomes unpredictable after only 60 million years. This means that the Earth’s eccentricity, which affects the large climatic variations on its surface, cannot be traced back more than 60 million years ago. This is indeed bad news for Paleoclimate studies. [emphasis mine]
The scientists found that it became impossible to calculate the orbits of the two largest asteroids after only several ten thousand years. They also found that “numerous asteroids in the main belt will behave in the same way with . . . much more chaotic behavior than previously thought.” Worse, the possibility of collisions was far higher than ever thought. Ceres and Vesta have a 1 in 500 chance of colliding with each other every billion years, while other asteroids have chances as low as 1 in 1000.
The importance of this discovery, which still needs to be confirmed by other researchers, cannot be understated.
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Another image of Vesta from Dawn has been released. This image was taken on July 9 from a distance of 26,000 miles away. It is definitely an improvement over the previous image, with more small details becoming visible. However, I once again wonder about the softness of the image. Look at the limb of the planet. It is soft against the black sky. This is not what one would expect from perfectly focused camera.
Dawn goes into orbit around Vesta next week. We sure learn then for sure if there is a problem with its camera, or whether I am merely being a bit too nervous.
