Tag: asteroids

The recently reactivated WISE space telescope has discovered its first new asteroid.

3:31 pm

The recently reactivated WISE space telescope has discovered its first new asteroid.

2013 YP139 is about 27 million miles (43 million kilometers) from Earth. Based on its infrared brightness, scientists estimate it to be roughly 0.4 miles (650 meters) in diameter and extremely dark, like a piece of coal. The asteroid circles the sun in an elliptical orbit tilted to the plane of our solar system and is classified as potentially hazardous. It is possible for its orbit to bring it as close as 300,000 miles from Earth, a little more than the distance to the moon. However, it will not come that close within the next century.

WISE, renamed NEOWISE by NASA, is expected to come up with a lot more of these in the coming years.

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WISE, the Wide Field Infrared Survey Explorer, sent back its first images in almost three years this week.

5:57 pm

Back from the dead: WISE sent back its first images in almost three years this week.

The Near-Earth Object Wide-field Infrared Survey Explorer spacecraft, or NEOWISE, has taken its first set of test images since being reactivated in September after a 31-month-long hibernation, NASA officials announced today (Dec. 19). The space agency wants NEOWISE to resume its hunt for potentially dangerous asteroids, some of which could be promising targets for future human exploration.

We should note that NASA had shut down this functional space telescope even though the cost to use it to hunt asteroids would be relatively little. Cost was cited as the reason, but I suspect it was a combination of the vast overruns for the James Webb Space Telescope and the Obama administration’s puzzling hostility to science at NASA.

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Hubble spots an asteroid spout six comet-like tails.

9:42 am

Hubble spots an asteroid spout six comet-like tails.

Astronomers viewing our solar system’s asteroid belt with NASA’s Hubble Space Telescope have seen for the first time an asteroid with six comet-like tails of dust radiating from it like spokes on a wheel. Unlike all other known asteroids, which appear simply as tiny points of light, this asteroid, designated P/2013 P5, resembles a rotating lawn sprinkler. Astronomers are puzzled over the asteroid’s unusual appearance.

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The accumulated evidence from the Chelyabinsk meteorite now suggests the risk of large asteroid impacts might be ten times greater than previously estimated.

12:07 pm

The accumulated evidence from the Chelyabinsk meteorite now suggests the risk of large asteroid impacts might be ten times greater than previously estimated.

The Chelyabinsk asteroid had approached Earth from a region of the sky that is inaccessible to ground-based telescopes. In the 6 weeks before the impact, it would have been visible above the horizon only during the daytime, when the sky is too bright to see objects of its size, says Borovička.

β€œThe residual impact risk β€” from asteroids with yet-unknown orbits β€” is shifting to small-sized objects,” says Peter Brown, a planetary scientist at the University of Western Ontario in London, Canada, and an author on the Nature papers.

Of the millions of estimated near-Earth asteroids 10–20 metres in diameter, only about 500 have been catalogued. Models suggest that an object the size of the Chelyabinsk asteroid hits Earth once every 150 years on average, Brown says. But the number of observed impacts exceeding 1 kiloton of TNT over the past 20 years alone hints at an actual impact risk that may be an order of magnitude larger than previously assumed,

The data also now suggests that the Chelyabinsk asteroid was twice as big as previously thought, and that it had an almost identical orbit to a much larger already known asteroid.

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Students crash rockets into the ground on purpose! With video.

9:25 am

Students crash rockets into the ground on purpose! With video.

In what at first glance seems like a terrible sense of direction, in March students from the University of Washington fired rockets from kites and balloons at an altitude of 3,000 ft (914 m) straight into the ground at Black Rock, Nevada: a dry lake bed in the desert 100 mi (160 km) north of Reno. This may seem like the ultimate in larking about, but it’s actually a serious effort to develop new ways of collecting samples from asteroids.

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A remotely operated Russian telescope, located in New Mexico, on Wednesday discovered a kilometer wide Near Earth asteroid.

7:09 pm

Boom! A remotely operated Russian telescope, located in New Mexico, on Wednesday discovered a kilometer wide Near Earth asteroid.

The asteroid, believed to be the 704th largest with an orbit that comes relatively near Earth, does not pose a danger of crashing into our planet, said the head of the observatory that made the discovery. β€œIt’s a big asteroid, but it poses no danger for us,” Leonid Elenin, who lives in the Moscow Region, told RIA Novosti on Friday.

Finding a new asteroid like this illustrates that there might be other such large objects out there undiscovered. Also cool is how the Russians discovered it, using equipment in the United States!

Posted from Midland, Texas, the center of the world for the American oil industry.

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Astronomers have found evidence of the remains of an exoplanet that they think was once wet and rocky.

6:12 pm

Astronomers have found evidence of the remains of an exoplanet that they think was once wet and rocky.

Using observations obtained with the Hubble Space Telescope and the large telescopes of the W. M. Keck Observatory , they found an excess of oxygen – a chemical signature that indicates that the debris had once been part of a bigger body originally composed of 26 per cent water by mass. By contrast, only approximately 0.023 per cent of the Earth’s mass is water.

From what I can gather, the actual data here is somewhat skimpy, requring a lot of assumptions for the scientists to come to this conclusion. Nonetheless, the data is interesting and very tantalizing.

Posted from Memphis, Tennessee.

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Scientists in Egypt have found what they think is evidence of a comet impact from 28 million years ago.

10:39 am

Scientists in Egypt have found what they think is evidence of a comet impact from 28 million years ago.

The best part however is this:

At the centre of the attention of this team was a mysterious black pebble found years earlier by an Egyptian geologist in the area of the silica glass. After conducting highly sophisticated chemical analyses on this pebble, the authors came to the inescapable conclusion that it represented the very first known hand specimen of a comet nucleus, rather than simply an unusual type of meteorite.

Assuming this claim is confirmed it is a very significant discovery. As far as I know, no other specimens from a comet nucleus have been identified previously.

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Linking mass extinctions to the Sun’s journey in the Milky Way

12:53 pm

The Sun's orbit in the Milky Way

In a paper published today on the Los Alamos astro-ph preprint service, astronomers propose that as many as eleven past extinction events can be linked to the Sun’s passage through the spiral arms of the Milky Way. (You can download the paper here [pdf].)

A correlation was found between the times at which the Sun crosses the spiral arms and six known mass extinction events. Furthermore, we identify five additional historical mass extinction events that might be explained by the motion of the Sun around our Galaxy. These five additional significant drops in marine genera that we find include significant reductions in diversity at 415, 322, 300, 145 and 33 Myr ago. Our simulations indicate that the Sun has spent ~60% of its time passing through our Galaxy’s various spiral arms.

The figure on the right, from their paper, shows the Sun’s orbit in red over the last half billion years. The Sun’s present position is indicated by the yellow spot, and the eleven extinctions are indicated by the circles.

There are obviously a great deal of uncertainties in this conclusion. Most significantly, the shape and history of the Milky Way remains very much in doubt, especially since we reside within it and cannot really get a good look at it. Though in recent years astronomers have assembled a reasonable image of the galaxy’s shape — a barred spiral with two major arms and several minor ones — this picture includes many assumptions that could very easily be wrong.

Nonetheless, the paper’s conclusions are interesting.
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