New images of Comet ISON suggest it might have begun breaking up.
New images of Comet ISON suggest it might have begun breaking up.
Tag: asteroids
Scientists have discovered a Kuiper Belt asteroid lighter than water.
Scientists have discovered a Kuiper Belt asteroid lighter than water.
Nor is the asteroid small, having a 400 mile diameter. It is thought is is made up mostly of ice, is not very densely packed, and is probably quite porous as well.
Hubble spots an asteroid spout six comet-like tails.
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.
The geology of Vesta as seen by Dawn appears to contradict the present models for that asteroid’s origin.
The uncertainty of science: The geology of Vesta as seen by Dawn appears to contradict the present models for that asteroid’s origin.
The accumulated evidence from the Chelyabinsk meteorite now suggests the risk of large asteroid impacts might be ten times greater than previously estimated.
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 BoroviΔka.
βThe residual impact risk β from asteroids with yet-unknown orbits β is shifting to small-sized objects,β 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 10β20 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.
Students crash rockets into the ground on purpose! With video.
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.
Hayabusa 2 test fires its cannon in preparation for its 2014-2018 asteroid sample return mission.
Hayabusa 2 test fires its cannon in preparation for its 2014-2018 asteroid sample return mission.
A newly discovered half-mile wide asteroid has 1 in 63,000 chance of hitting the Earth in 2032.
A newly discovered half-mile wide asteroid has 1 in 63,000 chance of hitting the Earth in 2032.
That’s the Russian report above, which on these matters tend to be panic-stricken. Here’s the JPL version, which downplays the concern.
Divers working at a Russian lake have recovered a half-ton piece of the asteroid that exploded over Chelyabinsk on February 15.
Divers working at a Russian lake have recovered a half-ton piece of the asteroid that exploded over Chelyabinsk on February 15.
A remotely operated Russian telescope, located in New Mexico, on Wednesday discovered a kilometer wide Near Earth asteroid.
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. βItβs a big asteroid, but it poses no danger for us,β 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.
Astronomers have found evidence of the remains of an exoplanet that they think was once wet and rocky.
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 β 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 Earthβs 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.
Scientists in Egypt have found what they think is evidence of a comet impact from 28 million years ago.
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.
The asteroid that might hit the Earth in 2880.
The asteroid that might hit the Earth in 2880.
Divers have pulled fragments from the February 15 Chelyabinsk meteorite impact out of nearby Chebarkul Lake.
Divers have pulled fragments from the February 15 Chelyabinsk meteorite impact out of nearby Chebarkul Lake.
Posted from Gaitlinburg, Tennessee, the Coney Island of the Smoky Mountains. The drive today was sadly a lot longer than planned, as we hit bad traffic in Nashville.
Linking mass extinctions to the Sun’s journey 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.
» Read more
Using photos from Dawn astronomers have now assembled an online atlas of the asteroid Vesta that the public can explore.
Using photos from Dawn astronomers have now assembled an online atlas of the asteroid Vesta that the public can explore.
NASA will reactivate the Wide-field Infrared Survey Explorer (WISE) next month to use it to look for more near Earth asteroids.
NASA will reactivate the Wide-field Infrared Survey Explorer (WISE) next month to use it to look for more near Earth asteroids.
This decision raises two thoughts.
- Why did they shut it down in the first place if it was still viable and could still do important research? If the cost wasn’t worth the benefit then, how has this equation changed now? And if the cost was worth the benefit, it then was foolish to shut it down in the first place. Though it costs money to operate these things, it is always cheaper to keep something running than to build something new. The press announcement above doesn’t really address these issues, and I wish it did.
- I wonder if this decision is somehow related to the end of the Kepler mission. With Kepler out of service, maybe NASA decided to shift the funds to run that telescope over to WISE. They do not say, but the timing is interesting. This decision could be a hint that Kepler doesn’t really have another mission it can fulfill, and thus the money to run it has already been put elsewhere.
Engineers have identified twelve asteroids that could be captured with today’s technology.
Engineers have identified twelve asteroids that could be captured with today’s technology.
Their number one most easily moved space rock is named 2006 RH120. A single rocket burn in 2021 would be enough to place this roughly 4-meter-wide asteroid into orbit around a Lagrange point by 2026. NASA could then launch people to study this object (which would barely be bigger than the astronauts themselves) and learn about its history.
An update on Dawn in its journey from the asteroids Vesta to Ceres.
An update on Dawn in its journey from the asteroids Vesta to Ceres. Bottom line:
Dawn is 18 million kilometers (11 million miles) from Vesta and 50 million kilometers (31 million miles) from Ceres. It is also 3.47 AU (519 million kilometers or 322 million miles) from Earth, or 1,310 times as far as the moon and 3.42 times as far as the sun today. Radio signals, traveling at the universal limit of the speed of light, take 58 minutes to make the round trip.
A graveyard of comets.
Even more interesting, some of these comets have risen from the dead!