Neatorama » comet

Comet Lovejoy, As Seen From Space

Alex — Thu, 29 Dec 2011 00:14:50 +0000

On December 21, 2011, International Space Station Commander Dan Burbank captured the spectacular sight of Comet Lovejoy as seen from 240 miles above the Earth. Take a look: Hit play or go to Link [YouTube]

A Future Close Encounter

Miss Cellania — Thu, 28 Jul 2011 15:36:53 +0000

Astronomers have discovered a new source of meteor showers, very likely from a comet, that may be coming to an Earth near you. While explaining why we shouldn’t panic at the news, Dr. Phil Plait gives us a great analogy for understanding meteor showers.

If the path of the comet intersects the orbit of the Earth, we plow through that material at the same time every year. Think of it this way: imagine a racetrack, and you are driving around it. Now also imagine a long line of gnats flying across the racetrack. You would drive through that line of bugs at the same point on the racetrack every time, right? OK, replace you with the Earth, the racetrack with the Earth’s orbit, and the bugs with debris shed off a comet. Since the Earth returns to the same point in its orbit every year, if there is cometary debris there, we’ll smack into it at roughly the same calendar day every year.

This loose stuff from the comet burns up in our atmosphere, and we get a meteor shower.

Find out more about the specific new information from the Cameras for Allsky Meteor Surveillance, or CAMS. at Bad Astronomy Blog. Link

Comet Dives into the Sun

Johnny Cat — Tue, 25 May 2010 01:53:25 +0000

Video Link (Courtesy NASA/Berkeley)

In this quick image compilation, assembled from para-Earth-orbiting spacecraft, a comet can be seen diving into the Sun’s lower atmosphere.

The video above is a compilation of images from the two STEREO spacecraft that orbit with the Earth, one ahead of the planet and the other behind. The configuration allows for nearly full, continuous coverage of the sun, increasing the chance of witnessing something like the kamikaze comet that they spotted in March.

Seeing comets and other small objects approach the sun is difficult because the objects are overwhelmed by the sun’s brightness. Scientists were able to track this one closer to the sun than ever, before it it burned up in the sun’s lower atmosphere.

“We believe this is the first time a comet has been tracked in 3-D space this low down in the solar corona,” Claire Raftery of the University of California, Berkeley said in a press release. The images were presented at the American Astronomical Meeting in Miami May 24.

It’s doubtful the Solar Dynamics Observatory got any footage, but at least we can view a noteworthy event such as this.

Link

Jupiter’s Temporary Moons

John Farrier — Wed, 16 Sep 2009 23:29:50 +0000

Sarah Zielinski writes in The Smithsonian that Jupiter, as the largest planet in our solar system, occasionally pulls comets into its orbit. Sometimes, as with comet Shoemaker-Levy 9 in 1994 (pictured), Jupiter’s gravity will even pull a comet into a direct impact. Zielinsky writes:

Astronomers from Japan and Northern Ireland, presenting their findings today at the European Planetary Science Congress, used observations of Comet Kushida-Muramatsu—from when it was discovered in 1993 and when it returned in 2001—to calculate the comet’s path over the previous century. They determined that the comet became a temporary moon when it entered Jupiter’s neighborhood in 1949. It made two full, if irregular, orbits around the planet, and then continued its travels into the inner solar system in 1962.

The researchers also predict that Comet 111P/Helin-Roman-Crockett, which circled Jupiter between 1967 and 1985, will again become a temporary moon and complete six loops around the planet between 2068 and 2086.

“The results of our study suggests that impacts on Jupiter and temporary satellite capture events may happen more frequently than we previously expected,” David Asher of Northern Ireland’s Armagh Observatory told the AFP.

Link

Photo: NASA

Did A Comet Wipe Out The Mammoths?

Miss Cellania — Fri, 02 Jan 2009 17:05:08 +0000

Scientists have long pondered an event 12,900 years ago that caused the disappearance of the Clovis people of North America and the extinction of large mammals such as the mammoth, mastodon, saber-toothed cat, and the North American camel. One theory is that a comet broke into fragments and showered burning material over the continent. Now there’s some evidence -a layer of nanodiamonds have been found at a layer of sediment buried 12,900 years ago. The diamonds could have only been formed by a high-pressure high-temperature event.

These diamonds are measured in nanometers — mere billionths of meters — and one of them would not suffice for an engagement ring unless the recipient had an extremely small finger. Indeed, these diamonds are visible only with the aid of the most advanced microscopes.

The wide distribution of the nanodiamonds could be a sign that the comet broke into pieces in space and that the fragments burned up explosively over a broad area of North America. The heat and pressure from the event transformed carbon on the planet’s surface into the tiny diamonds, the scientists said.

“Imagine these fireballs exploding in the air. A Clovis hunter standing and looking at these things would have seen a canopy of fire as these things came in and exploded,” said Allen West, a geophysicist and one of the paper’s co-authors. “There would have been no sound. There would have been massive explosions. Brilliant light, brighter than the sun. There would have been radiant heat — it would have been capable, at the very least, of giving him serious burns and, at the maximum, of incinerating him.”

This theory would explain the climate change at the time, when the warming planet was plunged into another, shorter ice age. Skeptics cite lack of a crater or other surface evidence in refuting the theory. Link -via Digg