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Meteorites

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California meteorite is rare rock laden with organics - space - 01 May 2012. Read more: "Meteorite hunters: Join the space rock rush" A meteorite that landed in northern California last week is much more valuable than scientists first thought.

California meteorite is rare rock laden with organics - space - 01 May 2012

After the meteor was sighted streaking through the sky on 22 April, meteorite hunters found fragments of the rock, identified by the "fusion crust" that forms when it burns in the atmosphere. NASA and the SETI Institute in Mountain View, California, also mobilised a search team last weekend of about 30 scientists to look for the fragile black rocks. The meteorite turns out to be a very rare type of rock called CM chondrite, which makes up less than 1 per cent of the meteorites that fall to Earth. Bill Cooke of NASA's Meteoroid Environment Office at the Marshall Space Flight Center in Huntsville, Alabama, says it is not clear whether it is rare because it easily burns up in the atmosphere or there are just fewer of these rocks in space. More From New Scientist Space elevator trips could be agonisingly slow (New Scientist) Ancient impact of a gargantuan asteroid in South Australia changed the face of the world forever, study reveals.

Six-mile wide rock hit 300million years ago and left 120 mile impact zoneIt is the third largest asteroid impact site on the planetSeismic shock and fireball would have 'incinerated large parts of Earth' By Damien Gayle Published: 16:59 GMT, 19 February 2013 | Updated: 17:11 GMT, 19 February 2013 A gargantuan asteroid which struck Australia more than 300million years ago changed the face of the Earth forever, a new study claims.

Ancient impact of a gargantuan asteroid in South Australia changed the face of the world forever, study reveals

The six-mile diameter asteroid left an impact zone more than 120 miles wide - the third largest such site on the planet - and likely led to mass extinctions worldwide. 'The dust and greenhouse gases released from the crater, the seismic shock and the initial fireball would have incinerated large parts of the Earth,' said Andrew Glikson, visiting fellow at the Australian National University.

World's third largest asteroid impact zone found in South Australia. An asteroid measuring up to 20km across hit South Australia up to 360 million years ago and left behind the one of the largest asteroid impact zones on Earth, according to new research published today.

World's third largest asteroid impact zone found in South Australia

The impact zone in the East Warburton Basin was buried under nearly four kilometres of earth, said Dr Andrew Glikson, a visiting fellow to the Australian National University’s Planetary Science Institute and a co-author of the paper. “It’s significant because it’s so large. It’s the third largest impact terrain anywhere on Earth found to date,” Dr Glikson said. “It’s likely to be part of a particular cluster that was linked with a mass extinction event at that time.” Dr Glikson published his findings in a paper in the journal Tectonophysics, co-authored by ANU colleagues Dr John Fitzgerald and Dr Erdinc Saygin and by the University of Queensland’s Dr Tonguc Uysal. Collision Course: A Brief Guide to Earth’s Most Interesting Impact Craters. A Norwegian family arrived at their cabin to open it up for the spring and found a surprise: a large rock had smashed through the roof.

It was identified as a 1.3 pound breccia meteorite. It didn't hurt anybody, and its sale price should easily cover the damage to the roof; meteorites are valuable to collectors. But although most meteorites are very small, and to date nobody has been more than bruised by one, some of them are big and make a violent impression where they hit. Here are a few of the more interesting impact craters around: Barringer Crater, Arizona, USA View Larger Map Also known as "Meteor Crater," this was the first crater identified, due to its relatively pristine appearance. Obolon' Crater, Poltava Oblast, Ukraine View Larger Map Not all craters are so obvious; sometimes their structure is only apparent in aerial views.

Meteorite. Hoba meteorite: the largest known intact meteorite.

Meteorite

It was discovered in Namibia A meteorite is a solid piece of debris, from such sources as asteroids or comets, that originates in outer space and survives its impact with the Earth's surface. It is called a meteoroid before its impact. A meteorite's size can range from small to extremely large. When a meteoroid enters the atmosphere, friction, pressure, and chemical interactions with the atmospheric gases cause it to heat up and radiate that energy, thus forming a fireball, also known as a meteor or shooting/falling star. More generally, a meteorite on the surface of any celestial body is a natural object that has come from outer space. Meteorites have traditionally been divided into three broad categories: stony meteorites are rocks, mainly composed of silicate minerals; iron meteorites that are largely composed of metallic iron-nickel; and, stony-iron meteorites that contain large amounts of both metallic and rocky material.

Meteoroid. A meteoroid is a small rocky or metallic body travelling through space.

Meteoroid

Meteoroids are significantly smaller than asteroids, and range in size from small grains to 1 meter-wide objects. Smaller objects than this are classified as micrometeoroids or space dust.[1][2][3][4] Most are fragments from comets or asteroids, while others are collision impact debris ejected from bodies such as the Moon or Mars.[5][6][7][8] When such an object enters the Earth's atmosphere, it heats up from atmospheric friction and produces a streak of light, both from the glowing object and the trail of glowing particles that it leaves in its wake.

This phenomenon is called a meteor, or colloquially a "shooting star" or "falling star". A series of many meteors appearing seconds or minutes apart, and appearing to originate from the same fixed point in the sky, is called a meteor shower. Around 15,000 tonnes of meteoroids, micrometeoroids and different forms of space dust enter Earth's atmosphere each year.[9]