* Astronomy

Blobrana · L

RE: Meteorites

Blobrana · L

Meteorites may have kick-started life on Earth by creating organic molecules as they slammed into the ocean, say Japanese scientists who have done laboratory experiments to test the idea.
Takeshi Kakegawa and colleagues at Tohoku University produced organic molecules under conditions replicating a meteorite hitting the sea. Their experiments validate a theory first proposed by the American astronomer Carl Sagan in the seventies, says Kakegawa. 'He just mentioned this hypothesis in one sentence in a paper, but he didn't do any experiments. Since then, many people have thought meteorites could produce organic molecules, but we are the first to succeed in showing this.'

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First Planets Lived Fast and Died Young
Surprising findings from some of the oldest known meteorites suggest that our solar system was once chock-full of miniature planets, complete with metallic cores and rocky crusts. The findings could force a rethinking of how the solar system and its constituent bodies evolved.

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Magnetism on the Angrite Parent Body and the Early Differentiation of Planetesimals
Angrites are among the oldest known pristine basaltic meteorites and record the earliest stages of planet formation and differentiation. Our paleomagnetic analysis of three angrites found that they record a past magnetic field of ~10 microteslas on the angrite parent body extending from 4564 to at least 4558 million years ago. Because the angrite paleomagnetic record extends beyond the expected lifetime of the early circumstellar disk, these paleofields were probably generated internally on the angrite parent body, possibly by an early dynamo in a rapidly formed metallic core.

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Blobrana · L

Magnetic fields record the early histories of planets
Meteorites that are among the oldest rocks ever found have provided new clues about the conditions that existed at the beginning of the solar system, solving a longstanding mystery and overturning some accepted ideas about the way planets form.
The ancient meteorites, like disk drives salvaged from an ancient computer, still contain magnetic records about the very early history of planets, according to research by MIT planetary scientist Benjamin P. Weiss.

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What Really Causes Falling Stars
Digital images of a "falling star" or a "shooting star" shows that it actually has nothing at all to do with a star! These amazing streaks of light you can sometimes see in the night sky are caused by tiny bits of dust and rock, in other words, meteoroids, falling into the Earth's atmosphere and burning up. The short-lived trail of light the burning meteoroid produces is called a meteor. If any part of the meteoroid survives burning up and actually hits the Earth, that remaining bit is then called a meteorite.

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Blobrana · L

The meteorite market has crashed to Earth, and will never reach the heights again.
In the late 1990s, during the great meteorite bubble, a gram of material from the Martian Zagami meteorite could go for $2,000. Today it fetches $200. The Christy's auction house sold a tenth of a gram of lunar rock for several hundred thousand dollars. Today lunar material fetches $400 a gram.
What happened? What always seems to happen in a bubble: Demand lead to speculative hoarding, which lead to oversupply, which lead to a crash.

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Blobrana · L

Danish scientists have developed a precise method to test for chromium isotopes in rocks and meteorites. The method will help to reveal more details about the evolution of the Solar System, they claim.
Supernovae explosions in the Solar System generate chromium-50, chromium-52 and chromium-53 isotopes. The amounts of these isotopes vary and are recorded in materials formed as a result of these explosions, such as meteorites, asteroids and planets.

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Meteorites could be source of world's precious metals
Rare and precious metals such as platinum, gold and iridium could have been brought to Earth by iron meteorites, according to new research by Dr Gerhard Schmidt of the University of Mainz in Germany.
Dr Mainz is due to present his results at the European Planetary Science Congress (EPSC), which is taking place in Münster, Germany, from 21 to 26 September.

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Blobrana · L

So-called shooting stars are small rocks burning up in the atmosphere.
When they are in space, they are called meteoroids, in the atmosphere they are called meteors, and once they have landed their new name is meteorite.
There are three main types of meteorite: stones, irons and a mixture of the two called stoney irons.
The irons are attracted by a magnet.

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