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Posts Tagged ‘meteorites’

Curiosity Confirms Origins Of Martian Meteorites

October 16, 2013 Leave a comment

Earth’s most eminent emissary to Mars has just proven that those rare Martian visitors that sometimes drop in on Earth — a.k.a. Martian meteorites — really are from the Red Planet. A key new measurement of Mars’ atmosphere by NASA’s Curiosity rover provides the most definitive evidence yet of the origins of Mars meteorites while at the same time providing a way to rule out Martian origins of other meteorites.

The new measurement is a high-precision count of two forms of argon gas—Argon-36 and Argon-38–accomplished by the Sample Analysis at Mars (SAM) instrument on Curiosity. These lighter and heavier forms, or isotopes, of argon exist naturally throughout the solar system. But on Mars the ratio of light to heavy argon is skewed because a lot of that planet’s original atmosphere was lost to space, with the lighter form of argon being taken away more readily because it rises to the top of the atmosphere more easily and requires less energy to escape. That’s left the Martian atmosphere relatively enriched in the heavier Argon-38.

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Solar System’s Youth Gives Clues To Planet Search


Disk isotopes modeling results. Image courtesy of Alan Boss

Disk isotopes modeling results. Image courtesy of Alan Boss

Comets and meteorites contain clues to our solar system’s earliest days. But some of the findings are puzzle pieces that don’t seem to fit well together. A new set of theoretical models from Carnegie’s Alan Boss shows how an outburst event in the Sun’s formative years could explain some of this disparate evidence. His work could have implications for the hunt for habitable planets outside of our solar system. It is published by The Astrophysical Journal.

One way to study the solar system’s formative period is to look for samples of small crystalline particles that were formed at high temperatures but now exist in icy comets. Another is to analyze the traces of isotopes—versions of elements with the same number of protons, but a different number of neutrons—found in primitive meteorites. These isotopes decay and turn into different, so-called daughter, elements. The initial abundances of these isotopes tell researchers where the isotopes may have come from, and can give clues as to how they traveled around the early solar system.

Stars are surrounded by disks of rotating gas during the early stages of their lives. Observations of young stars that still have these gas disks demonstrate that sun-like stars undergo periodic bursts, lasting about 100 years each, during which mass is transferred from the disk to the young star.

Full Story: https://carnegiescience.edu/news/solar_system%E2%80%99s_youth_gives_clues_planet_search

Grains Of Sand From Ancient Supernova Found In Meteorites


Credit: NASA/JPL-Caltech/ O. Krause (Steward Observatory

Credit: NASA/JPL-Caltech/ O. Krause (Steward Observatory

It’s a bit like learning the secrets of the family that lived in your house in the 1800s by examining dust particles they left behind in cracks in the floorboards.

By looking at specks of dust carried to earth in meteorites, scientists are able to study stars that winked out of existence long before our solar system formed. This technique for studying the stars – sometimes called astronomy in the lab — gives scientists information that cannot be obtained by the traditional techniques of astronomy, such as telescope observations or computer modeling.

Now scientists working at Washington University in St. Louis with support from the McDonnell Center for the Space Sciences, have discovered two tiny grains of silica (SiO2; the most common constituent of sand) in primitive meteorites. This discovery is surprising because silica is not one of the minerals expected to condense in stellar atmospheres — in fact, it has been called ‘a mythical condensate.’

Because the grains, which were found in meteorites from two different bodies of origin, have spookily similar isotopic compositions, the scientists speculate in the May 1 issue of Astrophysical Journal Letters, that they may have come from a single supernova, perhaps even the one whose explosion is thought to have triggered the formation of the solar system.

Full Story: https://news.wustl.edu/news/Pages/25306.aspx

A Meteorite Mystery: First Meteorite From Mercury Found?


Image Credit: Stefan Ralew

Image Credit: Stefan Ralew

Could this stone be the first meteorite from Mercury ever found? WUSTL’s meteorite expert sifts the evidence.

Early in 2012, someone in Southern Morocco picked up 35 greenish stones, including the one shown. Purchased by a dealer in Erfoud, Morocco, it was then resold to Stefan Ralew, a meteorite collector from Berlin.

The dealer was demanding a high price, and Ralew may have hesitated. But the wrinkled glassy coating on one face of the rock was clearly a fusion crust, a kind of glaze that forms when a meteorite is heated as it passes through the atmosphere.

Looking at other faces he would have recognized it as a type of meteorite called an achondrite, says Randy Korotev, WUSTL’s meteorite expert. That meant it was an exceptional stone.

Full Story: http://news.wustl.edu/news/Pages/25222.aspx

Mars Missions May Learn From Meteor


Scientists have tried to find out how the planet’s environment came to contain methane gas, which contains carbon – a substance found in all living things.

They found that meteorites, which continually bombard the surface of Mars, contain enough carbon compounds to generate methane when they are exposed to sunlight.

Scientists planning future missions to Mars could use the findings to fine-tune their experiments, potentially making their trips more valuable.

Full Story: http://www.ed.ac.uk/news/all-news/300512-mars

NASA Detects Metabolic Precursors in Meteorite Dust

August 24, 2011 Leave a comment

NASA scientists have found organic compounds associated with cellular respiration in carbonaceous meteorites, and simulated space-like conditions in the laboratory to determine how the compounds could have formed in deep space billions of years ago.

Full Story: http://www.nasa.gov/centers/ames/news/releases/2011/11-65AR.html