Meteoritics –The Branch of Astronomy Studying Meteors, Meteorites and Meteoroids

Meteoritics, a comparatively new field in science, studies meteoroids, meteors, and meteorites. A successful meteoriticist needs to have a grasp on a number of subjects like astronomy, astrophysics, biology, chemistry, mineralogy, metallurgy, petrology and geology. This field has seen a vast growth in the last three or four decades.

In the early centuries both layman and scientists approached meteorites with reverence. Ancient civilizations worshipped the meteorites. For example, the ancient Romans worshipped a meteorite called the Phrygian, the fall of it is recorded in 2000 B.C. The oldest historical record documenting a meteorite is for an L-chondrite, which hit Earth in 861 A.D. and is preserved in Nogata, Japan. Another chondrite of historical note is still preserved in the Ensisheim Town Hall, in Ensisheim, France, which fell on 1492 . Even though this meteorite was preserved, scientists had not conducted a study because of the superstitions which surrounded the meteorite. A marked change in the approach of scientists occurred towards the end of 18 ^th century. It was Ernest Friedrich Chladni, who first proposed a scientific explanation for the meteorites. He published his findings in 1794. Even though his work was not acknowledged by his contemporaries, he is now considered as the Father of Meteoritics.

On April 26, 1803, L’Aigle, France recorded a brilliant meteor shower. Jean-Baptist Biot of the French Academy of Science studied in detail the L-chondrites collected from this shower. He underlined Chladni’s findings that meteorites are materials from space. Thus slowly, the myths surrounding the meteorites began to be dispelled.

Today, with the help of modern technology, Meteoriticists are able to classify meteorites into different groups according to their composition.

• Chondrites: They are the most common meteorite. They are rich in chondrules, which contain silicate minerals.
• Achondrites: They don't contain chondrules and are believed to be once part of Mars or the Moon.
• Iron meteorites: These meteorites are rich in alloys of iron and nickel and are similar to core of the Earth.
• Stony-iron meteorites: These meteorites contain both iron and nickel alloy and non-metallic compounds which resemble the mantle of the Earth.

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Meteorites are a great source of information. They are the visitors from otherwise inaccessible places in our Solar System. They shed light onto the composition of the celestial object from which they were formed. Their study provides information on how and when these meteorites are formed and give scientists an opportunity to study the process, and the materials of the early solar nebula. They present a source to study pre-biotic chemistry, which prevailed in the early solar system and to correctly deduce the age of the solar system.

Meteorites are rich in carbon, which mainly appear as polycyclic aromatic hydrocarbons (PAH), which are stable and the most common carbon compound in the space. But contrary to the normal PAH, those found in meteorites contain an extra oxygen or hydrogen. This abnormal PAH called quinones, formed by a number of chemical reactions, is believed to have laid the foundation for life on Earth.

The meteorites from the Mars and the Moon are studied to learn about the environmental and chemical nature of these celestial bodies.

The Antarctic is rich with meteorites. In 1991, a US meteorite search expedition in the Antarctic unearthed a meteorite, which is about 4.5 million years old. Since it was formed at a time when the solar system is believed to be forming, it is expected to provide information on the birth of the solar system. From the analysis of this meteorite, scientists concluded that gas-solid condensation within the solar nebula played a major role in its formation.

Even though extensive studies are conducted in the field of Meteoritics, there are a wealth of questions yet unanswered.

Sources:

http://www.meteoritemarket.com/type.htm

http://www.meteorlab.com/METEORLAB2001dev/metics.htm

http://www.sciencedaily.com /releases/2008/09/080925102706.htm

http://www.spacedaily.com/news/early-sol-00a.html

Image:

http://en.wikipedia.org/wiki/File:Canyon-diablo-meteorite.jpg