Alan Hills (ALH) 84001: Meteorite

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    In Context 

    • The Recent study explains the existence of organic compounds on the surface of Meteorite ALH 84001.

    About Alan Hills (ALH) 84001

    • It was found during a snowmobile ride in December 1984, in the Far Western Icefield of Allan Hills in Antarctica by a US meteorite hunting expedition. At the time of its discovery, it was recognised as the most unusual rock collected.
      • At that time, it was described as shaped like a rounded brick or a large potato, about 6 inches long by 4 inches by 3 inches, and was partly covered with black glass (like it was dipped in tar). 
        • The glass, called fusion crust, forms on all meteorites when they burn through the Earth’s atmosphere. 
        • ALH 84001 looked green inside, which excited the expedition.
    • In 1996 NASA scientists who carried out microscopic and chemical analyses on ALH84001 touched off a controversy by suggesting that the carbonates in the meteorite had been produced by Martian microorganisms
    • For about four decades scientists have debated if the organic compounds found on the surface of the meteorite called (ALH) 84001 were proof of ancient, primitive life on Mars. 
      • These debates also included the possibilities that the compounds could have come from volcanic activity, impact events on Mars or hydrological exposure.

    Key Highlights of a recent study 

    • The study posits that the organic compounds found in the meteorite were a result of the interactions between water and rocks that occurred on Mars. These interactions were similar to those that happen on Earth.
    • These kinds of non-biological, geological reactions are responsible for a pool of organic carbon compounds from which life could have evolved and represent a background signal that must be taken into consideration when searching for evidence of past life on Mars.
    • It noted that even though no human has ever stepped on Mars and no rocks have as yet been analysed.
    • It can be said with certainty that the meteorite did come from the Red planet because of the presence of traces of certain gases that are just like the Martian atmosphere.

    Relevance of studying 

    • Scientists are interested in studying meteorites as examining them offers clues about the beginning of the solar system and maybe even the Earth. 
    • Space agencies have launched specific missions to asteroids to be able to study them.
      •  One such example is NASA’s OSIRIS-REx mission launched in 2018 with the aim of reaching asteroid Bennu and getting back a sample from the ancient asteroid.

    Meteorite

    • Meteoroids are objects in space that range in size from dust grains to small asteroids.
    • Also known as “space rocks”
    • When meteoroids enter the Earth’s atmosphere, they are called meteors. 
    • But if a meteoroid enters the Earth’s atmosphere and hits the ground, it is called a meteorite.

    Source:IE