Meteorites

Pieces that survive the journey and
hit the ground are called meteorites.

Meteorites
Little chunks of rock and debris in space are called meteoroids – they become meteors or shooting stars, when they fall through a planet’s atmosphere – leaving a bright trail as they are heated to glow by the friction of the atmosphere (photo).

  • meteorites are small – less than about 1,000 tonnes, solid objects from space that have impacted the surface of a planet or moon.
  • the largest known meteorite weights more than 60 tonnes and is still lying where it fells at Hoba West in Namibia, Africa. (Photo: found it / today)
  • discovered in Greenland by the famous explorer Robert Peary in 1897 – the largest meteorite on public display weight 34 tonnes; nicknamed `Ahnighito` – Peary sold the pieces for $40,000 to the American Museum of Natural History in New York City where they are still on display.
  • meteorites found on Earth can be divided into three main categories – popularly known as irons, stones and stony-irons.
  • irons, which used to be called siderites – are composed almost entirely of the metals iron and nickel (or alloy of the two) and their found outer surface is often covered with rust.
  • stones, which used to be called aerolites – are composed of silicate minerals such as pyroxene, olivine and feldspar together with a small amount of nickel or iron.
  • two sub types of stony meteorites – chondrules which often have rounded appearance and a structure made up of tiny rock spheres known as chondrules and chondrites, which usually have a jagged appearance and do not contain chondrules.
  • stony-irons which used to be called siderolites – are composed of silicate minerals and nickel-iron in roughly equal proportions.  (Stony-irons are very rare and only about 4% of meteorites fall in this category.
  • Tektites are small, rounded objects – made of silica glass;previously thought to be meteorites, it is now accepted that tektites are produced by the impact of as asteroid striking Earth.
  • best places to find meteorites are Antarctica because there has been so little human activity there! (photo)

 

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