Before encountering the earth, a meteorite is technically a meteoroid - a fragment of rock in an elliptical orbit around the sun – traveling through space at about the same speed as the earth (30 km/sec.). When the orbital paths of the earth and the meteoroid chance to intersect, the meteoroid enters the earth's atmosphere and is rapidly slowed down due to friction with the air; great heat is generated by this friction and the meteoroid flares brightly and sometimes explodes. The flare itself, or "shooting star", is known as a meteor.
Provided the meteoroid does not burn up entirely, the rock (or fragments of it, if it exploded) falls to the surface of the earth, at this point having a speed no greater than any object falling to earth due to gravity. Enormous meteoroids can travel through the atmosphere without being slowed down, their great momentum overcoming the force of friction with the air, and strike the earth with such force as to cause an impact crater. Numerous craters on the earth's surface are known to have been caused by collisions of this sort, but these occurrences are rare.
The fall of a meteorite is quite a spectacle. Observers have reported coloured flashes in the sky that turn night to daylight, multiple explosions, and unusual crackling and thundering sounds both before and after the sighting. Near the actual fall, the sound of fragments breaking off the stone has been heard, as has the whistling of the falling stone and the thud of impact. On rare occasions, meteorite falls have caused damage or injury, but none of the meteorites recorded in Canada have done so.
When a meteorite is discovered, whether as a result of a meteor being seen in the sky or simply by accident (in which case it is referred to as a find, rather than a fall), it usually creates quite stir in the community. In the case of most Canadian meteorites, the finder has either reported the meteorite to the local museum or university, or announced it to the local press whose report was followed up by scientists who then obtained it for study. It is not uncommon, however, for meteorites to go unreported for years, the finder being either unaware of its celestial origin or more interested in its value as a living room curio than a scientific specimen. Iron meteorites make quite effective door- stops.
Once in the hands of scientists, the meteorite is weighed, measured, chemically analyzed, classified and named (the name coming from a nearby locality or physical feature). This information. along with the details of its recovery, are generally written up and published in scientific journals to alert the scientific community of the discovery. Following this original analysis, portions of the specimen may be removed and passed on to other institutions for additional study. As a result, fragments of one meteorite are often found in several collections around the world.
Over the years, meteorite finds have become more and more frequent. This is due most likely to an increasing awareness of their importance throughout an increasingly populated globe. As many as 50 meteorites a year now get reported, so a single occurrence is not nearly as newsworthy as it once was. Through the first half of this century. Scientific journals contained long descriptions of the sighting and discovery of an individual meteorite, but the greater frequency has dulled the novelty somewhat.
In recent years, the worlds meteorite count has more than doubled with the discovery of thousands of new meteorites on the Antarctic ice. These meteorites are not new falls: they appear to have fallen over hundreds of thousands of years and been preserved in the ice, then slowly carried with the ice currents to locations where the ice is eroded, leaving unusual concentrations of meteorites. Prior to the Antarctic discoveries, there were just over 2000 meteorites recorded in the world, but the Antarctic meteorites have increased those figures dramatically. Recent research suggests that a total of 500 to 1500 discrete meteorites have been found in the Antarctic from among the 10000 plus fragments recovered.
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