A LAYMAN’S SCIENCE OF HEAVENLY BODIES:
A METEOROID is a small rock or particle of debris in our solar system. They range in size from dust to the size of a pebble and even to 10 meters in diameter. Objects larger than that are usually referred to as asteroids.
A meteoroid that burns up as it passes through the Earth’s atmosphere is known as a METEOR. What we consider as a ‘shooting star’ is actually a meteor. The root word meteor comes from the Greek meteōros, meaning “suspended in the air”. Millions of meteors hang to the Earth’s atmosphere daily.
A METEORITE ,on the other hand, is a portion of a meteoroid or asteroid that survives its passage through the earth’s atmosphere and hits the ground without being destroyed.
What puzzled me was that if, first comes the meteoroid ,then the meteor and after that the meteorite then why was this crater called the meteor crater and not the meteorite crater! While I was wondering about all this Samit, my hubby ,called me to see the movie which was about to start in a few minutes .
People were already seated inside so when I entered I couldn’t see anything but the wide screen in front of me which was by that time showing a huge meteor hurling towards earth at supersonic speed .With this ,went on a detailed explanation on meteors and craters in general and specifications on this particular meteor crater.
From the movie what we came to know about an IMPACT CRATER is that it’s somewhat like a scar on the earth’s surface left by the hypervelocity crash of a meteorite. It’s different from a volcanic crater, which results from an explosion or collapse from within the earth. Impact craters typically have raised rims and floors that are lower in elevation than the surrounding terrain.
Craters can be as young as the Sikhote-Alin craters in Russia, whose creation was witnessed in 1947;or they can be more than two billion years old like the Vredefort or Chesapeake ,though most are less than 500 million years old because geological processes tend to obliterate older craters .They are also mostly found in the stable interior regions of continents for the obvious reason that the ones in the middle of the ocean would be difficult to identify.
Impact craters range from small, simple, bowl-shaped depressions- like the Sikhote-Alin craters in Russia- which were more a meteorite shower in which 106 craters and many pieces of meteorites were found in the forest- to large, complex, multi-ringed impact basins like the Vredefort crater in South Africa ,the largest verified impact crater on Earth, which spreads to almost more than 300 km across land and consists of three towns ,rivers , lakes and forests. Few undersea craters like Chesapeake Bay have also been discovered but these craters are really difficult to label as a tourist attraction because of their size and location under water.