Meteorite Impacts as a Threat to Civilization
Imagine that while you’re on a peaceful Sunday afternoon stroll with your family, a large dark gray ball comes out of nowhere, just missing the head of your small child, shakes the earth, and produces a large crater in the ground a few feet ahead of you. This ball wasn’t from the young boys playing baseball across the street, and it wasn’t an acorn from the tree overhead. This ashen ball was a meteorite falling from the sky.
A meteorite is a particle from space, large enough to enter the earth’s atmosphere, and potentially cause damage to the surface of the earth, a house, or a car. Although almost getting struck by a meteorite while outside on a walk is a very rare occurrence, a collision with a meteorite can be fatal. Scientists have never encountered a fatality due to a meteorite, but several deformations in the surface of the earth have been linked to meteorite collisions.
A meteorite comes from an asteroid or is a chip off of a moon or other planet. Many times a planet or other solar object is heated beyond capacity and, consequently, explodes thrusting many fragments into the universe. Some of these fragments are large enough to successfully enter the earth’s atmosphere and hit the surface at amazing speeds. Most meteorites are blasted apart by fire while entering the earth’s atmosphere.
Meteorites are often dark gray or black because of their fiery descent. They are very rough on the outside. They are often identified by scientists by their composition. A meteorite has a very rare element, iridium, present in its makeup. This makes meteorites easy to decipher from surface rocks because all of the earth’s iridium sank to the core many years ago. Many meteorites are filled with metals that give them a rich magnetic power. Meteorites also contain carbons.
Meteorite collision has been responsible for many craters in the surface of the earth, and it continues to shape the land. As for meteorite impact becoming a threat to civilization, it is highly unlikely.
The Torino Scale is a device used to measure the predicted threat of a meteorite colliding with the earth. Very few meteorite impacts large enough to threaten civilization are rated over zero on the Torino Scale. This means that it is unlikely that a very large meteorite will strike the earth hard enough to cause such damage. It is improbable that a meteorite will do much damage, and any large meteorite able to cause such damage will probably not enter the earth’s atmosphere in tact.
The Torino Scale rates potential collisions from zero to ten. A “zero” rating is given to those objects that have the least likelihood of entering the earth’s atmosphere and doing any damage. A “ten” rating is given to those objects that will certainly collide with the earth and have the ability to cause devastating damages. Most objects rated one or higher usually change paths, and the rating is changed in time.
Although it is unlikely, the next time you’re out for a Sunday afternoon stroll and are almost nailed by a flying ball, pick it up. Check it out. You may have discovered a meteorite; a rock from the world beyond that was, for a long time, a complete mystery to us.
1. Bennett, Donahue, Schneider, Voit. The Cosmic Perspective. Addison-Wesley