The crater is nearly 1,300 meters or one mile across and about 180 meters or 600 feet deep. One of the best examples of a large crater carved out by a meteorite is Meteor Crater in Arizona. The depth of the hole depends on the softness of the ground. The size of the hole will depend on the size, weight and speed of the meteorite. What happens when it hits?Ī meteorite will usually leave a hole, or crater, in the ground. The final speed of a meteorite just before touching down may be only 1.5 kilometers per second or less. The air around us can do much to slow down a moving object. This effect is noticed when riding a bicycle into a strong wind. If a meteorite comes from the opposite direction that the Earth is moving, the overall relative velocity can be as high as 73 km/s.Īs a meteorite gets closer to the Earth's surface, the speed of entry is rapidly reduced by wind resistance. The Earth moves around the sun at about 30 kilometers per second. The intrinsic velocities of Earth and meteorite can sum, so speed of entry depends greatly on the direction from which they came. Meteorites enter the Earth's atmosphere at a speed between 11 and 40 kilometers per second. Meteorites have also been thought to be messengers from the gods. It has been said that the Chinese buried meteorites shortly after they were recovered so that their crops would not be ruined.
There were also superstitions about meteorites. Others used them to make nails and anvils. People have used iron meteorites to make weapons, such as swords and knives. Other ancient societies, Roman, Egyptian, Chinese and Japanese, also recorded similar meteorite events. However, a large carbonaceous chondrite, the Allende meteorite, which shattered when it landed in Mexico in 1969, has been a remarkable source of so-called presolar grains, which appear to have originated in the outer shells of stars which exploded before the formation of the Sun! Space invaders?Īs far back as the year 476 B.C., ancient Greeks recorded that 'a stone the size of a chariot' fell from the sky. Most meteorites come from material which condensed or crystallized at the birth of the Solar System. The last three percent consists of the stony-irons, which are half metallic and half silicate. They represent about 28 percent of known meteorites because they are both tough and distinctive, they are well represented in collections, yet are only 7 percent of observed falls. Irons are metallic meteorites made chiefly of iron and nickel. The stony meteorites are the most common group, forming about 69 percent of all known meteorites (including all 'falls', seen to fall to Earth, and 'finds', picked up at a later date.) Commonly about a millimeter in diameter, they are formed from an aggregate of the silicates olivine and pyroxene.
Stones (stony meteorites) are silica rich a large proportion of them contain chondrules, sphere-shaped material not found on Earth. There are three main groups of meteorites, distinguished by their different composition. The metal in meteorites consists mostly of iron with smaller amounts of nickel and cobalt.
Only rarely is it present in Earth rocks. One big difference between meteorites and Earth rocks that you can usually recognize is that nearly all meteorites contain metal. It sometimes requires special equipment, such as powerful microscopes, to do so. It is not always easy to distinguish meteorites from Earth rocks. And since the time that humans have occupied the Earth, many hundreds have been seen to fall to the ground and were later recovered. Since the time the Earth was formed, many millions of meteorites have landed on its surface. The size of a meteorite may range anywhere from that of a small pebble to that of a gigantic boulder. It is usually in the shape of a stone or large rock. What exactly is a meteorite?Ī meteorite is a body of solid material that has fallen to Earth from space. Generally, a close and careful inspection is required to show that a meteorite is different from any rock that was formed on Earth. But it is not likely that you would have taken notice because most meteorites, upon first glance, look like ordinary Earth rocks. If you have ever walked through an open field, down a dirt road, or in the mountains, chances are that you stepped over a meteorite.