Most meteorites originate in the asteroid belt, situated between the orbits of Mars and Jupiter. At least 1 million asteroids reside in this belt with diameters greater than 0.6 mile (1 km), 1,000 with diameters greater than 18 miles (30 km), and 200 with diameters greater than 60 miles (100 km). Asteroids and meteoroids are distinguished only by their size, asteroids being greater than 328 feet (100 m) in diameter. Meteoroids are referred to as meteors only after they enter the Earth's atmosphere, and as meteorites after they land on the surface. These are thought to be either remnants of a small planet that was destroyed by a large impact event, or perhaps fragments of rocky material that failed to coalesce into a planet, probably due to the gravitational effects of the nearby massive planet of Jupiter. Most scientists favor the second hypothesis, but recognize that collisions between asteroids have fragmented a large body to expose a planetlike core and mantle now preserved in the asteroid belt.
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Preparing for Armageddon, Natural Disasters, Nuclear Strikes, the Zombie Apocalypse, and Every Other Threat to Human Life on Earth. Most of us have thought about how we would handle various types of scenarios that could signal the end of the world. There are plenty of movies on the subject, psychological papers, and even survivalists that are part of reality TV shows. Perhaps you have had dreams about being one of the few left and what you would do in order to survive.