Meteors, Meteorites and Impacts

The three words in this category's name describe one object at three moments. A meteoroid is a small rock or grain in space. A meteor is the streak of light it makes when it hits the upper atmosphere at high speed. A meteorite is any piece that survives and lands on the ground. Most meteors come from grains smaller than a pea, and nearly all of them burn up high above the surface.

Meteor showers happen when Earth passes through the trail of dust that a comet left behind. The meteors in a shower seem to spread out from one spot in the sky, called the radiant, and the shower returns on about the same dates every year. The Perseids in August and the Geminids in December are two of the most reliable.

Meteorites are sorted into stony, iron and stony-iron types, and each type records a different chapter of the early Solar System. Real meteorites are rarer in backyards than most people hope. One guide here gives a short checklist for testing a suspicious rock at home and explains who can confirm a find.

Rarer, larger events get their own guides. In 1908 an object exploded over Tunguska in Siberia and flattened a vast area of forest. In 2013 another exploded over Chelyabinsk, Russia, and its shock wave broke windows across the region. Scientists use both events to understand how often objects of that size reach Earth. Impact craters, from Arizona's Meteor Crater to the buried Chicxulub crater, show what larger impacts did in the past.

These guides describe what happened and what agencies say, without predictions. To start, read the difference between a meteor, a meteoroid and a meteorite or learn how to watch a meteor shower.