I Didn’t Know That

Q: How often do meteors fall to the Earth?

A: About 25 meteorites weighing more than a fifth of a pound fall on California (or an area of equal size) each year, according to planetary scientist William Bottke of Caltech. Three or four of them weigh about 2 pounds and are the size of a fist. Very few are found.

One common class of meteor is called a “fireball” because of the streaming path of light it leaves when matter on its surface is boiled away by the heat of entry into Earth’s atmosphere. Fireballs decelerate from a speed of about 60,000 mph to about 200 mph during this period, often slowing enough at the end so that they literally fall straight to the ground.