Catch a falling star

"...and the chances of that happening," my friend said on the telephone, "are about the same as a meteorite falling from space and hitting me."

As a former astronomy student, I was quick to assure her that she couldn't possibly get hit by a meteorite. Not unless somebody threw one at her. Or perhaps dropped one on her from a hot-air balloon. But she has no reason to worry about either of those things because meteorites are rare finds, which means people don't tend to use them as slingshot ammo or as ballast for hot-air balloons. Rather, people tend to buy and sell meteorites, often for Serious Money.

Now pay attention, because this is the kind of little-known fact you can trot out whenever you want somebody to think you're clever. Work it into your next conversation and see if you don't get a free beverage out of it, at the very least:

You can't get hit by a meteorite that's falling from space because meteorites do not fall from space. I don't care what your grandfather's cousin Homer saw on that farm in West Virginia back in '49, that cow was not hit by a meteorite.

Is everybody confused? It's really quite simple, so stick with me.

Let's imagine that a hunk of stone with maybe a bit of iron and nickel in it gets knocked loose from an asteroid in a minor collision and begins hurtling toward Earth. That little traveler is called a meteoroid. When the meteoroid enters our atmosphere, the friction is going to heat things up and produce that whole streaky, sparkly, falling-star thing--and at that point our subject will be properly called a meteor. If this meteor doesn't completely vaporize (as most of them do), whatever's left will hit the ground. Now and only now has the little piece of space junk become a meteorite. In other words, a meteor that has hit the ground.

So you see, there's just no way a meteorite could ever fall from space and hit you on the head.

Watch out for those meteors, though.