The Dilemma: Something from the heavens just crushed your boss, and you’re pretty sure it wasn’t a foul ball.

People You Can Impress: astronomers or just folks wishing on “shooting stars”

The Quick Trick: Oids are outside the atmosphere, ites are inside it, and meteors are in between.

The Explanation:
Say you’re a bit of interplanetary dust or debris trucking through the vacuum of space, minding your own business. You’re not very big. Certainly not big enough to be called an asteroid. In fact, you might just be a speck of dust or even smaller. Congrats! You’re a meteoroid!

But say, for example, a bright blue planet suddenly gets in your way and sucks you in, and before you know it you’re streaking through an atmosphere so fast that you ablate (fancy way to say “vaporize”) and let off a bright streak of light. You are now officially a meteor.

Now, on the other hand, if you started out big enough, then enough of you will emerge from this furnace o’ friction to hit the ground in some farmer’s field, making you a meteorite. Mazel tov! Of course, we should specify here: If you’re made of rock, you’re called a chondrite. Mostly metal? You’re an iron meteorite. A little of both? Say, a rock wrapped in metal? You are hereby dubbed a pallasite.

Believe it or not, about 25 million meteoroids hit Earth’s atmosphere every day. And while most of them burn away to nothing, sometimes the Earth’s orbit will take them through a messy patch of interplanetary junk, like the orbit of a dead comet that’s broken into millions of meteoroids. In such a case, the Earth’s gravity can hoover up these particles by the millions—creating meteor showers. A huge shower emanates from the direction of the constellation Perseus every August, for instance, creating an event that’s widely publicized and not to be missed.

So What’s an Asteroid?
Just as meteoroids are too small to be called asteroids, asteroids are too small to be called planets. Most asteroids that have been discovered (there are now well over 100,000) range from about 10 kilometers to 100 kilometers in diameter and are found in a belt between Mars and Jupiter. In fact, scientists believe that this asteroid belt was a nascent planet that, bullied by Jupiter’s immense gravity, never quite got it together. Asteroids are grouped into a number of families based on their orbits. Those whose orbits cross the Earth’s orbits are called Apollo asteroids. Earth crossing is not a good thing, however. If an asteroid just 1 kilometer across were to hit the Earth, we wouldn’t get a pretty light show. We’d get a jolt equivalent to a 20-megaton nuclear blast, leaving a crater with a diameter equal to the length of Manhattan. That kind of jolt is survivable—if you’re a character in the movie Deep Impact. If you’re a human on earth, it stirs up a bit more trouble.