Re: What causes a falling star to fall?

First, we need to talk about some history. A long time ago (thousands of years ago), before people understood that there were lots of different kinds of things in the sky, like stars, planets, comets, asteroids, moons, meteors and stuff, they would look up in the sky and call every bright dot they saw a "star".

Of course, we know today that there are many different kinds of things in space besides stars. "Stars" are giant balls of burning gas that are millions of times larger than the Earth. Stars can be seen at night because they are glowing with their own light. Most other objects in space can only be seen because they are reflecting the light from a nearby star. the light from the Moon is just the reflected light from the Sun, for example. The Moon has no light source of it's own.

What people used to call "falling stars" are not stars at all. They are usually large rocks made of metal or ice that are just passing close to the Earth. If they pass closely enough, the gravity of the Earth pulls them into the Earth's atmosphere. We can't see these rocks (officially called "meteors") because they have no light source of their own. But when they start to fall through the Earth's atmosphere, the friction between the rock and the air begins to generate a LOT of heat, the same way your hands get warm by rubbing them together.

So much heat gets generated by friction that the outer layers of the meteor begin to glow. The meteor begins to burn and the light can be seen in our sky. It will look like a quick little stripe of color in the sky for a second or two.

Sometimes, the meteor completely burns up in the air and never reaches the ground. Sometimes, the meteor is so big that even after melting a little bit, it still makes it all the way to the surface of the Earth. When the meteors hit the Earth, they are now called "meteorites".

So, what causes a falling star to fall? The simple answer is: gravity; the same thing that makes everything else in the universe fall.

Thank you for your question.