By Alejandro Freixes, CCNN Head Writer
Is that a planet flying through space? Yes. Yes it is. Well, perhaps a bit smaller. On May 31, at about 2pm Pacific time (5pm Eastern), the asteroid named “1998 QE2” flew about 3.75 million miles from Earth. How far is that? It’s about 15 times the distance between the Earth and the moon. While that may seem very far, this is the closest the asteroid will come for the next 200 years! What’s even more interesting is that this asteroid has its own little moon, which is estimated to be 2,000 feet wide (a little less than half a mile).
Have you ever wondered, though, what the difference is between asteroids, comets, and meteors? So have I. First of all, comets and asteroids are leftovers from the earliest formation of our solar system about 4 billion years ago.
Comets are basically dirty snowballs made up of ice and rock, and when they get near the Sun, the icy center – called the comet’s “nucleus” – starts to burn away. This burning away can form their famous shiny tail of dust and gas. A few of them, once they’re all burned out, may even become asteroids. However, most asteroids don’t start off as a comet. Quite simply, an asteroid is a rocky body made up of metals – mostly nickel and iron – that orbits the Sun.
If a small piece of a comet or asteroid breaks off, it becomes a meteoroid. When a meteoroid enters the Earth’s atmosphere, it starts breaking up as a meteor and gives off the light that we like to point at and call “shooting stars.” If this shooting star (meteor) survives burning up through the Earth’s atmosphere and actually lands on the Earth’s surface, it’s now called a meteorite.
So, ready for a quick review? Comets have ice whereas asteroids just have rock. When a piece breaks off of either one, it’s now a meteoroid that becomes a meteor if it enters Earth’s atmosphere and a meteorite if it survives the landing.
Images courtesy of NASA.