Okay, that title is unnecessarily crude, but fuck it. What follows is a video showing the number of asteroids that have been discovered since 1980.
Can you figure out which little dot is the earth? Here’s a hint: it’s the one going around the sun (err…which one is the sun, I wonder).
One thing you might notice is the sudden burst of discoveries at right angles to the earth right near the end of the video. I’m guessing those are discoveries made by the WISE satellite, which launched in December of 2009. The WISE satellite (Wide-field Infrared Survey Explorer) is an infrared survey satellite that is always pointed 90 degress from the sun and earth…exactly where all those asteroids are being found.
One thing that might be making you a bit nervous is the sheer number of asteroids that we can see by the end. With so many of ’em, the chances of being hit by one must be really high, right? Well, not really. Here, I’ll let my very close and personal friend whom I’ve never met, Phil Plait, explain why that is (from this post at his blog Bad Astronomy):
The distance between Mars and Jupiter is a bit roomier than depicted in the video. Remember, Mars is about 220 million km (130 million miles) from the Sun, and Jupiter is about 800 million km (480 million miles). That’s a whole lot of real estate: almost 2 quintillion square kilometers (670 quadrillion square miles)! Written out, that’s 2,000,000,000,000,000,000 square kilometers.
Yeah, a whole lot of real estate.
And that assumes those asteroids all lie in the same plane. In fact, many of their orbits are tilted, so we’re really dealing with volume. Even allowing that they may move above or below the plane of the solar system the paltry amount of a million kilometers, that means there’s really 2 septillion cubic kilometers: 2,000,000,000,000,000,000,000,000 cubic km! The volume of the Earth is only about a trillion cubic kilometers, so we’re talking a volume of space that could fit a trillion Earths in it!
Methinks we need not worry quite so much.