It seems like every few weeks, the tabloids tell us we’re all going to die. The culprit of this frequent apocalypse: Asteroids.
So, let’s talk about asteroids for a bit. The word “asteroid” means “star-like,” although asteroids don’t have anything to do with stars. An asteroid is a small celestial body, basically a chunk of rock, metal, or both. Most asteroids hang out in the Asteroid Belt, which is located between the orbits of Mars and Jupiter. The largest asteroid is a dwarf planet named Ceres.
However, not all asteroids hang out in the belt (which, by the way, does not appear to be a former planet which exploded, but is just a place where the various interplaying gravitic forces from the Sun and the gas giants tend to put debris). Some asteroids wander around. And a subset of those are what we call “Earth-crosser” asteroids and “Near-Earth asteroids.” Those are the ones we’re worried about.
What are Near-Earth Asteroids?
These asteroids cross Earth’s orbit while on their own route around the sun. Which means that if things go wrong, they may collide with the Earth. And this actually happens fairly often. 64 million years ago, a huge one hit and wrecked the Earth’s ecosystem. If it hadn’t happened, then this article might be being typed by a descendant of velociraptors! Okay, so that’s pure speculation, but the point is: We have a reason to worry about asteroids.
But how much of a reason do we have? Because I just said it happens fairly regularly and we’re all still here.
Well, here’s the thing. Asteroids vary in size, a lot. Our best estimate of the size of the rock which destroyed the dinosaurs was that it was somewhere between 7 and 8 miles wide. That would destroy our civilization and possibly our species, but life would rebound, as it did before. Additionally, most of the near-earth objects aren’t classed as asteroids, but as meteoroids. Of the 19,470 NEOs we have discovered and charterd, only 1,955 are classed as “potentially hazardous asteroids.” This means there’s a non-zero chance they will hit us, and that…