A couple of people were nice enough to suggest I check out this recent movie. I did and of course I’d like to share it with you as well. Space geekout!
(Protip: go HD)
So what are we seeing here? We see the position of known asteroids in our Solar System from 1980 – 2010 in extreme time-lapse. But we only see the asteroids that were know at that time. As new asteroids flash up as they are being discovered. As we approach 2010 it gets quite crowded. There are a couple of cool things to observe.
I like how you can see exactly the search pattern for asteroids. Asteroids are mostly discovered looking away from the sun. This is when asteroid will be lit like a full moon so it will be easier to spot. That’s why the flashes of newly found asteroids follow the earth like a shadow. From time to time there are larger groups of flashes. These are concentrated survey programs.
The video also shows a weird aspect of space exploration. We are used to geographical mapping. We imagine it somewhat like the the exploration in games like Civilization. We start out with “blank spots” on a map, then we actually travel there to see what’s there and to gradually fill in the blanks. Space doesn’t work this way. Space is generally blank and we never go anywhere. We just observe and gradually find more and more objects. The objects we discover first are the ones that are the easiest to spot. Those are mostly the biggest, brightest and nearest objects. We can never really be sure if the “blanks spots” on our maps of space have been filled because there is always the possibility of an object that is just difficult to spot.
Many people’s reaction to he video is “gosh, there are so many asteroids, we are doomed”. Well yes and no. Fist of all, the size of the asteroids and the size of the planets is obviously greatly exaggerated. Even Earth itself would appear as just a tiny, tiny fraction of a fraction of a pixel in this resolution. There are a lot of asteroids and they can be large but the space depicted is incredibly vast. Imagine tiny specs of dust suspended in a aircraft hangar. Also, keep in mind that this is 2D and space is 3D. Many of the Asteroids move up and down as they circle the Sun. So even if an asteroid would appear to “hit” the earth on this video, it could be moving hundreds of thousands of kilometers above or below it. And in the end, many asteroids are just too small to do any damage and would end up as shooting stars. In fact, two asteroids passed Earth awfully close just recently. There were even closer than the Moon! But nobody cared because they were tiny and didn’t even hit us.
*Cue the disappointed “Oooooh!” of a golf tournament audience*
That being said astronomers agree that it is only a matter of time until we are going to get hit by something big. It might be tomorrow. But if you take it rationally, it is more likely that we won’t be around when that happens. Still, it would be a very good idea to invest in a lot more in a solid sky watch program. As you can see there are still a lot of undiscovered asteroids. To give you an idea how underfunded those guys are: humans invested more in the movie Armageddon than in survey programs that look for real asteroids.
