A friend of mine on Facebook recently posted a status that said simply “Gravity sucks,” which made me chuckle. Clearly it does. But what if it didn’t? I got to thinking about this a while ago for some reason. What if gravity was a repellent force rather than an attractive force?
The good news in this situation is that we’d all be able to visit space for free. The bad news is we wouldn’t have much of a choice in the matter. As it is, we have to be careful about falling. If you’re up on a roof, atop a waterfall, in a tree, etc…take a wrong step and you’ll plunge earthward at tremendous speed. If gravity was a repelling force, we’d have to be careful the other way – best to get yourself underneath a ledge or a branch or something attached to the earth lest you fly off into space. Imagine hanging from a traditional chin-up bar or tree branch, dangling over the infinite void. Hang on tight!
Clearly, this would make life pretty difficult, to put it mildly. It would completely prevent us (all life on Earth) from moving around, feeding, sleeping, mating…you know, the stuff life is made of. But the problem’s bigger than just life-on-Earth. If gravity was a repellent force, there wouldn’t even be an Earth. Attractive gravity is what holds Earth’s mass together in a cohesive lump. Repellent gravity would cause it to fly apart in all directions, an unfortunate state of affairs that would have prevented it from forming in the first place.
Even still, the problem with repellent gravity is bigger than Earth’s formation. It would prevent gas clouds from condensing to stars, prevent stars from clustering into galaxies, make orbits of all kinds impossible…the universe as we know it could not exist in the face of repellent gravity.
Gravity sucks. Good thing, too.
Fuggin Bizzy 
Mike – you’ve inadvertently stumbled upon the expansion theory of the universe. It turns out that in certain unique situations, it is believed that gravity IS repellent – and that helps explain some of the massive expansion that occurred immediately following the big bang. In a weird quantum nutshell, the jist of it is that THINGS didn’t expand with the big bang – SPACE ITSELF did via repulsive gravity. I refer you to the weighty but ultimately fascinating tome “The Fabric of the Cosmos” by Brian Greene. I’ll lend it to you when I finish it.