Is having the Moon a curse?

Saturday, May 09, 2009

The Earth and the Moon to scale, including size and distance:
Sometimes though I wish this had been the scale between the two.

A planet the size of Earth having a moon as large as ours is a bit of an oddity, since Earth is simply not massive enough to make the capture of a body the size of the Moon a large possibility. The mass between a planet and its moons is generally extremely disproportionate, so when the masses of the two bodies are close enough that you could technically call it a binary system (as is the case with Pluto and Charon) there's usually a large possibility that the two were formed extremely close to each other, or perhaps that one formed out of another due to an impact a long time ago.

Since the Earth has a moon of this size we have had the benefit of an extremely interesting object in the sky at night. In contrast to every other object in the sky, the Moon goes through phases that anyone can see, and it has certainly been great PR for the idea of one day getting to space and perhaps reaching there. The argument could probably also be made that the progression towards becoming a spacefaring society is helped by having such objects in the sky, for the simple reason that it gives people an excuse to look up all the time, and the destination is right in front of our noses.

On the other hand, having the Moon may also be a bit of a curse, for a few simple reasons. Due to its large mass the Moon has a relatively high escape velocity, meaning that you need a rocket large enough to break the Earth's gravity to get there, and then you need another one to break the Moon's gravity on the way back. The Moon is also lacking in resources that we need, its dust is sharp, and days on the Moon last a whole month (14 days of day, 14 days of night), making it a very unnatural environment to live on.

At the same time it's closer to us than any other object, so it would seem to be the first destination of choice. The Moon is the only object that we can reach in a few days, but at the same time it's beyond the capabilities of your average small rocket to reach.

And the biggest problem could be this: the Moon makes LEO (low Earth orbit) look boring. Why fly around the Earth when you could be doing things on the Moon? It's an oddly tempting but at the same time oddly useless piece of real estate, and we can't ignore it.

Now imagine humanity on an Earth without the Moon. The only destinations for human exploration are: LEO, perhaps a quick trip to a near-Earth asteroid, and after that Venus, Mars, and Ceres. Everything else is much too far away. But Venus, Mars and Ceres still require months of time in that leaves LEO. In other words, without the Moon we would have made the only logical conclusion: humans must first colonize the area around Earth, and only the area around Earth. There would have been no rush to the Moon, but in its place there would have been a single goal that everyone could understand: first colonize space around Earth, develop the technology to go to other planets, and only then make the attempt to reach them.

Now let's imagine humanity on Earth with a Moon, but a different one. Mars' moon Phobos has an orbit of 10,000 km from the planet's surface and our moon is at a distance of 384,000 km, so let's choose something in between the two: a moon with a diameter of 1000 km (instead of 3400 km), so the mass is about 1/70th of our Moon now. Now it's safe to have it quite a bit closer to the Earth, so we'll put it 100,000 km away. All right, now we have an interesting object in the sky and lots of space to explore, but now the escape velocity is much lower, and it's extremely easy to reach. Even if this object has nothing we need in terms of resources it's still so easy to reach and return from that it would be the most logical destination to explore first.

But throw in a moon like ours and everything gets messed up. LEO first? But the Moon's right there, why not go? No wait, it doesn't have any resources so we should go to Mars. But Mars is too far away. What about Ceres? That's far away too and nobody knows about it. Okay, we'll go to the Moon. Nah, that still costs too much; only LEO is doable from a financial point of view. But LEO is boring, it's just going around the Earth over and over again.....

That's the endless debate between the proponents of LEO vs. Moon vs. Mars vs. other destinations, and it seems that the big culprit here is having the Moon + not having the technology necessary to make space travel easy and affordable. Once we improve to the point that both LEO and the Moon and other destinations become much easier to do (by easier I mean a large number of private companies are able to do it) this problem will recede and we can all laugh about it, but at the moment the issues brought about by having a moon like ours are quite annoying.

Personally I've always wished that we had two: the one we have now, plus one about 50,000 km away and a few times the mass of Phobos. Then we could have the best of both worlds - tides and interesting phases and words like lunacy, and one other destination much closer to us that we could already have a colony on the surface of.

Oh, and on a related note: there's a movie coming out next month called Moon as well.


  © Blogger templates Newspaper by 2008

Back to TOP