Friday, August 10, 2007

How many suns?

Guess what? One sun per solar system is not the norm. Apparently, its about 50/50 between one sun, and a binary system. Some systems even have more than two suns in them!

Is that strange? Probably not. Virtually all solar systems that have been discovered to have planets, have gas giants in them. We have 4 gas giants in our system; Jupiter, Saturn, Uranus, and Neptune. Jupiter, our biggest planet, is also classified as a Brown Giant, or a Glowing Planet (meaning that the planet kicks out energy from its own internal fusion). It has been estimated that if Jupiter was 5 times the mass, it would probably combust under its own mass and become a star. So Brown Giants are stars that have failed in ignite because they are not fat enough :)

A Gas Giant that is 70% the size of Jupiter has been recently discovered orbiting a sun in the Hercules system. But it is orbiting so close to the star that its atmosphere is being stripped off. In who knows how millions of years, it will have been blown away to nothing!

So its no wonder that there are so many suns out there. We could easily have ended up with a sky that would not look out of place in a Star Wars movie. In fact, the excellent movie 2010 is actually about Jupiter being turned into a sun by mysterious aliens. The movie ends with one of my favourite lines ever "All these worlds are yours, except Europa. Use them together in peace". I would sure enjoy looking at that sky!

So the mind boggles when you realise they have discovered a system with four suns in it! A double binary system. This is an artists impression of it. I wonder what that sky would look like if you could visit a planet in that system and look up?


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