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Planet Found in Double Star System
Daniel Dvorkin writes "CNN is reporting that a planet has been found in a double star system. I know, another extrasolar planet -- whoopee! But this one is different since it is in a double star system, and because given the size of the stars (the larger one is about 1.6 times as big as the Sun), the orbit (a little bigger than that of Mars), and the planet (somewhat bigger than Jupiter) it seems very possible that the planet might have a moon of roughly Earth's size and climate. I believe this is the first discovery that comes close to matching those criteria."
First of all I am not an astronomer (IANAA) nor am I a Starwars zealot. But I did see the movies and once in a library I flipped through a book on the Science of Starwars, or some such title. I have already seen a number of Starwars related comments, but I would like to give a few reasons why a minshara (I butchered that spelling, I am not a Trekkie either) class moon is unlikely from what I can remember based on that book.
A planet with a Jupiter like mass is probably a gas giant, like Endor, but if this gas giant is anything like Jupiter in our own solar system, then it has very strong magnetic belts. This would trap protons and electrons inside the field and create massive amounts of dangerous radiation.
It is possible that the second sun has an eliptical orbit with the primary sun at one of the foci. In this case the changing tidal forces may cause dramatic tectonic behavior, possibly strong enough to tear the moon apart, if the secondary sun ever gets close enough. A gas giant, being composed mostly of gas, would be able to withstand such tidal forces.
So life on such a moon might have to deal with some inhospitable conditions. Also, do not expect sunsets like on Tatoonie (or however that planet is spelled). The farther sun is so far away it would look like a bright star.
Another neat point is that, like our moon, any such moon would probably be locked into a position such that one side always faces the planet it orbits. Imagine if you were a primitive Ewok-like race living on the wrong side of the moon, you would never even know that you were orbiting a gas giant! (But think what a beautiful view of a gas giant you might have if you were on the other side....) In such a locked orbit, though, your notion of day and night would be ruled based on the time that it takes the moon to circle the planet and if you lived on the planet view side, imagine the amazing eclipses. (A gas giant may emit some light of its own....)
Darn it, now I have gotten myself daydreaming!
What sucks for the civilizaiton on that planet is that they may never learn to navigate spacecraft since the 3 body problem created by having 2 suns is inherently chaotic.
Pretty much everything in this comment is wrong. There are chaotic and non-chaotic solutions to the three-body problem. Sun, earth, moon is an example of the latter.
I suspect that if a planet was in an a chaotic orbit between two stars, then civilizations are not so likely, because climate variations could be extreme (e.g., Mars orbit one year, Venus orbit the next). But if a civilization did exist, then I can't see why they could not learn spacecraft navigation. Thr first challenge is to build rockets powerful enought to leave the planet - this is independent of the planet's orbit. Once they have gotten that far, I am sure the chaotic orbit wont stop them from sending the spacecraft to other planets.
Tor