Saturday, June 02, 2007

Design Your Own Habitable Planet

Astroventure is a NASA site that lets you design your own habitable planet, taking into account geology, atmospheric science and, of course, biology. Like all such simulations, it makes a bunch of assumptions about the minimum requirements for life. All we really know about is life on Earth - we may not be able to imagine what truly alien life might require.

Since we haven't actually visited any other star systems, we are still trying to figure out what the conditions on planets outside our solar system might be like. For example it's been thought that planets orbiting red dwarf stars would be bombarded with lethal doses of ultraviolet radiation and particles. However, Edward Guinan of Villanova University and his colleagues recently published a paper speculating that such planets might be more hospitable than originally thought. As the news@nature.com article reports:
Periodic solar flares could still deliver enough radiation to sterilize animals, says Guinan. Plus, 'tidal locking', which forces a moon or planet's rotation to synch with that of the body it orbits, would probably leave one side in continual, searing light.

But, Guinan says, winds could circulate warm air to the night side, keeping it as warm as a summer night in Hawaii.

And red dwarfs are very stable, so the planet could remain habitable for billions of years, unlike our Sun, which will support life only for another 1.5 billion years.
This is exciting speculation, since red dwarf stars are much more common than yellow stars like our Sun. There may be a much greater likelihood of life in our galaxy than previously calculated. NASA is going to have to update its simulations . . .

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