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Sunday, August 10, 2008

Solar System Appears to be Unique in the Galaxy

click the galaxy picture for a larger image

A new study has shown that the configuration of our Solar System appears to be unique in the Milky Way galaxy. Astronomers have found that other solar systems are dangerous places to be with large gas giant planets orbiting close to their suns, and planets in eccentric orbits being thrown into the sun or out into deep space.

The discovery may have implications for the Search for Extra-Terrestrial Intelligence.
It may limit the number of relatively safe solar systems available for the establishment of life.

As well as the unique configuration, our solar system lies in the relatively safe outer reaches of one of the galaxy's arms, and the Earth is at the ideal distance from the Sun where water can exist in its liquid state.

[extract below]
Computer simulations put Solar System in its place
Posted: August 8, 2008
link to 'Astronomy Now' article

Traditional theories of Solar System formation assume our neighbourhood to be pretty run of the mill, but in a new study using data from 300 exoplanets discovered orbiting other stars, our planetary haven turns out to be one of a kind.

Before the discovery of the first exoplanets, our own Solar System's planets were the only ones known to us, so astronomers had no reason to think it unusual. But thanks to powerful computer simulations based on the data acquired from 300 exoplanets discovered over the last 15 years, theoretical astronomers from Northwestern University have been able to understand planetary system formation in a much broader sense, and have made the alarming discovery that planets being thrown mercilessly into the Sun or jettisoned into deep space could have been the destiny of our Solar System had its initial conditions been just a slightly bit different.

"Now we know that other planetary systems don't look like the Solar System at all," says Frederic Rasio. "The shapes of the exoplanets' orbits are elongated, not nice and circular. Planets are not where we expect them to be. Many giant planets similar to Jupiter, known as 'hot Jupiters,' are so close to the star they have orbits of mere days. Clearly we needed to start fresh in explaining planetary formation and this greater variety of planets we now see."
(Windows users - you can download the images to your PC if you right-click on them and select 'Save Picture As' (or 'Save Image As'). I believe Apple Mac users can use CTRL + click on the images.)

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