Why is there SETI?

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Dinosaur, Aug 23, 2005.

  1. glenn239 Registered Senior Member

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    I watched a program last night on life in the galaxy. It indicated that the the theory binary star systems can't support life has been overturned upon closer examination.
     
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  3. may_wentee Registered Senior Member

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    Which binary star system you're referring too that upon closer examination has been found to have the potential for supporting life?

    May_wentee
     
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  5. glenn239 Registered Senior Member

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    Any which allow for planet to maintain stable orbits over the course of billions of years. It appeared as if the best case was if the stars are close together.
     
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  7. Dinosaur Rational Skeptic Valued Senior Member

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    Glenn239:Are you sure the following is correct?
    I would expect that best for stability would be a binary system with the stars far apart, but that is only a WAG.

    I assume that the planets in a binary system would orbit in the plane of rotation of the two stars.

    Did the article specify that the planets orbited around the center of gravity of the two stars or around one star? The former might be stable if the stars are close together, but I wonder how long such a system could last without the two stars coalescing into one. A planet orbiting one of the stars with the other nearby seems unstable.

    I would be interested in obtaining some specific details of such a system (mass of stars, distance between them, how planets are configured and their masses, et cetera).. I would like to do some gravitational calculations. I have a Visual Basic program written for Windows 98SE which might simulate such a system under XP.
     
  8. abyssoft Registered Senior Member

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    Planets in a binary system, in order to have stable orbits, need to orbit either close to each individual star at a maximum distance of 0.2* minimum separation of the two stars or orbit both stars at a minimum of 5 * Maximum separation of both stars.
     
  9. glenn239 Registered Senior Member

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    202
    It was a program, not an article.

    They didn't go into the math of it, but what abyssoft posts looks generally right. The binaries are close together, the hypothetical moon with life was postulated to be in orbit around a gas giant far outside the orbits of the central stars.
     

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