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So what is the consensus now?

  1. Apr 2, 2005 #1
    Is our solar system still considered as "run of the mill" or now unique with that space.com article coming out?
     
  2. jcsd
  3. Apr 2, 2005 #2

    SpaceTiger

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    Still largely unknown. So far, we've mostly only been able to chart systems unlike our own.
     
  4. Apr 2, 2005 #3

    tony873004

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    I'd consider us to be less "run of the mill" than I'd have considered us to be 10 years ago. Back then I wouldn't have imagined that systems with hot Jupiters existed. In the past 10 years, we've ruled out the possibility that all other systems are just like ours.

    Look at the moon systems in our solar system. They're all very different. There isn't one that could be considered "run of the mill".

    I have a feeling that star systems are going to be very diverse too. But with so many out there, there's bound to be lots of them that are similar to ours.

    SpaceTiger is right. Until we have the ability to detect solar systems like our own, this will remain an unanswered question.
     
  5. Apr 2, 2005 #4
    So, what is it that makes our solar system special or unique, except for the fact it has got life and Earth.
     
  6. Apr 2, 2005 #5
    When you ignore the Earth bit, there probably isn't that much that makes us *really* unique. However I think it's rare enough to have planets, let alone Jupiter-sized ones at the right distance and small rocky ones in the habitable zone, to make us special.
     
  7. Apr 3, 2005 #6
    But of course there would still be a large amount of them right?
     
  8. Apr 3, 2005 #7

    marcus

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    AFAIK for 10 years or so there has not been a consensus among the involved astronomers, space science, planet science people concerning such typicality. Since the mid 1990s I doubt there has been an informed consensus that the solar system was typical

    On the contrary, to the best of my knowledge quite a few folks have been wondering, for some ten years now, why did the solar system turn out so different from others? How can you explain our system being so different from the "run of the mill" that the exoplanet search has found. Several explanations (none altogether satisfactory) have been offered.

    I talked with people in the exoplanet search in 1996 and read reports and stuff etc. I never got the impression that any knowledgeable person supposed that the solar system was "run of the mill"

    there just has not been enough evidence, and what there is even points in the opposite direction! the admittedly biased sample we have so far has suggested NON-typicality.

    Admittedly biased because massive planets close in are easier to detect. but even after trying to allow for the bias there is still puzzlement as to why the other systems are so different from us.

    Now that is simply my impression. (I dont have statistics or an opinion poll of scientists or anything like that!) You may have a different impression from those you have talked to.
     
    Last edited: Apr 3, 2005
  9. Apr 3, 2005 #8

    marcus

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    tony and SpaceTiger already gave good answers, I had to be away and didnt see it was taken care of until I replied. sorry.

    about why are we unusual, look at the statistics, try to find a Jupiter size planet that is 5 AU from its star, in an almost circular orbit

    my impression is that those other systems have a lot of eccentric orbits (not circular) and a lot of giant planets in very close, probably boiling off their atmospheres. they are weird.

    what kept our giant planet from spiraling in close to the sun, as so many others did?

    jupiter has done us the favor of flinging crud out of the inner solar system that might have bumped us

    check out the list and see if you can find any other system with a giant at 5 AU and approximate zero eccentricity.
     
  10. Apr 3, 2005 #9

    marcus

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    I see no reason to doubt that there are zillions of habitable planets in the Milkyway galaxy. Aside from Fermi's paradox.

    but what seems more interesting is the statistics of planetary systems, quite apart from habitability, why do they form the way they do. why do so many have gas giants bigger than jupiter but in closer than mercury?

    (besides the fact that these are the easiest to detect :smile: )
     
  11. Apr 3, 2005 #10
    The only reason I can think of is because of detection bias, since these "wobbles" from Hot Jupiters are easier to detect then they are the ones that we do detect? maybe?

    I dont think solar system's like ours is common but I also dont think it is rare, I think there would be a fair amount of them.
     
  12. Apr 3, 2005 #11

    Chronos

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    I don't like to appeal to the principle of mediocrity [sounds like anthropery], but I think it applies. I think it is unlikely a solar system like this is particularly rare in a galaxy this large.
     
  13. Apr 3, 2005 #12
    So Chronos is your view getting changed a little bit now?
     
  14. Apr 3, 2005 #13

    Chronos

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    No. In my view [and I think I have been consistent on this], a solar system like this is not terribly rare among stars similar to ours.
     
  15. Apr 3, 2005 #14

    marcus

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    Chronos, Goldbars, Tony, Tiger and others. Should we start a new thread that is not about (I think rather distracting) speculations about exolife possibilities but is focused purely on the scientific puzzle of

    exoplanet statistics?

    I would like to know what other people here are thinking about how the very strange statistics can be explained. It is too striking (it seems to me) to be attributed to observational bias (giants close in easier to detect)

    there is an overwhelming number of giants close in, even compared to giants at 1 AU, which are certainly detectable!

    could somebody link us to a graph of the statistics?

    Should we have a separate thread so as not to misappropriate Goldbars'?

    that is really for him to decide I guess. maybe it would be neater.
     
  16. Apr 3, 2005 #15
    I dont really care, its up to y'all

    How many Sun-like stars have we discovered? and does its planets have eccentric orbits?
     
  17. Apr 3, 2005 #16

    turbo

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    Goldbarz (and others) you may enjoy this streaming-video lecture on exobiology. The Mars rovers show us that Mars once had a watery surface, and may have been able to support life similar to that here on earth.

    http://forum.wgbh.org/wgbh/forum.php?lecture_id=1722

    There are some nice presentations on the WGBH web site, so you may want to bookmark it and browse the category listing from time to time when you need a science "fix".
     
  18. Apr 4, 2005 #17
    I think they dont have enough evidence to claim that our solar system is rare...
     
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