Please turn on javascript in your browser to play chess.
Science Forum

Science Forum

  1. Standard member sonhouse
    Fast and Curious
    18 Aug '15 17:13
    http://phys.org/news/2015-08-solar-formation-dont.html

    It seems the nascent cloud around our proto sun needs a kick in the butt to start the cloud spinning around the sun. Without the spin the stuff just gets pulled into the new star.
  2. 19 Aug '15 06:42
    Originally posted by sonhouse
    http://phys.org/news/2015-08-solar-formation-dont.html

    It seems the nascent cloud around our proto sun needs a kick in the butt to start the cloud spinning around the sun. Without the spin the stuff just gets pulled into the new star.
    My understanding is that all clouds of dust contain some inherent spin.
    Given that nearly every star has planets it would seem that there is either a flaw in the article or nearly every planetary system required some equivalent kick start.
  3. 19 Aug '15 08:48
    Originally posted by twhitehead
    My understanding is that all clouds of dust contain some inherent spin.
    Given that nearly every star has planets it would seem that there is either a flaw in the article or nearly every planetary system required some equivalent kick start.
    Is this really a fact? That nearly every star has planets? I wouldn't think so...
  4. 19 Aug '15 09:02
    Originally posted by FabianFnas
    Is this really a fact? That nearly every star has planets? I wouldn't think so...
    It is a fact that the majority of stars have planets. I do not have exact statistics.
  5. 19 Aug '15 09:58
    Originally posted by twhitehead
    It is a fact that the majority of stars have planets. I do not have exact statistics.
    How about gen I stars? Do they have planets? As far I know they don't.
    What is your source of information?
  6. 19 Aug '15 10:22
    Originally posted by FabianFnas
    How about gen I stars? Do they have planets? As far I know they don't.
    What is your source of information?
    I have not been able to find clear statistics, but am talking based mostly on watching a number of different talks on Kepler data.

    https://en.wikipedia.org/wiki/Exoplanet
    There is at least one planet on average per star.

    Note that the above statistic is a minimum.

    About 1 in 5 Sun-like stars have an "Earth-sized" planet in the habitable zone,

    This one seems more definite. It seems to me that it implies that more than 50% of stars would have at least one planet.
  7. Standard member sonhouse
    Fast and Curious
    19 Aug '15 10:29
    Originally posted by twhitehead
    I have not been able to find clear statistics, but am talking based mostly on watching a number of different talks on Kepler data.

    https://en.wikipedia.org/wiki/Exoplanet
    There is at least one planet on average per star.

    Note that the above statistic is a minimum.

    [quote]About 1 in 5 Sun-like stars have an "Earth-sized" planet in ...[text shortened]... nite. It seems to me that it implies that more than 50% of stars would have at least one planet.
    It would make sense to think of the interaction of supernovae with nascent solar systems. A supernova will send a shock wave hundreds of light years in all directions, almost all anyway, and therefore any new suns born in that volume of space would ALL get a kick start, all the clouds of stuff around those new born suns shaken up by the massive energy output of that nova. So one supernova can send shock waves in a volume of space 20 million cubic light years. A far size chunk of the entire galaxy. It wouldn't take many such nova's to jump start planetary processes in an entire galaxy.
  8. 19 Aug '15 10:42 / 1 edit
    Originally posted by twhitehead
    I have not been able to find clear statistics, but am talking based mostly on watching a number of different talks on Kepler data.

    https://en.wikipedia.org/wiki/Exoplanet
    There is at least one planet on average per star.

    Note that the above statistic is a minimum.

    [quote]About 1 in 5 Sun-like stars have an "Earth-sized" planet in ...[text shortened]... nite. It seems to me that it implies that more than 50% of stars would have at least one planet.
    "There is at least one planet on average per star"

    Say ten stars with one solarsystem with 10 planets gives one planet on average per star.
    You avoid the gen I stars. Why so?

    About 1 in 5 Sun-like stars have an "Earth-sized" planet...
    Perhaps one in five Sun-like stars, ok, but Sun-like star are not very common.
  9. Standard member sonhouse
    Fast and Curious
    19 Aug '15 10:53 / 1 edit
    Originally posted by FabianFnas
    [b]"There is at least one planet on average per star"

    Say ten stars with one solarsystem with 10 planets gives one planet on average per star.
    You avoid the gen I stars. Why so?

    About 1 in 5 Sun-like stars have an "Earth-sized" planet...
    Perhaps one in five Sun-like stars, ok, but Sun-like star are not very common.[/b]
    Sun like stars are still quite numerous, rather on the large size galactically speaking, our sun is in the top 5% of star masses in the galaxy. Word on the street is sun like stars are only about 10% of all stars in the galaxy. Still, that leaves about 20 billion sun like stars in the Milky Way. They are also saying about 1 in 5 such stars has planets so 4 billion stars with planets around them. If we ever develop some method of going faster than light, it is going to be a field day for planetologists!
  10. 19 Aug '15 11:02
    Originally posted by FabianFnas
    How about gen I stars? Do they have planets? As far I know they don't.
    What is your source of information?
    Older, 'metal' poor stars might lack the 'metals' needed to form rocky planets...

    However they still have plenty of hydrogen and helium at the very least for the formation of gas giants.
  11. 19 Aug '15 11:05
    Originally posted by twhitehead
    My understanding is that all clouds of dust contain some inherent spin.
    Given that nearly every star has planets it would seem that there is either a flaw in the article or nearly every planetary system required some equivalent kick start.
    It might be that they don't have 'enough' spin...?

    I was of the belief that they needed a kick to start contracting, not to give spin.

    However star formation regions are pretty much guaranteed to have supernova in/near them as
    the bigger stars race through their fuel in ~1 million years or so.
  12. 19 Aug '15 11:23
    Originally posted by googlefudge
    Older, 'metal' poor stars might lack the 'metals' needed to form rocky planets...

    However they still have plenty of hydrogen and helium at the very least for the formation of gas giants.
    Yes, you're right.

    However, I see giant gas bodies not as planets but as brown dwarfs. But I know that I am in a minority to think like that.

    But do we really need a supernova shock to generate Jupiter kind of planets?
  13. 19 Aug '15 11:34
    Originally posted by FabianFnas
    Say ten stars with one solarsystem with 10 planets gives one planet on average per star. .
    As I said, it is a minimum.

    You avoid the gen I stars. Why so?
    Because I know nothing about how many gen 1 starts are in the galaxy. Please tell us what percentage of starts they make up.

    Perhaps one in five Sun-like stars, ok, but Sun-like star are not very common.
    So, find us a statistic for brown dwarfs which are much more common.
  14. 19 Aug '15 11:37
    Originally posted by sonhouse
    They are also saying about 1 in 5 such stars has planets......
    No. They are saying 1 in 5 has an earth sized planet in the goldilocks zone. The other 4 out of 5 may have plenty of planets.
  15. 19 Aug '15 11:39
    Originally posted by FabianFnas
    However, I see giant gas bodies not as planets but as brown dwarfs. But I know that I am in a minority to think like that.
    So you call Jupiter a 'brown dwarf'? How many planets do you think our solar system has?