Slashdot Mirror

← Back to Stories (view on slashdot.org)

Ultra-Dense Galaxies In the Early Universe

Posted by kdawson on from the it's-little-it's-lovely-it-lights dept.

Science Daily is reporting on the characterization of a population of ancient galaxies, formed less than 3 billion years after the Big Bang, that are as massive as some modern galaxies but are only 1/20 the size. Each of the 9 compact galaxies found is less than 5,000 light-years across, and could fit comfortably inside the Milky Way's central hub (if you moved the supermassive black hole out first). The stars in these galaxies were 1/2 to 1 billion years old when observed and at least one generation of massive stars had already exploded as supernovae.

19 comments

  1. A science fiction reference by Anonymous Coward · · Score: 1, Interesting

    Poul Anderson's Tau Zero makes the suggestion that interstellar contacts between races are more likely in the beginning of the universe than towards the end, simply because all matter will spread so far apart and there won't be enough fuel to move around.

    Gene Wolfe's Book of the New Sun also conjectures a future where galaxies move so far apart that the steersmen of ships cannot locate their destinations by sight and must rely on old charts.

    1. Re:A science fiction reference by MightyMartian · · Score: 2, Insightful

      Poul Anderson's Tau Zero makes the suggestion that interstellar contacts between races are more likely in the beginning of the universe than towards the end, simply because all matter will spread so far apart and there won't be enough fuel to move around.


      That's a little silly. Even though the galaxies and stars must have been much closer together again, I don't think that any period where the distance would have made any substantial distance to traversing interstellar or intergalactic distances that the universe would have been around long enough to produce intelligent life, and, considering if these kinds of galaxies were the norm, I'm not even sure life, or at least complex life, would even be possible. Densely packed galaxies like this, with supernovae going off, would likely be very very radiation-rich.
      --
      The world's burning. Moped Jesus spotted on I50. Details at 11.
    2. Re:A science fiction reference by amRadioHed · · Score: 1

      Right, these dense galaxies are only 1/20th the size of the Milky Way, and that talking about volume I believe so actual differences in travel time will be less then an order of magnitude. Not going to make much of a difference when it comes to interstellar travel.

      --
      We hope your rules and wisdom choke you / Now we are one in everlasting peace
    3. Re:A science fiction reference by dryeo · · Score: 1

      The radiation density is something most people never think about. Not only would there be more supernova but also areas rich in star formation also put out quite a bit of radiation.
      Even now in our galaxy there is a large percentage of it that is inhabitable and not only that but I understand the majority of stars are in orbits around the core that are elliptical enough to pass close or through the core regularly.
      Another problem with areas of space that are packed with stars is the odds that other stars will pass by close enough to perturb the orbits of any planets is quite a bit higher.

      --
      https://en.wikipedia.org/wiki/Inverted_totalitarianism
  2. No Parking by Sta7ic · · Score: 4, Funny

    'course, all those galaxies would still fit if you DIDN'T move the supermassive black hole first. You'd just have to remove "comfortably" from the statement.

    1. Re:No Parking by kalirion · · Score: 1

      Everything fits with a supermassive black hole. Or rather in a supermassive black hole.

    2. Re:No Parking by repapetilto · · Score: 1

      besides your mom, of course

  3. Just out of curiosity - how far away are they? by mmell · · Score: 4, Interesting
    Or - to put it more bluntly - how long ago did they look like that?

    If they're over thirteen million light-years distant, they might represent a tantalizing glimpse into the physics of galaxy formation shortly after the Big Bang - the presence of heavier-than-helium elements indicates that at least one round of (superheavy) star formation/destruction has taken place, but they could still be relatively good examples of galactic physics in the (then neonatal) Universe.

  4. /s/million/billion by mmell · · Score: 1

    Oops - off by an order of magnitude. Mea culpa.

    1. Re:/s/million/billion by hanover.fiste · · Score: 1

      Oops - off by an order of magnitude

      Three orders of magnitude, Shirley. (10^^6 vs 10^^9)

    2. Re:/s/million/billion by Anonymous Coward · · Score: 0

      Are you sure it's not 3 orders of magnitude?

      But anyway, what are 2 orders of magnitude between astronomers once you plot everything on logarithmic scales.

  5. if you moved the supermassive black hole out first by Anonymous Coward · · Score: 0

    Yeah, first thing I'll do in the morning. Promise, dear.

  6. Interesting, but no big surprise.... by syousef · · Score: 1

    ...when the whole Universe was much denser at that stage. It's still good science, and another piece of information the human race possesses (especially in the detail) but I'm unsurprised.

    --
    These posts express my own personal views, not those of my employer
  7. Probably won't matter much by Moraelin · · Score: 2, Interesting

    The thing is, the rate of new star formation is decreasing over time.

    While technically there still is plenty of hydrogen left, the quantity of _free_ hydrogen (available for a new star) is becoming gradually more rare. More and more is locked inside old dead stars. Even a supernova doesn't eject all the matter in the star. A red giant only sheds the outer layer, or to put it other wise, does about as much to recycle the star as shedding does to recycle your dog ;)

    So basically if we're talking 100 billion years in the future -- which was the last number I heard for a universe where nothing is visible outside the galaxy -- there may be a rather extreme shortage of stars like the sun, and of civilizations trying to make contact with each other.

    --
    A polar bear is a cartesian bear after a coordinate transform.
    1. Re:Probably won't matter much by Luyseyal · · Score: 1

      Guess we'll just have to figure away to recycle all those old stars. Looks like we have some time to figure it out. :)

      -l

      --
      Help cure AIDS, cancer, and more. Donate your unused computer time to worldcommunitygrid.org. Join Team Slashdot!
  8. Citation by LightPhoenix7 · · Score: 1

    Science Daily isn't announcing anything, they just regurgitate press releases.

    A team of astrophysicists at Yale have published a paper in The Astrophysical Journal Letters. They're the ones announcing it.

    1. Re:Citation by Anita+Coney · · Score: 1

      The blurb says "reporting" not "announcing." Maybe they've fixed it since I showed up.

      --
      If someone says he and his monkey have nothing to hide, they almost certainly do.
  9. Imprecision Annoys by SWestrup · · Score: 2, Interesting

    Am I the only one annoyed by such an imprecise expression as "1/20th the size". One doesn't know from reading it if this is 1/20th the linear dimensions, or 1/20th the volume. (Turns out its the former, which makes it 1/8000th the volume, which is far more interesting.)