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What Came First, Black Holes Or Galaxies? 76

Posted by timothy
from the it's-the-one-that-respresents-the-chicken dept.
StartsWithABang (3485481) writes "It was one of the most hotly contested questions for decades: we first expected and then found supermassive black holes at the centers of practically all large galaxies. But how did they get there? In particular, you could imagine it happening either way: either there was this top-down scenario, where large-scale structures formed first and fragmented into galaxies, forming black holes at their centers afterwards, or a bottom-up scenario, where small-scale structures dominate at the beginning, and larger ones only form later from the merger of these earlier, little ones. As it turns out, both of these play a role in our Universe, but as far as the question of what came first, black holes or galaxies, only one answer is right."
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What Came First, Black Holes Or Galaxies?

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  • Answer (Score:4, Informative)

    by Anonymous Coward on Saturday July 05, 2014 @03:48AM (#47387335)

    So the best answer we have is that the seeds of supermassive black holes and the seeds of galaxies were what formed first, and they did so at approximately the same time. But these black holes began as quite large structures, growing to at least many thousands of solar masses before the environments in which they were housed could ever be considered galaxies, and so it appears that black holes came first, but they form in regions that will merge-and-grow into large, rich galaxies in very short order.

    The article has a pretty in-depth explanation (from what my layman's eyes can see) though.

  • Bah (Score:2, Insightful)

    by Anonymous Coward

    medium.com unreadable fluff. Please find a better website to spam. Not all of us have tablets, you know.

    • by Anonymous Coward
      Speaking of why Medium.com sucks...

      Why do stories on sites like Medium.com scroll so badly? Jerky, screen tearing...who would want this?

      Personally, I avoid sites like this. It is a trivial matter to type some of the article text into Google and find a different web site.

      But back to my question...Is it because of the mega large graphics/background? Can I just block that in some way? In Opera?
  • There need to be supermassive stars . Like this one which is 265 solar masses ! . Chandrashekars limit tells us that a star will collapse into a black hole at >= 5 solar masses . I somehow always imagined supermassive giants collapsing into black holes and galaxies forming around them . The question is is ther only one supermassive star in a galaxy ? or per galaxy? . What if another massive star in a galaxy goes supernova and collapses. will it disturb the gravitational balance?
    • http://en.wikipedia.org/wiki/R... [wikipedia.org] -- 265 solar masses
    • by Anonymous Coward

      To form supermassive blackholes There need to be supermassive stars

      Non sequitur. A supermassive black hole can form by the merger of smaller black holes, normal stars, interstellar gas, even dark matter. The only snag is that these things need to get close to each other, because - contrary to popular belief - black holes don't "suck".

    • by Almost-Retired (637760) on Saturday July 05, 2014 @09:17PM (#47391023)

      Not in the short haul because the mass that creates the gravity well usually stays within that galaxy. Long haul, as in several trillion years, the two black holes will orbit as before when they both were just stars, but the gravitational waves they emit is a loss of system energy and they will slowly spiral into each other until they merge. But that may take longer for most of them than the universe is old. We are actively looking for the gravity wave that would indicate two such black holes have merged as it will have a distinct waveform.

      Cheers, Gene

  • by Rosco P. Coltrane (209368) on Saturday July 05, 2014 @05:04AM (#47387457)

    I read somewhere that the heavens and the Earth came first.

    • by Livius (318358)

      What do you think the heavens are made of? Obviously all the parts of the heavens came first.

      • by rtb61 (674572)

        The multi-verse. From chaos, every thing, every where, every when, life enforced a singular time line, some thing, some where, some when because you can never have nothing, no where, no when. Although not to be fooled, time as such doesn't exist, it is just a life based relative measure of change.

  • Neither... (Score:2, Insightful)

    by bayankaran (446245)
    Not black holes, nor galaxies, but da chicken came first.
  • by rossdee (243626) on Saturday July 05, 2014 @07:54AM (#47387835)

    So how did the supermassive black holes get formed?

    • This. Observed black holes have so far been either 1) Stellar - tens or may be hundreds of solar mass or 2) Supermassive - millions to billions of solar mass. We haven't seen anything in between. So with the data at hand, the question is: Are Supermassive are formed from big bang or they are "formed" as they pull heavenly bodies towards them?
  • But what if a galaxy formed, then after a few billion years collapsed entirely into the central black hole, which then caused a new galaxy,...
    (leading vaguely to a Yo Dawg meme here)

  • Is this not too dissimilar to how we think the solar system started, the sun first and then the planets?
  • Both? (Score:5, Interesting)

    by fygment (444210) on Saturday July 05, 2014 @08:16AM (#47387901)

    Why is the answer always assumed to be binary? Both processes could have been occuring simultaneously.

    • by mbone (558574)

      Why is the answer always assumed to be binary? Both processes could have been occuring simultaneously.

      I am sure both were occuring simultaneously, the question is, which dominates? The two sets of processes have different time constants (growth rates), arising from different physics. For both to be more-or-less equally powerful requires these time constants to be more-or-less matched, and that seems improbable and fails "Occam's razor" type "tests."

      So, could be, but don't expect that idea to gain traction, at least without a good theory as to why things should be that way.

      • by mbone (558574)

        Of course, as the "With a Bang" article points out, if you are willing to wait and not have everything be simultaneous, you can have both large scale structure formation and small scale structure formation going on simultaneously, with the small scale going to completion earlier, and both together yielding what we see today.

    • by mick129 (126225)
      From The Fascinating Article:

      In other words, both the top-down and the bottom-up scenarios play a role, but the bottom-up, by virtue of starting smaller, gets a head start by millions of years!

      The answer is not assumed to be binary.

  • Of course black holes.

    Then galaxies.

    But super-massive black holes - the interesting question - probably came last, although they avoided that aspect of the question.

  • we first expected and then found supermassive black holes at the centers of practically all large galaxies.

    "expected" is sure not how I remember it, and in fact I think this has the historical record backwards. Quasars were definitely a surprise, and the Super Massive Black hole (SMB) interpretation of quasars took a while (a decade at least) to catch on, and the consensus that most galaxies have a central SMB came after that, after some local galaxies (such as our own) showed signs of having a SMB too. Be

  • by mbone (558574) on Saturday July 05, 2014 @11:55AM (#47388775)

    Having read the article, I think that "With a Bang" sort of waffled on this. It is hard to see [arxiv.org] how SuperMassive Black holes (SMB) form in the time available for them to form. (There is a large literature on this, but basically there are problems of the seeds - are the seeds Pop III stars, or something more exotic - and time - how can the mass move around enough to form SMB by z ~ 6?).

    I don't really feel you can safely answer the "which came first" question until you know how the SMB actually formed.

    A one hour video lecture, Supermassive Black Holes and the Problem of Galaxy Formation [youtube.com], might be interesting to people interested in these problems, but it deals with the galaxy problem more than the SMB problem.

    • by Rich0 (548339)

      Thanks for the link - haven't watched it yet.

      I've always wondered if Galaxies and SMB are both effects from a common cause. We don't understand dark matter, and that is a HUGE gap when it comes to galaxy formation. If there is some kind of primordial force at work that created the large-scale structure of the universe then perhaps SMB are just an extreme manifestation of it. They didn't necessarily form from steller evolution. Maybe at some period in the past if not today there were huge gravitational g

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