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Black Holes

Discussion in 'Science & Technology' started by Drone, Sep 24, 2011.

  1. Drone

    Drone

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    So no wimps for today I guess...

    Yeah small but darn heavy

    More ...

    They think that a tiny primordial black hole could move through the sun ....

    ... every millions of years. I guess I'd get bored to wait so long but ...

    Would be funny if those oscillations were spotted but nobody thought it was tiny nasty black holes. But there's a hope ...

    Atm it all adds only confusion.
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  2. Inceptor

    Inceptor

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    I can't see dark matter being primordial black holes.
    It's well established that dark matter surrounds galaxies, galactic clusters, and superclusters. This has been observed simply from inferring gravitational interactions with the visible galaxies.
    It has to be WIMPS in some form or other. Primordial black holes would not survive billions of years in cosmically significant numbers to gravitationally influence galaxies without announcing themselves with gamma ray and x-ray emissions as they coalesce and merge (not gamma ray bursts, those are supernovae). Furthermore, those primordial black holes (if they were that numerous) would have merged into a lesser but still massive number of black holes with billions of solar masses, in order to gravitationally influence 'visible' baryonic matter.

    I'm sure there are innumerable primordial black holes out there, but they can't account for all the mass of 'dark matter'.
  3. Drone

    Drone

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    Nice. I believe in WIMPS too. I think they claim this because atom-sized black holes are just hard to detect as wimps. But I dunno what if black holes are made of wimps (or superwimps).
  4. Inceptor

    Inceptor

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    WIMPs are Weakly Interacting Massive Particles; which implies they're all floating around out there, and don't interact with normal matter or with each other much at all; so gravitationally coalescing into black holes is ruled out. Imagine large cluster spanning clouds of dark matter particles (WIMPs) gravitationally affecting the visible matter in a galaxy or cluster of galaxies.

    Here's some reports on it:
    http://arstechnica.com/science/news/2008/01/images-of-dark-matter-distribution-in-a-supercluster.ars

    http://home.slac.stanford.edu/pressreleases/2006/20060821.htm
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  5. Drone

    Drone

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    I know what wimps are. Weak is still interaction.

    http://www.nasa.gov/mission_pages/GLAST/science/dark_matter.html

    When supersymmetic neutralinos (aka wimps) interact with each other they annihilate and create secondary particles (leptons, bosons, quarks) and gamma rays. I wasn't talking about "gravitational coalescence". Just interaction. And second: I was talking about WIMP matter and a question whether black holes were made up of WIMP matter or regular matter.

    http://adsabs.harvard.edu/full/2002Obs...122..199A
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  6. Inceptor

    Inceptor

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    That's interesting stuff, but it's all theoretical and speculative.
    I first read about WIMPs and MACHOs 25 years ago, and all that can be said, so far, is that MACHOs can possibly account for a very small percentage of what we call dark matter. The problem is that we have no way of knowing, at this point, what MACHOs really are.

    Also, I have to point out that a black hole, being the remnant of a massive star, composed of baryonic matter, collapsed down to a point that is at most Planck length in diameter... that's all we can know about it. Physics can't tell us anything about what happens in there; it's just a massively compressed soup of energy, as to details... who knows? There are no particles, just energy. No dark matter in a normal black hole, just energy.

    Dark matter stars and dark matter black hole analogs? Interesting but not proven.
    Last edited: Oct 4, 2011
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  7. Drone

    Drone

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    You're right. We don't have enough knowledge of that. All these things are so hard to detect/observe and it breeds a lot of speculations. (atm I'm reading the links you posted above). Many scientists even introduced wimp-less models (with much lighter particles than wimps, I bet you've heard about that theories). You can see it here: http://www.physorg.com/news148316483.html. They say what if there are other kinds of interactions we don't know about. Sounds so crazy. They also talk about shadow world.

    Very interesting (supersymmetry) points. This once again reminds of shadow world. Maybe at the end of the day there are other forms of interactions and many undetectable particles. In this case I think humanity will ought to re-examine all their models and knowledge. I hope quantum physics will move forward so humankind will have more knowledge about all this process.

    And back to black holes. I don't like to quote wiki but however:

    http://en.wikipedia.org/wiki/Dark_matter

    The other day I remember one person (as a joke) said that what if there's no missing mass in the universe, and it's just the lack/absence of anti-gravitational forces/interactions. Lol now what if it's like that for real. And now I wonder are black holes just collapsed stars or they were created in some other process. Or there are different kinds of black holes and their origins. If scientists can ever generate a black hole maybe that will explain everything.
  8. Drone

    Drone

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    Heh nice news. Congrats Adam Reiss, Saul Perlmutter and Brian P. Schmidt. I gotta read more about their work.

    edit: I rather put this in the new thread

    http://www.techpowerup.com/forums/showthread.php?p=2419800#post2419800
    Last edited: Oct 9, 2011
  9. micropage7

    micropage7

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    i dunno
    the universe is too big to think about
  10. Drone

    Drone

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    I continue the topic about the dark matter. Here's some news:

    NASA’s Fermi Team located 1873 new sources and 1/3 of them is a mystery. It emits gamma rays but they have no idea what is this. As always dark matter rears its head again.

    Last edited by a moderator: Nov 20, 2013
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  11. hat

    hat Maximum Overclocker

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    What about "normal" black holes that are created today? Couldn't those be considered dark matter as well, then?
    Crunching for Team TPU
  12. Inceptor

    Inceptor

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    No. "Normal" black holes aren't created in large numbers. You need a supernova explosion (or coalescing neutron stars), and there are only a handful of those every year in a galaxy the size of ours (which is a fairly large sized galaxy). So, the number of black holes 'born' every year, throughout the universe, while large, is still a miniscule amount of mass compared to the 'invisible mass' of dark matter.
    Anyway, I think that estimations of total black hole mass are part of the 'visible matter' percentage totals.

    Edit: Maybe a 'handful' of supernovae per year in our galaxy is a bit too much, but it's a single digit number/year.
    Last edited: Oct 20, 2011
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  13. scoutingwraith

    scoutingwraith

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    Hmm....an interesting theory. Always thought that Dark matter is the product that existed outside before the big bang. Although havent read upon it a lot because i have no time do so. (will look up some papers though)
  14. Drone

    Drone

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    Birth of Famous Black Hole Unraveled

    Don't wanna create a new thread so here it goes:

    [​IMG]

    That suckah is big. Literally.

    Just like a big big Black Box ...

    800 RPS, wow!

    Lol that's for sure

    And finally this ...

    Dark matter anyone? Anyone at all?

    Anyway it's kickass and very important news.

    http://www.sciencedaily.com/releases/2011/11/111117144045.htm
  15. Inceptor

    Inceptor

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    Could be dark matter born, I guess.
    But it could just have been a free floater, kicked in some direction by its supernova blast, at some point, and gravitationally captured by its companion. Unlikely, but possible, considering how many stars there are out there.
    OR the result of a neutron star merger that was gravitationally captured by the companion star.
    OR it was made by someone or something a long long time ago.
  16. scoutingwraith

    scoutingwraith

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    If it was a Neutron star collapsing wont there be any traces left of it. (like residual radiation or on the x-ray spectrum) ?
  17. Inceptor

    Inceptor

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    If it was a neutron star merger, the two neutron stars would merge, then gravitationally collapse creating a black hole, and in the process release a massive gamma ray burst that apparently would 'sterilize' the surrounding region, a few thousand light years in all directions. But after the formation of the black hole, there would be no emitted radiation we could detect (aside from the radiation emitted from the material spiraling into the black hole).

    I kind of like the idea of it being a black hole formed from dark matter.
  18. hat

    hat Maximum Overclocker

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    15 times more massive than the sun, huh? I thought black holes were created through starts hundreds or thousands of times more massive than our sun when they die in a supernova. I guess there are other ways for black holes to be made...?
    Crunching for Team TPU
  19. Drone

    Drone

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    If you have read the whole article you'd know that this black hole got nothing to do with supernovae
  20. twilyth Guest

    There's a great series of documentaries on black holes on the science channel. Here are some interesting facts from memory.

    The milky way has about 10,000 black holes in the galactic center and the largest is several million solar masses.

    All galaxies have black holes at their center.

    The mass of a galactic black hole is always about 1.5% of the total galactic mass.

    Andromeda has a black hole that is 30 million solar masses.

    M87 has one that is 1 billion solar masses.
  21. Drone

    Drone

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    Kepler (NASA satellite, launched in March 2009 to orbit the Sun) could reveal if PHB (primordial black holes) are dark matter.

    Well ... the problem is scientists don't know how PHBs got formed and they don't know how massive they can be. Basically they just want to "weed out" some crap to narrow down the range of possible PHB mass. If they succeed they can say is PHB dark matter or not, if they fail they just eliminate useless factors. Let's say it's a win win situation.

    "Collapse of string loops" I haven't heard about this. Gotta read when I find some info about that. If anyone has a link, please post it.

    [​IMG]

    As always gravity is they key. So MACHO or PHB? Let's see:

    However scientists ain't too optimistic about this. Sure, we still couldn't find dark matter in entire space nor in LHC, but on the bright side, Kepler's photometer with its extreme precision has a chance to detect a thing or two and maybe they can solve this 50 year old mystery. I hope :)

    http://www.physorg.com/news/2011-12-nasa-satellite-reveal-primordial-black.html
  22. Aleksander

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    The dark matter is no more in physicists discussion after the neutrino speed.
    It is like using einstein's law to find infinitely something which you don't even know.
    Either neutrino is right or wrong for the speed part, dark matter is not and has nothing to do
    with einstein law's. It was found out, as something which cannot be explained.
  23. Inceptor

    Inceptor

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    The Kepler mission has a limited lifetime.
    The chances of it being used to specifically look for microlensing events is small, planet hunting is sexier and has more public visibility. Especially with the news that detecting the transits of Earth analogues will require a lengthening of the mission in order to attain more statistical certainty.
    Unless the dark matter researchers can use the same data sets for their analysis.
  24. Drone

    Drone

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    I don't think that one can hinder other. Because:

    If dark matter plays a big part in this then it's even more important.
  25. Drone

    Drone

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    http://www.physorg.com/news/2011-12-galaxies-big-dark.html

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