Five 'Supermassive' Black Holes Discovered

2»

Comments

  • spiney2spiney2 Posts: 27,058
    Forum Member
    ✭✭✭
    Mudbox wrote: »
    I think that there are only incipient black holes(that is no event horizon or singularity) anyway, but they act the same as black holes, and that some sort of pre-Hawking radiation would be emitted rather than Hawking radiation.

    a neutron star doez not emit hawking radiation as it has no event horizon.
  • MudboxMudbox Posts: 10,110
    Forum Member
    ✭✭
    spiney2 wrote: »
    a neutron star doez not emit hawking radiation as it has no event horizon.

    I personally don't think you need an event horizon to have some kind of radiation.. I have read the term 'preHawking radiation', for compact, collapsing objects that don't form event horizons
  • spiney2spiney2 Posts: 27,058
    Forum Member
    ✭✭✭
    Mudbox wrote: »
    I think I read that A.C.Clarke book.....I didn't, and don't understand how the black hole drive could work...not without Hawking radiation.

    tbe idea was proposed before hawking radiation was known.
  • spiney2spiney2 Posts: 27,058
    Forum Member
    ✭✭✭
    Mudbox wrote: »
    I personally don't think you need an event horizon to have some kind of radiation.. I have read the term 'preHawking radiation', for compact, collapsing objects that don't form event horizons

    this is esoteric stuff relying on an idealised asymtopic observer, and since the,universe is finite, i'll just stay with good old fashioned traditional black holes thanks.
  • MudboxMudbox Posts: 10,110
    Forum Member
    ✭✭
    when was the idea of a BH drive first proposed? Hawking radiation was proposed in 1974.

    The wiki page says that a black hole drive uses the Hawking radiation to drive the ship.

    https://en.wikipedia.org/wiki/Black_hole_starship
  • spiney2spiney2 Posts: 27,058
    Forum Member
    ✭✭✭
    reminds me of electromagnetism where you move an infintessimal charge an infinite distance to define potential ....
  • spiney2spiney2 Posts: 27,058
    Forum Member
    ✭✭✭
    Mudbox wrote: »
    when was the idea of a BH drive first proposed? Hawking radiation was proposed in 1974.

    The wiki page says that a black hole drive uses the Hawking radiation to drive the ship.

    https://en.wikipedia.org/wiki/Black_hole_starship

    clarkes book is something like 73 and the original idea predates hawking. It is in effect just a super efficient rocket ......
  • spiney2spiney2 Posts: 27,058
    Forum Member
    ✭✭✭
    wikipedia gives,86 for novel publication date but thats still well before the link mentioned above ........ Clarke does mention the original physics journal in his novel in appendix ....
  • MudboxMudbox Posts: 10,110
    Forum Member
    ✭✭
    well I think, if you shove something in a black hole, I think you get jets of stuff coming from the poles.....maybe those jets were proposed to have pushed the ship forward.
  • TelevisionUserTelevisionUser Posts: 41,404
    Forum Member
    swingaleg wrote: »
    I thought current theory was that every galaxy had a supermassive black hole at the centre, including ours

    Yes, that's the generally accepted theory but it's just that some galactic centre black holes have been particularly elusive like the ones in this most recent report.

    The huge black hole at the centre of this galaxy is rather active, it's orbited by a number of stars and a gas stream and there is a report from earlier on in the year here: Milky Way's Monster Black Hole Unleashes Record-Breaking X-ray Flare

    It is safe to say that I do not recommend the core of the Milky Way Galaxy as a tourist destination.
  • zx50zx50 Posts: 91,227
    Forum Member
    ✭✭✭
    ilar wrote: »
    So how come a universe with a super massive black survives if the black hole sucks everything around it in. It must be a bit like pulling a coner of a table cloth through a curtain ring its got to come to an end at some time - unless it's all coming out the other end into an alternative universe - perhaps a negative of the original.

    The one at the centre of our Milky Way is being somehow starved of the fuel it needs to become a threat to everything else in the Milky Way.

    Edit: Being starved of what it needs to get started on eating our galaxy up. I'm assuming everything else would follow.
  • zx50zx50 Posts: 91,227
    Forum Member
    ✭✭✭
    Mudbox wrote: »
    black holes don't suck everything up in the same way stars don't suck everything up. Black holes are just gravitational bodies, and their gravitational pull drops of quickly the further you are away from them, just like stars and planets.

    Things just orbit black holes. Like the one at the centre of our galaxy, everything else just revolves around it; it doesn't suck anything up, unless it gets too close to it.

    That could be why ours hasn't started to eat our galaxy up. The closest objects to it, massive Suns (compared to ours), they're quite a distance from it.
  • Richard46Richard46 Posts: 59,830
    Forum Member
    I will start worrying if it turns out they are holes in an enormous sock.

    Then I guess it is sorry God I was wrong all along.
  • CravenHavenCravenHaven Posts: 13,953
    Forum Member
    ✭✭
    It is safe to say that I do not recommend the core of the Milky Way Galaxy as a tourist destination.
    it's okay, it's the fluffy kind of nougat not the hard stuff
  • degsyhufcdegsyhufc Posts: 59,251
    Forum Member
    bryemycaz wrote: »
    So what is it?
    Wrong coloured hole
  • MudboxMudbox Posts: 10,110
    Forum Member
    ✭✭
    Black Holes are Actually "Eternally Collapsing Objects" --Indian Physicist Refutes Hawking
    http://www.dailygalaxy.com/my_weblog/2014/11/black-holes-are-actually-eternally-collapsing-objects-indian-physicist-refutes-hawking.html
Sign In or Register to comment.