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Thread: Black hole photo

  1. #1
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    Black hole photo

    Why is it so difficult to get the photo of a black hole?

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    because they are often small, partly. A bh the mass of the sun would only be 12miles across I think.

    I read that they were attempting to get a picture of the smbh at the centre of the galaxy this year.. that's a lot bigger.
    Last edited by WaxRubiks; 2018-Jan-10 at 12:04 PM.
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    Because they produce no light. They are also very small. If I remember, a Solar-mass black hole is about one meter in radius.

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    But can’t you get a photo of the distorted space around it?

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    Quote Originally Posted by gzhpcu View Post
    But can’t you get a photo of the distorted space around it?
    The distorted space around it is very small, too.

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    Sorry that the title is "black photo", instead of "black hole photo"....

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    Quote Originally Posted by swampyankee View Post
    Because they produce no light. They are also very small. If I remember, a Solar-mass black hole is about one meter in radius.
    Three kilometres. (Still small.)

    Grant Hutchison
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    Quote Originally Posted by gzhpcu View Post
    Sorry that the title is "black photo", instead of "black hole photo"....
    Fixed

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    The distortion of the background stars at the visible edge of the sun is very tiny and difficult to measure. It would be no greater if the sun were collapsed into a black hole, there would only be visible distortion for a small fraction of the sun's visible size. Imaging the distortion from a stellar mass black hole would be harder than imaging the star it came from.

    For bigger black holes: Sagittarius A* is about 4 million solar masses, but is also about 1.6 billion times further away than the sun, and observable only in certain wavelengths due to dust.

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    Quote Originally Posted by grapes View Post
    Fixed
    Thanks

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    Quote Originally Posted by Mudskipper View Post
    I read that they were attempting to get a picture of the smbh at the centre of the galaxy this year.. that's a lot bigger.
    2018 Will Be The Year Humanity Directly ‘Sees’ Our First Black Hole
    The telescopes comprising the Event Horizon Telescope took their very first shot at observing Sagittarius A* simultaneously last year. The data has been brought together, and it’s presently being prepared and analyzed. If everything operates as designed, we’ll have our first image in 2018.

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    gzhpcu, keep in mind that this "image" will not be a visible light photograph, but a radio wavelength image (translated into visible wavelengths for human eyeballs).
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    Quote Originally Posted by gzhpcu View Post
    But can’t you get a photo of the distorted space around it?
    This may be a bit of a nitpick, but generally speaking you cannot get a photo of distorted space, because you cannot get a photo of space. Photos only record photons (in whatever part of the EM spectrum), so the best you can do is get a picture of its effect on photons. That's generally how we know where they are, from either gravitational lensing (which affects photons) or the effect on nearby stars and gas clouds (which emit photons).
    As above, so below

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    Guess I have been mislead by artist renditions of black holes...

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    Quote Originally Posted by gzhpcu View Post
    Guess I have been mislead by artist renditions of black holes...
    I think this one was created for a movie with the assistance of Kip Thorne:

    interstellarwormhole.png

    it would still be pretty small at a few light-years distance.
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    I just watched a new 2-hour episode of NOVA on black holes early
    this morning. Rather elementary, but having 2 hours, they were able
    to cover quite a lot of territory. The history of how black holes were
    theorized and discovered was the main thread. It goes up through
    the observation of gravitational waves from colliding black holes
    with LIGO.

    -- Jeff, in Minneapolis
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

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