"Images" from the edge of a black hole


20 Responses to “"Images" from the edge of a black hole”

  1. Gyrofrog says:

    I’ve seen a black hole, lots of times.  You can see it, too. Plenty goes in but nothing really ever seems to come out of it.

  2. doc w says:

    Hmmmm… A black hole by definition cannot be observed as no light can exit it.  We can only observe the effect of the BH on  matter.

  3. microcars says:

    Ce n’est pas un commentaire

  4. Antinous / Moderator says:

    So black holes look like 70s discos.

  5. Yep says:

    “Enhance… enhance…. enhance… hold.  Just as I suspected. It’s filled with baby pigeons.

  6. Sirkowski says:

    Why did the government edit out the Cylon Colony?

  7. nixiebunny says:

    Whee! I work on one of those telescopes, the HHSMT on Mt. Graham.  It’s a blast.

  8. Phanatic says:

    “Telescopes — the kind we point at deep space — don’t collect images, they collect information.”

    Digital cameras – the kind we point at each other here on Earth every day – don’t collect images, they collect information.  Photons pass through the lens, pass through a filter which separates the incoming light into red, blue, and green wavelengths, and the red, blue, or green light strikes pixels, generating an electrical impulse which is converted into digital value corresponding to how much light struck each pixel. 

    With a radio telescope, photons at radio wavelengths strike an antenna, generating an electrical impulse, which is amplified and converted into a digital value corresponding to how much struck the antenna. 

    So I guess what I’m saying is I’m curious as to what distinction you’re trying to make here.  Even film cameras don’t collect images, the collect information about what grains of silver halide crystals were struck by how much light, there’s no image there until you take the film and do a lot of stuff to it, just like there’s no image from a digital camera or radio telescope until you take the recorded data and do a lot of stuff to it. 

    • nixiebunny says:

       The radio telescopes in question capture identical radio signals from a distant point in the galaxy. Each telescope records the radio signal at a rate of a gigabyte per second onto hard disks, using a hydrogen maser as a time base. The signals are then shipped on hard drives to a correlator facility, which compares the signal waveforms to each other, looking for a point in time where they match each other nearly perfectly. Then the differences between the two waveforms represent interference fringes, which occur over milli-arc-second angle changes. This allows the system to take incredibly high-resolution images of a sort.

      Compare *that* to your digital camera.

  9. AJE says:

    “Telescopes — the kind we point at deep space — don’t collect images, they collect information.”
    Don’t tell Hubble, I still want a few more years of its information.

  10. barn_the_bunny says:

    want to know more about seeing black holes?
    why not listen?
    here’s a titanium physicists podcast episode about detecting black holes in various ways:

    here’s a titanium physicists podcast about quazars

    happy birthday

  11. nixiebunny says:

    Here’s the VLBI hard disk data storage system. These disk packs are mailed to Virginia to get correlated.

    The submillimeter telescope that I work on is here:

  12. Jewels Vern says:

    Yes, it seems that observations, tests, and theories have been almost completely replaced by assumptions, models, and consensus of opinions. 

  13. Anarcissie says:

    Black Holes seem somewhat self-contradictory to me.  If nothing can escape from the Black Hole, then I don’t see how gravity can escape from it, either.  In effect, the mass would dig a hole in spacetime and pull the hole in after it.  It would, in effect, cease to exist in the universe, and we could not observe it in any way.

    • DewiMorgan says:

      I know nothing, but I kind of agree with you. I think.

      If you put a *really* heavy marble on a taut (but infinitely stretchy) rubber sheet, it will pull the sides of its depression down until, near the marble, the sides are vertical.

      There’s no way you can flick another ball horizontally along the sheet in such a way that it would roll down the curve of the sheet, hit the heavy marble and bounce back out: anything you flick into that area of vertical walls will just never come out.

      So obviously, there’s a certain distance from that hole where stuff you flick can come out (somewhat deflected by the curvature of the rubber sheet), and any closer, it won’t come back, and instead will fall down the hole. The “Event Horizon” of the vertically-walled “singularity”.

      A concentration of gravity can’t suck in all the gravity. If gravity is just the curvature of spacetime, it seems obvious that a really large curvature in the rubber sheet can’t make the curvature of the rubber sheet become zero.

      Except… what happens if the heavy marble is really infinitely heavy? The vertical walls get really long. Infinitely long. And the tube narrows even smaller than the marble. What happens if, then, where the tube’s size becomes zero, the rubber snaps? The marble is then in its own separate micro-universe, and the curvature of the sheet where it used to be connected, springs back to zero.

      Can the fabric of spacetime snap? I dunno.

      • Anarcissie says:

         A physicist, given this question, told me that black holes were a permanent distortion of spacetime, apparently not mediated by anything like particles.  However, I don’t know how we know this. I think observations and experimental evidence is needed.  Of course, I’m not a physicist, so I may not know what I’m talking about.

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