"Images" from the edge of a black hole

EDIT: This post originally went up with the wrong images. Sorry about that.

This is not a photograph.

But it's still amazing.

An important thing to remember about science is that some of the stuff we talk about in the general public as "fact" — like, say, black holes — haven't actually been seen by anybody. Instead, black holes exist on paper, as part of theoretical astrophysics. They also exist in indirect evidence — we can look for things in the universe that should exist in a certain way, in a certain place, if our theoretical astrophysics is correct. So far, that lines up, too.

And then there's this thing. Like I say, it's not a photo. It's more like a model. Telescopes — the kind we point at deep space — don't collect images, they collect information. This is a digital rendering made based on information collected when researchers pointed four different telescopes at a galaxy called (poetically) galaxy M87. What you're looking at is a series of simulations, over time, showing massive ribbons of gas undulating and spinning around the something at the galaxy's center. If the theoretical astrophysics is right, this is the closest we've ever gotten to seeing a black hole.

Physicist and writer Matthew Francis has a really good explanation of these new images on his blog, Galileo's Pendulum.

New observations from the Event Horizon Telescope (actually an array of four millimeter-wave telescopes working in concert) have revealed the best view so far of the supermassive black hole in the galaxy M87. As described in a Science paper, astronomers measured the motion of gas to a distance approximately 5.5 times the event horizon radius. That is close enough to confirm the gas circles in the same direction the black hole itself rotates. These observations help clarify the origin of the powerful jet of gas streaming from the galaxy’s center at a high fraction of the speed of light: it is likely driven by the swirling matter near the black hole’s boundary.

This is a hard piece to excerpt from, because you really need to read the full thing if you actually want to understand how we think black holes work, and what that tells us about the data collected by those joined-up telescopes.

I recommend reading both Francis' earlier piece explaining some black hole basics, and this new story about the specific paper that published these images and the data they're based on.

But, suffice to say, this is pretty awesome. It's as if we've never been able to observe Niagara Falls and, for the first time, saw the spray of water rising in the air around it. Or, rather, we collected data on the movement of water particles in the air near where we think a theoretical Niagara Falls is and then somebody drew a picture of the particles. It's a little more esoteric than just taking a photo, but it's still worth geeking out over.



      1. Nah, Hawking Radiation would be imperceptible with our current technology, just one fuzzy subatomic particle here and there, every once in a while.

  1. “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. 

    1.  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.

  2. “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.

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

  4. 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.

    1. 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.

      1.  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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