Posted on 07/14/2021 11:21:05 PM PDT by LibWhacker
12 July 2021
In the vicinity of black holes, space is so warped that even light rays may curve around them several times. This phenomenon may enable us to see multiple versions of the same thing. While this has been known for decades, only now do we have an exact, mathematical expression, thanks to Albert Sneppen, student at the Niels Bohr Institute. The result, which even is more useful in realistic black holes, has just been published in the journal Scientific Reports.
A disk of glowing gas swirls into the black hole "Gargantua" from the movie Interstellar. Because space curves around the black hole, it is possible to look round its far side and see the part of the gas disk that would otherwise be hidden by the hole. Our understanding of this mechanism has now been increased by Danish master's student at NBI, Albert Sneppen (credit: interstellar.wiki/CC BY-NC License). You have probably heard of black holes — the marvelous lumps of gravity from which not even light can escape. You may also have heard that space itself and even time behave oddly near black holes; space is warped.
In the vicinity of a black hole, space curves so much that light rays are deflected, and very nearby light can be deflected so much that it travels several times around the black hole. Hence, when we observe a distant background galaxy (or some other celestial body), we may be lucky to see the same image of the galaxy multiple times, albeit more and more distorted.
The mechanism is shown on the figure below: A distant galaxy shines in all directions — some of its light comes close to the black hole and is lightly deflected; some light comes even closer and circumvolves the hole a single time before escaping down to us, and so on. Looking near the black hole, we see more and more versions of the same galaxy, the closer to the edge of the hole we are looking.
Light from the background galaxy circles a black hole an increasing number of times, the closer it passes the hole, and we therefore see the same galaxy in several directions (credit: Peter Laursen).
How much closer to the black hole do you have to look from one image to see the next image? The result has been known for over 40 years, and is some 500 times (for the math aficionados, it is more accurately the "exponential function of two pi", written e2π).
Calculating this is so complicated that, until recently, we had not yet developed a mathematical and physical intuition as to why it happens to be this exact factor. But using some clever, mathematical tricks, master's student Albert Sneppen from the Cosmic Dawn Center — a basic research center under both the Niels Bohr Institute and DTU Space — has now succeeded in proving why.
“There is something fantastically beautiful in now understanding why the images repeat themselves in such an elegant way. On top of that, it provides new opportunities to test our understanding of gravity and black holes,” Albert Sneppen clarifies.
Proving something mathematically is not only satisfying in itself; indeed, it brings us closer to an understanding of this marvelous phenomenon. The factor "500" follows directly from how black holes and gravity work, so the repetitions of the images now become a way to examine and test gravity.
As a completely new feature, Sneppen's method can also be generalized to apply not only to "trivial" black holes, but also to black holes that rotate. Which, in fact, they all do.
The situation seen "face-on", i.e. how we would actually observe it from Earth. The extra images of the galaxy become increasingly squeezed and distorted, the closer we look at the black hole (credit: Peter Laursen).
"It turns out that when the it rotates really fast, you no longer have to get closer to the black hole by a factor 500, but significantly less. In fact, each image is now only 50, or 5, or even down to just 2 times closer to the edge of the black hole", explains Albert Sneppen.
Having to look 500 times closer to the black hole for each new image, means that the images are quickly "squeezed" into one annular image, as seen in the figure on the right. In practice, the many images will be difficult to observe. But when black holes rotate, there is more room for the "extra" images, so we can hope to confirm the theory observationally in a not-too-distant future. In this way, we can learn about not just black holes, but also the galaxies behind them:
The travel time of the light increases, the more times it has to go around the black hole, so the images become increasingly "delayed". If, for example, a star explodes as a supernova in a background galaxy, one would be able to see this explosion again and again.
Albert Sneppen's article has just been accepted for publication in the journal Scientific Reports, and can be read here: Divergent reflections around the photon sphere of a black hole.
Translation... “gange rundt” means ‘times around’
Believe it or not, I figured that out.
There’s that term again, “black holes”. Didn’t the writer get the memo:That’s a racist term.
sorte huller
Everything goes around Stacey Abrams many times just to get by her.
Moibus Strip depicted by Escher.
Could astronomic equations be “patented” as a theoretic property of this student, or anyone?
Other things, such as tomes of fiction or pieces of music can be attributed to a particular source.
My 19yo nephew in the Philippines is in engineer college and just the other night I cammed him how to take a strip of paper to form first a loop, then the Mobius loop ...
I watched him as he wrote down the name August Fernand Mobius ... I could see his excitement.
I have taken great pleasure through the years illustrating the Mobius loop to kids.
Something clicks in about 40% of their faces
It seems the text of this article came too close to a black hole then...
No. Mathematical methods and scientific theories are two of a number of things expressly excluded from patentability by every patent code on earth.
Too bad. It seems a shame this student cannot use his inate brain power in some directly lucrative way.
Perhaps he will be invited to become part of a research group. A version of NASA. That CEO for Tesla may also need such a person on their team.
There’s nothing like the universe to bring you down to earth!
No.
Or anyone?
That's tougher. Have to ask the legal minds here. But I don't think so. If you invent something as a result of some equations you've derived, I think only the device you've invented (not the equations) is protected. So someone could take your equations and fly with them; i.e., develop them further, and invent something based on them that's completely different than your original device, if you had one, and you've got no recourse.
Also, if you invent something the government wants (anything to do with encryption, weapons, etc.), they can shut you down completely. You can't publish your results or manufacture anything that incorporates your ideas without their approval. Don't worry. I think they are pretty good about giving discoverers, inventors, etc., a nice little cut or a nice little contract, to manufacture things that have to do with national security. Anyone would love to be in such a position.
Again, this is a math major, definitely not a lawyer, speaking.
Think of the potential of seeing back in time by viewing the same point or stellar object at multiple intervals.
Well, if he’s as smart as it seems he is, there’s nothing to stop him from inventing stuff that actually is patentable.
I think he’ll do OK.
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