Scientists find a new way to see inside black holes

June 15, 2016, Towson University
This computer-simulated image shows a supermassive black hole at the core of a galaxy. The black region in the center represents the black hole's event horizon, where no light can escape the massive object's gravitational grip. The black hole's powerful gravity distorts space around it like a funhouse mirror. Light from background stars is stretched and smeared as the stars skim by the black hole. Credit: NASA, ESA, and D. Coe, J. Anderson, and R. van der Marel (STScI)

Scientists at Towson University and the Johns Hopkins University are reporting a new way to peer through the event horizons around black holes and visualize what lies beneath. Their results could rewrite conventional ideas about the internal structure of spinning black holes. Current approaches use special coordinate systems in which this structure appears quite simple, but quantities that depend on an observer's choice of coordinates can give a distorted view of reality, as anyone knows who has compared the size of Greenland and the USA on a map.

The new approach focuses exclusively on mathematical quantities known as invariants, which have the same value for any choice of coordinates. Expressed in terms of these quantities, black hole interiors reveal a much more intricate and complicated structure than usually thought, with wild variations in curvature from place to place.

These new findings are timely for two reasons, according to Towson University's Kielan Wilcomb, who presented the team's results yesterday at the 228th meeting of the American Astronomical Society in San Diego. First, 2016 is the centennial year of the publication of the theory that first predicted the existence of black holes: Einstein's general theory of relativity. Second, the existence of these objects is no longer a matter of theory, but observational fact. Last September astronomers at the LIGO gravitational-wave observatory detected the first ripples in spacetime from a collision between giant black holes in a distant galaxy.

But while we now know they exist, we will never be able to look inside them, notes team member James Overduin, also of Towson University, since no information can emerge from beyond a black hole's event horizon. Their interiors are, by definition, places that can only be explored mathematically. The new results are thus important in a unique sense. Scientists usually observe first, and then attempt to classify and understand their observations using theory. With black holes this usual course of discovery is reversed: we have a satisfactory theory, but are still groping for the best way to visualize it.

The physical significance of the curvature invariants calculated by Wilcomb, Overduin and Richard C. Henry of the Johns Hopkins University is not yet clear. For the most general black holes (those with mass, spin and electric charge) there are seventeen of these quantities altogether, but they can be related to each other mathematically so that only five are truly independent. Explicit mathematical expressions for some are presented here for the first time. The simplest, known as the Ricci scalar, lies at the heart of general relativity theory. Another, the Weyl invariant, plays an analogous role in one of the few serious alternatives to Einstein's theory, known as conformal gravity. For black holes with no (as expected for the vast majority of real, astrophysical black holes, since they will tend to neutralize themselves with time) this invariant is equivalent to another quantity known as the Kretschmann scalar.

The team's results confirm that the wild fluctuations in the value of this quantity near the singularity inside a spinning black hole include regions of negative curvature, which are associated physically with a phenomenon known as gravitomagnetism (the gravitational analog of ordinary magnetism). Gravitomagnetic fields, fed by rotational energy, are believed to be responsible for generating the tremendous jets which emanate from the poles of supermassive at the centers of some galaxies. A clearer map of curvature inside the horizon, Henry emphasizes, could enable astronomers to understand why such jets exist in some galaxies and not others (including our own).

Explore further: Did gravitational wave detector find dark matter?

More information: "A New Way to See Inside Black Holes," R. C. Henry, J. M. Overduin & K. Wilcomb, 2015, Bridges Baltimore 2015: Mathematics, Music, Art, Architecture, Culture (Phoenix, AZ: Tessellations Publishing, 2015) and presented at the 228th meeting of the American Astronomical Society in San Diego, Calif. aas.org/meetings/aas228, Arxiv: arxiv.org/abs/1512.02762

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HeloMenelo
3 / 5 (4) Jun 16, 2016
sucks knowing that we can't get into it and see if it leads anywhere or what's inside it
antialias_physorg
4.6 / 5 (11) Jun 16, 2016
sucks knowing that we can't get into it and see if it leads anywhere or what's inside it

You never know. By the time we actually can get to a black hole (which is - positing that speed of light can't be broken or circumvented - at least 6k years in the future) we migh t also may know how to create local anti-gravity (since negative energy is already something that can be created (cf. Casimir Force) anti gravity 'could' be possible)

...which might allow a probe at least to push back (loacally) the event horizon and get closer...or even enter, switch the antigrav off for a tiny amount of time to get some measurements, and then reengage it to exit.

Granted there's a lot of might, could, maybe, possibly in this. But I think in the next 6k years we'll come up with some interesting stuff (if we don't hit a wall of one kind or another).
Da Schneib
4.6 / 5 (10) Jun 16, 2016
The AdS/CFT duality is slowly making its way into mainstream physics, and with it comes string physics. Its enormous mathematical complexity is making progress very slow, but the longer we look at it, the more interesting problems it solves. We now have dS/CFT, Kerr/CFT (applicable to this article), and Weyl comformal gravity entering into the picture. I expect this is where physics will eventually discover quantum gravity, and I don't expect it will be anything like as easy to understand as either relativity or quantum mechanics.

[contd]
Da Schneib
4.6 / 5 (10) Jun 16, 2016
[contd]
Similarly, gravitoelectromagnetism is being slowly integrated into gravity physics, which was inevitable from the POV of anyone who is aware that magnetism is the relativistic correction for the action of the electric field; gravity must inevitably have such a correction as well since it propagates at finite speed, and therefore there must be gravitomagnetic effects analogous to the magnetic effects in Maxwell field theory. Gravity Probe B actually measured two of these effects, geodetic and frame-dragging precession. http://apod.nasa....510.html

Gravitomagnetism is, BTW, an important part of the explanation for the "jets" seen around supermassive black holes driving quasars. This is often misunderstood in popular science articles regarding these jets; they are not purely EM phenomena due to the charges in the plasma, but also due to the effects of geodetic and frame dragging precession on particles in the ergosphere of the black hole.
Da Schneib
4.6 / 5 (10) Jun 16, 2016
Continuing along these lines, it is possible that the dividing line between galaxies that have jets and behave like quasars, and galaxies that do not, is the amount of spin of the central SMBH. The interesting question in this case is why some galaxies that have SMBHs with high spin and some with low exist, and why in that case SMBHs lose their spin over time as the absorb matter, thus ending the so-called "era of quasars." However this is rank speculation and should be taken as such; I am not facile enough with the AdS/CFT correspondence, or with CFTs in general, to have a strong opinion here.
Chris_Reeve
Jun 16, 2016
This comment has been removed by a moderator.
Benni
1.9 / 5 (9) Jun 16, 2016
First, 2016 is the centennial year of the publication of the theory that first predicted the existence of black holes
.....I've studied General Relativity very closely & am still looking for the section supporting this claim not only by this Author but anyone who parrots this tripe. Einstein in fact denied such gravity wells could exist. Could somebody provide a lead-in highlight for this section?

The black region in the center represents the black hole's event horizon, where no light can escape the massive object's gravitational grip.
.........oh just great, now information (photons) is lost not only at the BH surface but also at the so-called Event Horizon. It used to be that only particles lost escape velocity upon entering the Event Horizon, but now they are claiming so also do photons lose Escape Velocity in that area. Or.......does this Author think the EH & BH Surface are the same thing? No wonder Einstein was astute in debunking the BH process.

Benni
1.9 / 5 (9) Jun 16, 2016
I am not facile enough with the AdS/CFT correspondence, or with CFTs in general, to have a strong opinion here.
...........then why did you bother Schneibo, along with everything else you posted it's unintelligible in the first place.

You come here wanting the gullible to believe you are some kind of New Age Pop-Sci genius, but you can't even point to the section of Einstein's General Relativity that supposedly predicts the existence of Black Holes. So what's the Title of the section of GR prediction for the existence of BHs?

Copy & Paste for us the first few lead-in sentences in General Relativity so we can know exactly where to start reading all about BHs within GR. Maybe you think it's the Photon Deflection section? I've studied it, nothing about infinite BH gravity wells there. So where is it?

Da Schneib
3.9 / 5 (11) Jun 16, 2016
Quoth @bshott
Hey geniuses, if the internal structure of the hypothetical object "varied wildly in curvature", the event horizon wouldn't be spherical as said variants must affect the internal space all the way out to it.
Apparently you didn't read the article very well; these varying curvatures cancel one another to yield the event horizon we see from outside. And we're not talking about a Schwartzchild BH here; this is a Kerr (spinning) BH. Astrophysicists don't expect to see many Reissner–Nordström or Kerr-Newman BHs since they don't expect to see BHs with a net electric charge. You might even want to actually read the paper (no paywall) if you really want to understand what they're saying.

Please try to think of the ramifications of math that is supposed to describe a physical reality instead of just slobbering over it.
We can figure out the math, apparently it's you who can't. Stop projecting.
Da Schneib
3.8 / 5 (10) Jun 16, 2016
The problem is that black holes are such a squishy concept
They're valid solutions to the EFE (and the Maxwell equations, too, in the cases of RN and KN BHs). I don't particularly find solutions to GRT to be "squishy," any more than I find solutions to most equations to be "squishy." Eliminating "squishiness" is what math is all about. I can think of a lot of things to say about math, but "squishy" isn't one of them.
Da Schneib
3.8 / 5 (10) Jun 16, 2016
then why did you bother Schneibo, along with everything else you posted it's unintelligible in the first place.
Well, unintelligible to you anyway. But that's not anything I'm overly concerned with.

you can't even point to the section of Einstein's General Relativity that supposedly predicts the existence of Black Holes
GRT isn't solutions; it's equations. Not to mention for someone who claims to know what DEs are it's kinda revealing to fail to understand the difference.

You just showed you don't even know what GRT is in the first place, so this is just playgrounding.
Da Schneib
3.9 / 5 (11) Jun 16, 2016
we migh t also may know how to create local anti-gravity (since negative energy is already something that can be created (cf. Casimir Force) anti gravity 'could' be possible)
Antigravity is gravity; you just create an equal and opposite field at every point of interest. Now, how you do that is the real kicker... for a perfect antigravity field to a BH's, you'd need another BH of the same mass and spin (and charge, if it has any). Of course, you could cheat a bit since you don't have to precisely match the target BH's effect except over the extent of your vehicle; this might let you use a smaller BH, but nothing else we know of is dense enough to do it.

[contd]
Da Schneib
3.9 / 5 (11) Jun 16, 2016
[contd]
which might allow a probe at least to push back (loacally) the event horizon and get closer...or even enter, switch the antigrav off for a tiny amount of time to get some measurements, and then reengage it to exit.
Another more interesting dodge is to enter the ergosphere outside the technical event horizon. Since most astronomical BHs (particularly stellar ones) must have spin, this is a definite possibility; all spinning BHs have an ergosphere.

Granted there's a lot of might, could, maybe, possibly in this. But I think in the next 6k years we'll come up with some interesting stuff (if we don't hit a wall of one kind or another).
I agree. Fun speculation; thanks!
Benni
1.9 / 5 (9) Jun 16, 2016
Schneibo, you can't even point to the section of Einstein's General Relativity that supposedly predicts the existence of Black Holes


GRT isn't solutions
......the author disagrees with you, he states GR predicts the existence of BHs. Are you smarter than the Author?

it's equations
OK Schneibo, then Copy & Paste the equations that the Author claims predicts BHs.

Not to mention for someone who claims to know what DEs are it's kinda revealing to fail to understand the difference
.......well then, let's just see if you can recognize enough of those DEs to point us to those "equations" in the Photon Deflection section of GR by which you & the author claims Einstein did the "equations" to predict the existence of BHs.


Da Schneib
4.2 / 5 (10) Jun 16, 2016
the author disagrees with you, he states GR predicts the existence of BHs. Are you smarter than the Author?
That's a popular science author being a little fuzzy about terminology. If you have a problem with it I suggest you let him know. I expect he'll ignore you. Maybe you can tell him what an expert you are with DEs.

OK Schneibo, then Copy & Paste the equations that the Author claims predicts BHs.
I already told you that it's a solution to GRT that predicts BHs. You brought up a semantic quibble about terminology in a pop science article and I've dealt with that as well. To top it all off you know perfectly well that Schwarzchild found the solution, so there's nowhere in the EFE to find it. You're just playgrounding. It's a sorry thing to see a grown human do.

Photon Deflection section of GR
There isn't any "Photon Deflection section of GR." Now you're just making stuff up.
antialias_physorg
4.6 / 5 (9) Jun 17, 2016
Antigravity is gravity;

Sorta. If we look at gravity as warping of space then two sources opposite a 'probe' will nullify. But a source and an anti-source on the same side of the probe would also nullify. As you point out if one of the sources (or the anti-source) is much closer than the other source then it can be weaker and still lead to local zero gravity for the 'probe'.

An anti-source requires negative energy* (though currently we can't create that without having more of the regular kind close by...so not yet usable for the effect on a macroscopic scale..and alos nowhere near the required amount. But if one could separate the two components spatially there may be a way to have a local antigravity field at the expense of another, local positive gravity field nearby)

*
https://bruceleee...-to-lab/
(see section "Generating Negative Energy in Lab"...particularly squeezed states)
Da Schneib
4.1 / 5 (9) Jun 17, 2016
@antialias Meh, I'd have to see an experiment show segregated negative energy. Until that happens I have serious doubts it's possible macroscopically; I suspect it may not be possible even at the smallest lengths/highest energies we can probe, though I'd've said the same thing about a negative index of refraction, and they've done that with condensed matter. I'm not on the fence; I don't think negative energy is possible. But I don't rule it out completely.

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