Star Orbiting Massive Black Hole Lends Support To Einstein's Theory (reuters.com) 61
Observations of light coming from a star zipping in orbit around the humongous black hole at the center of our galaxy have provided fresh evidence backing Albert Einstein's 1915 theory of general relativity, astronomers said on Thursday. From a report: Researchers studied a star called S0-2, boasting a mass roughly 10 times larger than the sun, as it travels in an elliptical orbit lasting 16 years around the supermassive black hole called Sagittarius A* residing at the center of the Milky Way 26,000 light years from Earth. They found that the behavior of the star's light as it escaped the extreme gravitational pull exerted by the black hole, with 4 million times the sun's mass, conformed to Einstein's theory's predictions. The famed theoretical physicist proposed the theory, considered one of the pillars of science, to explain the laws of gravity and their relation to other natural forces.
While Einstein's theory held up in the observations of this star, astronomer Andrea Ghez of the University of California, Los Angeles said it may not be able to fully account for what happens in the most exotic possible gravitational environments like those of black holes. These extraordinarily dense celestial entities exert gravitational fields so strong that no matter or light can escape.
While Einstein's theory held up in the observations of this star, astronomer Andrea Ghez of the University of California, Los Angeles said it may not be able to fully account for what happens in the most exotic possible gravitational environments like those of black holes. These extraordinarily dense celestial entities exert gravitational fields so strong that no matter or light can escape.
Fully account for what? (Score:5, Interesting)
[A]stronomer Andrea Ghez of the University of California, Los Angeles said it may not be able to fully account for what happens in the most exotic possible gravitational environments like those of black holes. These extraordinarily dense celestial entities exert gravitational fields so strong that no matter or light can escape.
If no matter, or light, or theory of gravity can escape, then... what point can be proven, exactly?
Re:Fully account for what? (Score:4, Funny)
Unlike a black hole, it is impossible to get information out of a Slashdot summary.
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Re: Fully account for what? (Score:3)
The problem is with the "summary", not with TFA. In the recent months, editors are getting used to posting excerpts of the articles instead of summaries of them. This makes that many articles have no complete sense or no rational discussion. In this case, the apparent conclusion of the summary is the opposite of TFA.
Click air?
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The problem is with the "summary", not with TFA. In the recent months, editors are getting used to posting excerpts of the articles instead of summaries of them. This makes that many articles have no complete sense or no rational discussion. In this case, the apparent conclusion of the summary is the opposite of TFA.
So what? That's where you and I come in.
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If no matter, or light, or theory of gravity can escape, then... what point can be proven, exactly?
Theories are mental constructs and are not included as a variable inside Einstein's theory of General Relativity.
A black hole is so massive that once light is captured, it cannot escape.
What the scientist is saying is that we cannot (yet) predict what takes place inside a black hole.
The Theory goes nuts at depth.
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A prediction of the amount of bending, also doesn't tell you if gravity is the *cause* or *consequence* of the compressed 'space'.
If matter has mass, mass makes gravity, gravity bends space then you have the limit condition and you have a problem making predictions.
Similarly, if matter has mass, and the mass directly bends space (somehow) then you still have the limit condition, and still have the problem.
But if matter has structure, and that structure causes the binding, i.e. tight binding means more bindi
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On any even vaguely "science" story, never waste effort on trying to understand the summary. Find the original paper (here [aanda.org]) and read that - or at the very least least, the abstract.
Abstract :
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If no matter, or light, or theory of gravity can escape, then... what point can be proven, exactly?
There is a theoretical split between quantum mechanics and general relativity. How light interacts with the event horizon could give an idea of what is on and reveal new physics. We think we understand how the light should bend and scatter around the edge of an event horizon depending on which one is more correct. If we could just get a naked event horizon with a light source behind it, we could probably get an answer. I suspect that getting good enough information in real life on such an experiment that is
That's a twist (Score:1)
I had read that theory didn't hold up; there is physics that are not being explained.
Indeed, it seems to be admitted here thinly at the end of the summary:
You know, the Epicycles of Mars are damn good at predicting the location of Mars; ye
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I'm an idiot for ever doubting Einstein even for an instant.
At this point, anyone who doubts General Relativity is an idiot. Same with Newton and his laws of motion. Both are so extremely accurate within their energy and scale ranges that any theory of everything would simplify to these at the same scales. This is proven out by countless experiments and since it explains the data so phenomenally, well - it will never be wrong in any meaningful sense.
There are some arrangements of matter that may not have closed form simple mathematical solutions, like how mult
What's inside the black hole? (Score:1)
If light is the same stuff as matter, then you'd expect it to bend because matter is deflected by gravity, then so must light.
If light is a wave traveling across a medium (somehow that medium is empty space) , then that medium (empty space) needs to bend to bend both light and matter.
Either way, it's clearly not *not* bending, as according to the Newtonian model.
Ghez is just saying it doesn't explain what's inside that black hole. He's not dismissing Einstein, he's simply stating the limits of understanding
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Every experiment done on GR for the last 100 years has confirmed GR. We have working technology based on
Link to the original paper (Score:5, Informative)
Relativistic redshift of the star S0-2 orbiting the Galactic center supermassive black hole [arxiv.org]
Our result, gamma=0.88±0.17, is consistent with General Relativity (gamma=1) and excludes a Newtonian model (gamma=0 ) with a statistical significance of 5 sigma.
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They seem to say that their error margin is ±20%.
That seems pretty wide.
I think there may still be some physics to be discovered.
Re:Link to the original paper (Score:5, Informative)
The size of the error bars says something about how the thing is being measured, not about the underlying theory. Large error bars typically mean that the measurement is tricky and pushing the limits of what we can do.
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But does it bend space? Or is it just bending light?
It bends space itself according to all observations so far. Of corse we kind of define space by the paths particles (mass and massless) take but I'm convinced this may not be the best way to view space. Space itself seems like it's 3-D but compressed onto a 2D surface (like a hologram) with the evidence being how mass and surface area (not volume like in everyday life) of black holes are proportional. So what is obvious to us (and which will never be disproven for our every day scales) may be more effecti
Einstein may be long-dead (Score:3)
But he is still The Man.
Not fully account (Score:2)
Einstein's theory (...) may not be able to fully account for what happens in the most exotic possible gravitational environments like those of black holes.
Did the observations confirmed Einstein theory or not? If they did, why this sentence?
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Re: Not fully account (Score:1)
So the real question is what happens very near the event horizon? Are black holes fuzzy? Is there a maximum mass density? Is there even an event horizon? What we know is black holes behave as predicted from a distance, but there is a lot of speculation about what happens even before you get to the event horizon. If we could somehow observe it you could disprove string theory, for example, because string theory makes predictions about black holes.
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This is an unfortunately common misstatement of black hole physics. charge, momentum, and angular momentum are all measurable. It's difficult if not impossible to get _detailed_ internal information to the outside from the inside, because the escape velocity is beyond the speed of light. But black holes _radiate_, with Hawking radiation, at or near their event horizons, especially if they are small. Unless fed matter, they _evaporate_, exposing their internal structure of any remaining matter. Moreover, i
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To add to that, a black hole will evaporate on the order of trillions of years. And their internal structure isn't what's being exposed. Hawking radiation is one of half of virtual particles created out of nothing near the event horizon of a black hole. One particle gets sucked in, the other is the radiation. (Virtual particles are being created everywhere, not just near black holes.)
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> To add to that, a black hole will evaporate on the order of trillions of years
This depends on the size of the black hole. The larger the hole, the more stable. This was a fascinating discovery, explaining why small black holes that one might expect from the Big Bang are no longer available for detection. A supergalazy size black hole might last 10^106 years, according to the clear article over on Wikipedia.
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Some consistent estimates of the lifespan are less than 10 billion years. That is an American billion, not a UK billion, so that's roughly 10^10 years. If the universe is cyclic or the universe itself is closed, effectively its own black hole, that means all black holes will be subsumed
Theories that the universe itself is a black hole are consistent with the idea that black holes can have internal structure. It's not an exotic state of unimaginable hysics inside a black hole, and there is no logical reason
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Nor does the net gravitational effect of a black hole mean there is no internal structure, especially for a very large black hole
What's so odd is the structure itself appears 2 dimentional. Feed it mass/energy and it grows its surface area by the amount of area that mass/energy would have had as individual particles compressed to black holes (plank length sphere for photons). It's crazy to think everyday stuff dosent fit in a room, but instead fits on a surface and the bigger black holes get the less sense they are - supermassive ones are only as dense as water. Given the density of our universe, it really does kind of look like
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Part of the difficulty is that measuring the internal structure of a black hole from outside that hole is extremely limited. Given this, theorists have enjoyed freedom to invent many otherwise impossible structures such as wormholes. It's also true that, for modest or small holes, the density required to generate them is tremendous and the purely gravitational compression also extreme, so ordinary matter would... well, become as dense as neutron star matter or more.
As I understand the physics, they can also
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Escape (Score:2)
...the supermassive black hole called Sagittarius A* residing at the center of the Milky Way 26,000 light years from Earth. They found that the behavior of the star's light as it escaped the extreme gravitational pull exerted by the black hole...
Gives 'A* pathfinding' a whole new meaning.
Observations != Evidence (Score:1)
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