Speeding Stars Confirm Bizarre Nature of Faraway Galaxies

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physicsguy

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Clara Moskowitz
Staff Writer
SPACE.com clara Moskowitz
staff Writer
space.com – Wed Aug 5, 1:16 pm ET
Stars in a distant galaxy move at stunning speeds — greater than 1 million mph, astronomers have revealed.


These hyperactive stars move at about twice the speed of our sun through the Milky Way, because their host galaxy is very massive, yet strangely compact. The scene, which has theorists baffled, is 11 billion light-years away. It is the first time motions of individual stars have been measured in a galaxy so distant.


While the stars' swiftness is notable, stars in other galaxies have been observed to travel at similarly high speeds. In those situations, it was usually because they were interlopers from outside, or circling close to a black hole.


But in this case, the stars' high velocities help astronomers confirm that the galaxy they belong to really is as massive as earlier data suggested.


Bizarre, indeed


The compact nature of this and similar galaxies in the faraway early universe is puzzling to scientists, who don't yet understand why some young, massive galaxies are about five times smaller than their counterparts today.


"A lot of people were thinking we had overestimated these masses in the past," said Yale University astronomer Pieter van Dokkum, leader of the new study. "But this confirms they are extremely massive for their size. These galaxies are indeed as bizarre as we thought they were."


Scientists used the new velocity measurements, conducted with the Gemini South telescope in Chile and the Hubble Space Telescope, to test the mass of a galaxy identified as 1255-0. The same way that the sun's gravity determines the orbiting speed of the Earth, the galaxy's gravity, and thus its mass, determines the velocities of the stars inside it.


The researchers found that indeed, the galaxy is exceptionally dense.


Given its distance of 11 billion light-years, galaxy 1255-0 is seen as it existed 11 billion years ago, less than 3 billion years after the theoretical Big Bang. Among other galaxies we can observe from this time period, about 30 to 40 percent are compact like this one. But in the modern, nearby universe, astronomers don't find anything similar.


Something wrong?


Somehow, high-mass galaxies from the young universe grow in size but not in mass – they spread out but maintain their overall heft – to become the high-mass galaxies we see today.


"It's a bit of a puzzle," van Dokkum told SPACE.com. "We think these galaxies must grow through collisions with other galaxies. The weird thing is that these mergers must lead to galaxies that are larger in size but not much more massive. We need a mechanism that grows them in size but not in mass."


So far, such a mechanism is elusive, but astronomers have some ideas. Perhaps these galaxies expand their girth by merging with many small, low-mass galaxies. Or maybe these galaxies eventually become the dense central regions of even larger galaxies.


"It could also still be that we are doing something wrong," van Dokkum said. "But I think at the moment you could say that the ball is somewhat in the court of the theorists. Hopefully they can come up with some kind of explanation that we can test further."

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Original Story: Speeding Stars Confirm Bizarre Nature of Faraway Galaxies
 
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physicsguy

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Sounds more like Black Holes have a way of becoming less massive over time. Possibly by their magnetic fields interacting with other stars and gases, neutrino loss, the unfolding of space-time itself or some combination. Hopefully some theoretical physicist will read this, figure out the math portion and find a way to prove the theory. It would explain a lot since the Big Bang implies that our universe originated from a super massive black hole.

This would also suggest that the universe may go through cycles of collapsing and expanding on many levels, and the universe may be infinitely older than we think it is. The idea that the universe is infinitely old and non-causal is actually supported by modern physics. Causality and time as we experience it exists in pockets throughout the universe. We can visualize them by seeing how super massive stars and galactic centers bend time and space. Within these pockets we see A leading to B, and then B leading to C, but an outside observer would see A, B and C occuring simultaneously. A, B and C are events in the past, present and future.

Graphically, if you visualize space-time being bent infinitely by any black hole and flatten it vertically, then you would have an infinite amount of time and space to fill up the universe. Black holes can be created by localizing mass and in this way, so can energy and mass from a relative point of view. One thing that eludes modern science is where all the mass and energy came from in the first place and I think this is a reasonable explaination. Maybe not the right one, but without ideas and people not afraid to share them for the common good, we would still be living in huts.

Daniel Nase
 
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ramparts

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physicsguy":1kbv6cjv said:
Hopefully some theoretical physicist will read this, figure out the math portion and find a way to prove the theory.
Sorry, buddy, that's not how it works :) It takes a lot more for a good theory to be developed than to simply take an interesting idea and "put it in math." There are a lot of restrictions on what the universe can and can't do, and all theories have to fit within that. In this particular case, there is absolutely no way we know of, in any theory, for black holes to lose mass. That's why they're black - nothing can escape! So if you want theoretical physicists to take up that idea, they'd first need to rewrite all of modern physics just to find a mechanism for black holes to lose mass. That idea makes no sense given what we know about the universe, and there are far better explanations for this particular result of galactic astronomy, so there's not much motivation to go out and change physics just to "figure out the math portion" :D

Just one more thing (for one's enlightenment): even ignoring all the other issues with this idea, black holes losing mass wouldn't explain how galaxies grow in size but not so much in mass. The supermassive black holes at the centers of galaxies are super massive, yes, but pretty lightweight compared to the rest of the galaxy - there's still billions of stars to account for! The most massive central black holes are less than 1/100 of the total galaxy's mass, and most are far lighter. Even if the black holes disappeared, that wouldn't be the answer ;)
 
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alfa_georgios

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It's just the evolution procedure.
In the young galaxies, the black holes are exchanging matter, 'sucking' the detectible to us matter, giving back undetectible matter, the so called 'black matter', it's radiation only, due to it's 'struggle to escape' the black hole's boundaries, can be detected, which is the cause, 'the feedstock' of the new stars birth. Thus the younger galaxies are gaining in size but not much in mass.
During this procedure it comes the time the 'production' of the 'black matter' is so immense that the black hole collapses, an analogical phenomenon to a super nova's explosion, or to be better understood, is like turning a glove inside-out. Then these new small in girth, huge in mass galaxies are formed, having in their core 'black matter' in such a density parallel to the density of a black hole's core and instead a black hole's gravity, an analogical extruding force, spreading out numerous stars in the speed similar to a star's speed 'trapped' by a black hole.
 
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alfa_georgios

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just forgot to add, that's why the universe will for ever be expanding accelerated...
 
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physicsguy

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Sorry, buddy, that's not how it works :) It takes a lot more for a good theory to be developed than to simply take an interesting idea and "put it in math." There are a lot of restrictions on what the universe can and can't do, and all theories have to fit within that. In this particular case, there is absolutely no way we know of, in any theory, for black holes to lose mass. That's why they're black - nothing can escape! So if you want theoretical physicists to take up that idea, they'd first need to rewrite all of modern physics just to find a mechanism for black holes to lose mass. That idea makes no sense given what we know about the universe, and there are far better explanations for this particular result of galactic astronomy, so there's not much motivation to go out and change physics just to "figure out the math portion" :D
Well if black holes are soo black, then how do neutrinos escape? :)

Magnetic fields interact: When a black hole spins, its magnetic field interacts with the galaxy creating X-rays. That means either the black hole is transfering energy to the surrounding galaxy or they are being magically created lol. :p In addition, secondary magnetic fields are created in the surrounding galaxy that interact with the black hole.
 
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ramparts

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physicsguy":sbp9suk9 said:
Sorry, buddy, that's not how it works :) It takes a lot more for a good theory to be developed than to simply take an interesting idea and "put it in math." There are a lot of restrictions on what the universe can and can't do, and all theories have to fit within that. In this particular case, there is absolutely no way we know of, in any theory, for black holes to lose mass. That's why they're black - nothing can escape! So if you want theoretical physicists to take up that idea, they'd first need to rewrite all of modern physics just to find a mechanism for black holes to lose mass. That idea makes no sense given what we know about the universe, and there are far better explanations for this particular result of galactic astronomy, so there's not much motivation to go out and change physics just to "figure out the math portion" :D
Well if black holes are soo black, then how do neutrinos escape? :)
For the same reason people escape - they don't.
 
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darkmatter4brains

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Hawking radiation is supposed to make a black hole lose mass.

Although, I don't know what the current consensus is on this.

http://en.wikipedia.org/wiki/Hawking_radiation

An excerpt:

"A slightly more precise, but still much simplified, view of the process is that vacuum fluctuations cause a particle-antiparticle pair to appear close to the event horizon of a black hole. One of the pair falls into the black hole whilst the other escapes. In order to preserve total energy, the particle that fell into the black hole must have had a negative energy (with respect to an observer far away from the black hole). By this process, the black hole loses mass, and, to an outside observer, it would appear that the black hole has just emitted a particle. In reality, the process is a quantum tunneling effect, whereby particle-antiparticle pairs will form from the vacuum, and one will tunnel outside the event horizon."

That whole negative energy thing bothers me. The Dirac equation comes out with two solutions - one seemingly a negative energy state and the other a positive energy state. This was originally interpreted by Dirac via the negative energy "sea of electrons". However, it was later interpreted by Feynman essentially as a particle running backwards in time! :shock: Either way, the supposed negative energy solution is interpreted as an antiparticle with positive energy. This is the matter/antimatter symmetry that comes out of the Dirac equation. Anyhow, an actual negative energy state would have been bad news here ....

BUT, now these virtual particles in Hawking radiation are allowed to have negative energy??

Can anybody fill in the details here?
 
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darkmatter4brains

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On second thought, the Dirac equation as mentioned above is dealing with free particles, which should have positive energy solutions.

Negative energy states can, and do, exist in bound states. (e.g. -13.6eV for an electron in the ground state of an Hydrogen atom)

Is the originally "free" virtual particle, once captured by the Black Hole, then viewed as a bound state, between itself and the black hole?? Meanwhile, the one that escaped is a free particle with a positive energy state. And, energy is then conserved in the process as well.

I guess ...
 
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ramparts

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The "virtual particle" way of looking at Hawking radiation is an analogy at best. I don't know for sure but I'd imagine you're probably taking it a step too far :) Maybe not. darkmatter, I think you know enough to get a lot out of Hawking's original paper - certainly more than I could! :lol: I just read it this weekend, taking in what I could. Not a bad read at all, compared to many more recent papers.

Anywho, we certainly expect black holes to radiate away mass via Hawking radiation, and there is to the best of my knowledge no major trend in theory suggesting otherwise. Of course, such a thing has yet to be observed ;)
 
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darkmatter4brains

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You're most likely right - I definitely wouldn't be surprised if I was reading too much into it. A lot of these theories have so many subtle details, it's real easy to get off track on your thinking about them. I've always liked the phrase, "I know just enough to be dangerous" :)

Thanks for the tip on the article! I'll have to try an attempt at reading it. I kinda doubt I will get too much out of it, but sounds like an interesting read.

That idea (Hawking radiation) is one that has always bugged me for one reason or another - all due to not fully understanding it I'm sure. But, those so-called "virtual" particles would have to become real, I think, if they couldn't annihilate themselves thanks to the Black Hole. And, if they did become real, in order to avoid energy conservation violations it seems like the whole negative energy thing for the one is inescapable. But, from my understanding, a negative energy "free" particle would be bad news. Anyhow, hopefully, Hawkings paper will help me out!

Seems like a hard thing to observe too! If I remember correctly the radiation is pretty miniscule. I don't remember the mass of the black hole, but I thought in one example, they said it would take 10^100 years for it to fully evaporate. That's a long time!! Plus, don't all the black holes we've found so far have accertion disks, which I believe would totally swamp out the Hawking Radiation? I think it would be awfully hard to find a Black Hole that's not devouring some matter!
 
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ramparts

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darkmatter4brains":1fkrpz49 said:
You're most likely right - I definitely wouldn't be surprised if I was reading too much into it. A lot of these theories have so many subtle details, it's real easy to get off track on your thinking about them. I've always liked the phrase, "I know just enough to be dangerous" :)

Thanks for the tip on the article! I'll have to try an attempt at reading it. I kinda doubt I will get too much out of it, but sounds like an interesting read.

That idea (Hawking radiation) is one that has always bugged me for one reason or another - all due to not fully understanding it I'm sure. But, those so-called "virtual" particles would have to become real, I think, if they couldn't annihilate themselves thanks to the Black Hole. And, if they did become real, in order to avoid energy conservation violations it seems like the whole negative energy thing for the one is inescapable. But, from my understanding, a negative energy "free" particle would be bad news. Anyhow, hopefully, Hawkings paper will help me out!
Mmm, here you go: http://www.springerlink.com/content/c4553033029k5wk6/

On page 4: "It should be emphasized that these pictures of the mechanism responsible for the thermal emission and area decrease are heuristic only and should not be taken too literally. It should not be thought unreasonable that a black hole, which is an excited state of the gravitational field, should decay quantum mechanically and that, because of quantum fluctuation of the metric, energy should be able to tunnel out of the potential well of a black hole."

From the mouth of the man himself, lol. Very interesting read.

Seems like a hard thing to observe too! If I remember correctly the radiation is pretty miniscule. I don't remember the mass of the black hole, but I thought in one example, they said it would take 10^100 years for it to fully evaporate.
In fact, I believe I said that, earlier today, in another thread ;)

That's a long time!! Plus, don't all the black holes we've found so far have accertion disks, which I believe would totally swamp out the Hawking Radiation? I think it would be awfully hard to find a Black Hole that's not devouring some matter!
But after even a few tens of billion years, tops, the era of active nuclei will be gone. At that point, the devouring will largely stop except for a few special instances.
 
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darkmatter4brains

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ramparts":13ng927e said:
darkmatter4brains":13ng927e said:
Seems like a hard thing to observe too! If I remember correctly the radiation is pretty miniscule. I don't remember the mass of the black hole, but I thought in one example, they said it would take 10^100 years for it to fully evaporate.
In fact, I believe I said that, earlier today, in another thread ;)
What was the black hole mass? I don't recall it being anything even close to a supermassive black hole?

Thanks for the link on the Hawking article.
 
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kelvinzero

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Somehow, high-mass galaxies from the young universe grow in size but not in mass – they spread out but maintain their overall heft – to become the high-mass galaxies we see today.
I assume it would be way too obvious if it were merely as simple as tidal effects, the same as the way the moon is slowly stealing angular momentum from the earth and increasing the radius of its orbit.
 
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