Gravity waves detected for the first time ever

I was informed by a professional GR theorist a while back that White Holes cannot possibly exist in our Universe. I don't recall now the actual reasons he gave, but one was that WH's would tend to decrease entropy and go against what we know of the law of thermodynamics. In reality they are the time reverse of a BH.

Current explanations for the polar jets that appear to emanate from SMBH's are caused by rotating BH's with tangled magnetic fields.....Matter that is spiralled in from accretion disks are approaching "c" and some of it is literally spun around with the twisted magnetic field lines and then thrown out at the polar regions as we observe.

Speaking of the density of a BH is meaningless due to the fact that all it is is critically curved spacetime, with the mass at the Singularity in the center.
GR informs us that once the Schwarzchild radius is reached, further collapse is compulsory. at least up to the Singularity/quantum/Planck level where GR does not apply being a classical theory.
In essence it is a natural occurrence and aligns with GR that any SMBH will have apparently low densities when the SMBH extends to the EH.

 

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Technically, they don't; the jets are shooting out of the center of the accretion disk, not the black hole. The reason they're there is because the accretion disk is made of plasma, and the plasma, being charged, develops magnetic fields, and traps existing ones. The trapped magnetic fields are then carried closer and closer to the central massive object, and concentrated. The accretion disk also rotates due to its intrinsic momentum (that of the galaxy that surrounds it, which is where the material comes from), and due to conservation of momentum and the laws of orbital mechanics. The combination of the rotation, the concentrated magnetic field, and the plasma is what forms the jets, not the black hole. The gravity from the black hole only drives the process; there's much more to the picture than just that, though.

In fact, many objects that are not black holes also have jets; what they have in common is that they all come from accretion disks. For example, jets have been observed emitting from the centers of accretion disks around T Tauri stars, neutron stars, X-ray binaries, and cataclysmic variable stars. As an example closer to home, Saturn's rings are an example of an accretion disk, although they are not energetic enough to form jets, and the entire Solar System formed from the accretion disk around the nascent Sun. Protostars also form accretion disks; whether, like some T Tauri stars, they are energetic enough to form jets or not varies. X-ray binaries are a particularly interesting case because they are generally a black hole or neutron star that has evolved from one of the pair, sucking gas from the other star because it has evolved into a red giant and its atmosphere has expanded; the compact star sucks gas from the atmosphere, forms an accretion disk, and the disk often forms jets.

So it would be incorrect to state that active galaxies are the only thing that forms these jets, or accretion disks. The reasons that accretion disks around supermassive black holes at the centers of some galaxies have jets are the same reasons that accretion disks around other massive objects have jets.

Errr, nothing there is "the mass of one star." The black holes aren't, the accretion disks aren't, and the jets aren't, at least not in the case of the SMBH at the center of a quasar.

They know there are black holes there because of the paths of stars around them. There's some gravity physics for ya. And lately telescopes have gotten powerful enough that we can see the physics of the accretion disks for some of them, and they confirm the same gravity physics.

Why would a white hole form jets, and why would it have an accretion disk? Seems to me a white hole would have matter flowing out in all directions, not just along the axes, and I can't see how a white hole would form an accretion disk at all.

 

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DP, caused by a reboot, deleted.

 

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The short reason white holes can't exist is because they would require antigravity.

 

http://www.spacedaily.com/reports/N..._pin_down_gravitational_wave_sources_999.html

Fermi telescope poised to pin down gravitational wave sources:

Last year on Sept. 14, waves of energy traveling for more than a billion years gently rattled space-time in the vicinity of Earth. The disturbance, produced by a pair of merging black holes, was captured by the Laser Interferometer Gravitational-Wave Observatory (LIGO) facilities in Hanford, Washington, and Livingston, Louisiana. This event marked the first-ever detection of gravitational waves and opens a new scientific window on how the universe works.

extract:

Less than half a second later, the Gamma-ray Burst Monitor (GBM) on NASA's Fermi Gamma-ray Space Telescope picked up a brief, weak burst of high-energy light consistent with the same part of the sky. Analysis of this burst suggests just a 0.2-percent chance of simply being random coincidence. Gamma-rays arising from a black hole merger would be a landmark finding because black holes are expected to merge "cleanly," without producing any sort of light.

"This is a tantalizing discovery with a low chance of being a false alarm, but before we can start rewriting the textbooks we'll need to see more bursts associated with gravitational waves from black hole mergers," said Valerie Connaughton, a GBM team member at the National Space, Science and Technology Center in Huntsville, Alabama, and lead author of a paper on the burst now under review by The Astrophysical Journal.

Detecting light from a gravitational wave source will enable a much deeper understanding of the event. Fermi's GBM sees the entire sky not blocked by Earth and is sensitive to X-rays and gamma rays with energies between 8,000 and 40 million electron volts (eV). For comparison, the energy of visible light ranges between about 2 and 3 eV.

Black hole mergers were not expected to emit significant X-ray or gamma-ray signals because orbiting gas is needed to generate light. Theorists expected any gas around binary black holes would have been swept up long before their final plunge. For this reason, some astronomers view the GBM burst as most likely a coincidence and unrelated to GW150914. Others have developed alternative scenarios where merging black holes could create observable gamma-ray emission. It will take further detections to clarify what really happens when black holes collide.
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http://www.nasa.gov/feature/goddard...poised-to-pin-down-gravitational-wave-sources


The following paper was linked to earlier in these confirmation of GW's and BH's discussions but I see it appropriate to post again in line with the current progression.
http://arxiv.org/pdf/1602.04735v2.pdf
Abstract:
Mergers of stellar-mass black holes (BHs), such as GW150914 observed by LIGO, are not expected to have electromagnetic counterparts. However, the Fermi GBM detector identified a γ-ray transient 0.4 s after the gravitational wave (GW) signal GW150914 with consistent sky localization. I show that the two signals might be related if the BH binary detected by LIGO originated from two clumps in a dumbbell configuration that formed when the core of a rapidly rotating massive star collapsed. In that case, the BH binary merger was followed by a γ-ray burst (GRB) from a jet that originated in the accretion flow around the remnant BH. A future detection of a GRB afterglow could be used to determine the redshift and precise localization of the source. A population of standard GW sirens with GRB redshifts would provide a new approach for precise measurements of cosmological distances as a function of redshift.

Discussion:
We described a novel mechanism for a prompt electromagnetic counterpart to the merger of stellar-mass BH binaries, such as GW150914. The proposal was motivated by the Fermi GBM detection of a γ-ray transient 0.4 s after GW150914 (Connaughton et al. 2016). Even if these two signals are unrelated, the possible existence of electromagnetic counterparts to BH mergers at cosmological distances argues in favor of sending LIGO alerts for follow-up observations by radio, infrared, optical, UV, X-ray and γ-ray telescopes. The inferred GRB luminosity for GW150914-GBM (at photon energies between 1 keV and 10 MeV) of 1.8+1.5 −1.0 × 1049 erg s−1 and its measured duration of 1 s (Connaughton et al. 2016) are significantly lower than their typical values in long-duration GRBs (Meszaros & Rees 2014). The observed GRB may be just one spike in a longer and weaker transient below the GBM detection threshold. The weakness of the burst could be attributed to the extended envelope of the very massive progenitor star, from which the GRB outflow just barely managed to escape (Bromberg et al. 2013). For this to work, the BH activity must have persisted for roughly the light crossing time of the star, ∼ 14(M⋆/100M⊙) 1/2 s. In particular, the low GRB luminosity could have resulted from a broader than usual opening angle of the GRB outflow as it slowed down and widened just before exiting the stellar envelope. A broad GRB outflow brings the added benefit of removing the need for a rare alignment between the line-of-sight and the central axis of the outflow. The parameter fit of LIGO disfavored orientations where the orbital angular momentum of the BH binary is misaligned with the line of sight (see Figure 2 in LIGO & Virgo 2016a). The main advantage of the single star origin for GW150914-GBM is that it naturally provides a high infall rate of gas around the merging BHs. The γ–ray luminosity of GW150914-GBM corresponds to a mass infall rate of ∼ 1/(ǫ/10−5 )M⊙ s −1 , where ǫ is the efficiency of converting accreted mass to the observed γ-rays. An accretion from a long-lived disk (e.g., originating from the tidal disruption of an ordinary star) around the BH binary would be typically limited to the Eddington luminosity (Kamble & Kaplan 2013), which for a binary mass of M ∼ 65M⊙ amounts to ∼ 1040 erg s−1 , a factor of ∼ 109 lower than the inferred γ-ray luminosity in GW150914-GBM. A future detection of a GRB afterglow would allow to determine the redshift and precise localization of the GW source (but see the upper limits in Smartt et al. 2016; Soares-Santos et al. 2016). Since LIGO detected GW150914 only shortly after starting to collect data at its improved sensitivity, it will likely detect many similar events during its future operation. A population of standard GW sirens with GRB redshifts would provide a new path for measuring cosmological distances as a function of redshift to a high precision (Hughes & Holz 2005; Nissanke et al. 2013). Numerical simulations are required to better characterize the detailed hydrodynamics and neutrino cooling associated with a binary BH formation through a dumbbell configuration during the collapse of the core of a massive star. Magnetic fields could also play an important role in transporting angular momentum and mediating the collapse of the two clumps.

 

The laws of thermodynamics say that energy cannot be created or destroyed, but then random particle pair creation and annihilation violates this law. Then that doesn't invalidate the experimental discovery of random particle pair creation and annihilation, which results into a photon that was not there before.

I should have been more clear when I stated that I didn't understand something. What I meant really was why these fields exist, and how we know that they should exist in this manner.

I think the density of a suppermassive black hole is far from meaningless. With the amount of gravitational force acting on anything inside of a black hole, it should make it collapse to the smallest size possible. Then the event horizon should be smaller. If the solar system was completely filled with water, it would have enough mass to make a black hole. Then you would expect the water to be crunched down into a singularity, not just create an event horizon the size of the solar system.

 

But, neutron stars and similar bodies do not have event horizons. How could we be sure if that is actually what it is if we have never actually seen a black hole or its accretion disk?

When I heard about the formation of jets before, it was generated by a star falling into a black hole. I don't think one star could account for most of these "jets" coming out of the center of a lot of galaxies. The jets I have seen didn't appear to have interruptions or spacing in their jets, indicating time periods of the black hole not feeding...

Exactly, no one has ever witnessed an accretion disk, because they only know they are there from the motion of other stars around them.

A white hole wouldn't have a jet, exactly. It would just spew out an infinite amount of energy from a singularity, opposite of what a black hole would do. Basically, a white hole is the other end of the "wormhole" of a black hole in which the singularity has moved to another point in spacetime through hyperspace. Then if the parent black hole was spinning, then it's corresponding white hole would have that spin, because it comes from black holes. The only reason why the energy would be infinite though is because GR breaks down at the point of a singularity, and everything that comes out of a white hole would have to pass through a singularity. So, it could be more accurate to say that it is just not calculable or it is undefined. If a white hole was able to lose energy and mass, then it could collapse into a supper-massive black hole, which could explain why supper-massive black holes do not collapse on themselves. It could remain under the pressure of a much larger black hole on the other side of the universe, which would mean that we are on the ass end of the universe. (just the last part there was a joke)

 

You could think of a white hole as like the bottom half of an hour glass, and the black hole is the top of the hour glass. The sand would be all the matter and energy that has got sucked in by a black hole. It would then travel through a tunnel like the middle part of the hour glass, which would be similar to a wormhole. A white hole would have an open singularity, as opposed to a black hole having a closed singularity. If enough mass accumulated around the open singularity, it could then form an event horizon. The event horizon is what makes a singularity a closed singularity (black hole).

To me, it seems like it would be just as reasonable or even more reasonable to assume that a suppermassive black hole is just like the bottom half of an hour glass that has already been filed up. It would seem like it would be more along the scale of galaxies, being a jet from a white hole. It would explain the mystery behind suppermassive black holes low density. It could possibly explain the amount of dark matter of galaxies, from this singularity existing in hyperspace. It could even possibly explain the increasing exponential expansion of the visible universe, if you assume that the opposite side of the universe is more massive (which could create white holes in the center of every galaxy). I think there is a big potential for this being able to explain mostly everything we don't understand in theoretical physics right now, just by assuming that every suppermassive black hole is a white hole that has died out or closed its singularity.

 

I'm not sure what you mean by this. The entire point of what I said is that all compact strong gravity sources form accretion disks under the proper conditions. We can actually see accretion disks around the black holes at the centers of galaxies, and around black holes in X-ray binaries. The orbits of the visible accretion disk and the companion star in an X-ray binary, given the mass of the visible companion star, tells whether the object at the center of the accretion disk is a neutron star or a black hole. And the orbits of stars and the accretion disk around the central black hole in a galaxy give the mass of the central black hole.

Let's have a reference for that. A star cannot survive near enough to a SMBH to fall in whole; they get "spaghettified" by the tidal forces and their material streams into the accretion disk. I have never seen even a pop-science source that claims that stars fall whole into black holes.

Errr,

http://hubblesite.org/newscenter/archive/releases/1994/23/text/

Emphasis mine.

Errr, see the previous link.

Note please that this is from 1994, twenty years ago. Twenty years ago there was still some question as to whether these objects were black holes or not; today it is generally accepted.

As for white holes I think that was adequately addressed when I noted that they require antigravity.

 

Of course it's meaningless....A BH's perimeter is the EH, then all we have is critically curved spacetime right up to the Singularity at the Planck/quantum level at the center.
Once the Schwarzchild radius is breached, yes further collapse is compulsory, at least up to the quantum/Planck level where GR does not apply.
A BH may lead to infinite density and curvature at the singularity, but the mass always remains finite.
NOTE: While I speak of density, it is the density of the mass residing at the singularity according to GR, not the density of the whole BH up to the EH, which is nothing more than critically curved spacetime.

 

A BH can never be said to be a glutton: Any massive object approaching the BB, and at least reaching 1.5 Schwarzchild radius [where light will orbit and from memory the inner most disk of any accretion disk] will shred that mass and it will form the accretion disk, that then spirals into the BH's EH in a continuing gradual process.

Again, from memory, I'm sure accretion disks have been observed...I think?
It's from the speed of these accretion disks, and the increasing speeds as the shredded matter falls into the BH, approaching "c" that are the large part of the evidence suggesting BH's.

 

We definitely don't know what happens inside a BH. The only definition of "density" we can sensibly apply without speculating is the total mass of the BH and the volume enclosed by the EH.

We don't know that. We know that our theories don't extend beyond the EH, and we know that gravity comes out of BHs and they have mass. The no hair theorem (q.v.) applies here. BHs have mass, spin, and electric charge, and that seems to be all we can see from out here.

Now that I agree with.

Actually, the overall density can only be seen from out here as the mass of the BH over the volume of the EH.

 

Yes, they have been observed, and it's not only the accretion disk speeds but also the orbits of nearby stars (in the case of X-ray binaries, and SMBHs at the cores of galaxies).

Remember that Hubble saw the accretion disk at the center of M87 in 1994 (which I linked above, you can read the text of the press release, and view the image for yourself) and this was the final confirming evidence for the existence of SMBHs at the centers of a lot of galaxies, but that's not all we see; we also see the orbits of stars outside the accretion disk.

Remember also that we see lots of examples of accretion disks not associated with black holes but with other compact gravity sources all the time. Given that something less extreme than a black hole can form an accretion disk, it's a slam-dunk that a black hole can.

 

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I had this out a few months ago with a particular good friend of mine, one that likes to mention my handle in just about every post.

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Let's take an example: If we were to observe an ergosphere for example, Isn't it logical and reasonable to assume with some confidence that the BH is a Kerr metric?
And isn't it logical to assume that BH's are all born spinning [again Kerr metric] since the stars from whence they are formed are also spinning.
And of course in both cases, we can reasonably ascertain a ring singularity.
In the prior discussion on this Schneibs, I e-mailed Professor Hamilton and a few more were e-mailed also by a member called tashja, and they seem to confirm my line of thinking...which is: We are allowed to reasonably assume some properties such as I spoke of, for inside the EH, based on what we observe outside.eg; the ergosphere.

 

I'm pretty sure that the equations of GR tell us that once the Schwarzchild radius is reached, further collapse is compulsory: This also was confirmed by Professor Hamilton and others, and also by a professional GR theorist I often crossed swords with on a now defunct forum.

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I'm always very cautious about making any statements about what's going on inside the event horizon. Until we have quantum gravity I don't think we know enough to say. When you cross the EH, the center of the black hole is your future. I don't mean it is in your future; I mean the direction of the flow of time for you is in the direction of the center of the BH. Wait what does that but you can't I don't even.

I'm not arguing with your other correspondents; I'm saying I don't think there's enough information to even make an argument.

 

No probs!
If I can find the past correspondents from the relevant Professionals, I'll post for your perusal.

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Totally in agreement with the no hair theorem by the way. A Penrose edict was it not?

 

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Actually Wheeler is usually quoted, but he says in an interview that he heard it first from Jacob Bekenstein.

 

John Wheeler, OK!
He also coined that other familiar edict summing up GR, "Spacetime tells matter how to move; matter tells spacetime how to curve"

 

Wheeler was probably one of the most capable gravity physicists of the 20th Century, and is virtually unknown to the general public. He was also fairly expert in quantum mechanics, which is unusual for relativists; for example, he collaborated with Feynman on Wheeler-Feynman absorber theory, which today forms the basis for Jack Cramer's Transactional Interpretation of Quantum Mechanics.

He is the co-author of the book most gravity physicists have learned the basics from; its title is simply, Gravitation. His co-authors are Kip Thorne and Charles Misner.