How can gravity escape a black hole?

[modest]

Originally Posted by Jay-qu

Thinking about gravitons can get you a bit mixed up because no one knows if the graviton exists or not. Our current theories just dont cut it. If we can quantise gravity and attribute a guage boson to the gravitational force, it would be known as the graviton and if that occurs we expect the graviton to be massless. But that doesnt ensure it can escape a black hole - as a photon is massless and cannot escape.

This is a good point and it has me thinking... black holes are theorized to have electric charge. We know virtual photons are the mediators of charge and they also would have to travel faster than c to communicate the charge of a black hole. In this manner, we can leave gravitons out of the conversation and still focus on the intriguing aspect (or at least, the aspect that I find intriguing.)

~modest

[Pluto]

G'day from the land of ozzzzzzzz

I like to share this link

[0805.1519] Constraints on the massive graviton dark matter from pulsar timing and precision astrometry

Constraints on the massive graviton dark matter from pulsar timing and precision astrometry

Authors: Maxim Pshirkov, Artem Tuntsov, Konstantin A. Postnov
(Submitted on 11 May 2008)

Abstract: We show that the existing millisecond pulsar timing measurements strongly constraint possible observational consequences of theory of massive gravity with spontaneous Lorentz braking [1], essentially ruling out significant contribution of massive gravitons to the local dark halo density. The bounds are especially strong considering the difference of massive graviton propagation velocity from the speed of light. Present-day astrometrical constraints are shown to be less stringent than those due to pulsar timing.

I'm still reading through links on gravity. Trying to understand the topic on gravity when nobody really knows.

I now know that I know less after reading many papers.

I think I will go and play tennis.

[Jay-qu]

True. I wonder what the consequences would be if this charge was immeasurable. ie If the black hole has a charge but it cannot be felt, is it a meaningless question to ask what this charge is..

You could test this with Hawking radiation, I would assume a charged blackhole would be more likely to swallow the oppositely charged particle/anti particle, then the radiation it emits will be mostly of the same charge of the black hole. Then this would lead to the idea that charge is radiated away from a black hole.. is this true or am I talking crap?

[Pluto]

G'day from the land of ozzzzzz

Jay-qu you maybe right.

But! right now I'm just reading through papers, I'm leaving my mind open and not concluding or assuming what is right or wrong.

I know that alot of this work is very theoretical.

[astro-ph/0701258] Long Gamma Ray Bursts from Quark Stars

Long Gamma Ray Bursts from Quark Stars

Authors: P. Haensel, J.L. Zdunik
(Submitted on 9 Jan 2007)

Abstract: If strange quark matter (SQM) is the true ground state of hadronic matter, then conversion of neutron stars (NS) into quark stars (QS) could release some 10^{53} erg. We describe a scenario of burning of a NS into a hot, differentially rotating QS. Emission of released non-baryonic energy through the QS surface is discussed. The role of magnetobuoyancy of SQM is mentioned. The outflow of gamma e+ e- lasting for up to ~1000 s could be at the origin of long GRBs. Advantages of hot, differentially rotating QS as an inner engine of long GRBs are reviewed.

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and this link is quite interesting

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[astro-ph/0701240] Transition to Quark Matter and long Gamma Ray Bursts

Transition to Quark Matter and long Gamma Ray Bursts

Authors: Alessandro Drago, Giuseppe Pagliara, Irene Parenti (Univ. Ferrara and INFN Sez. Ferrara, Italy)
(Submitted on 9 Jan 2007)

Abstract: The energy released by the inner engine of GRBs can originate from structural readjustments inside a compact star. In particular, the formation of deconfined quark matter can liberate enough energy to power the burst. We show that the burning of a neutron star into a quark star likely proceeds as a deflagration and not as a detonation. In that way no strong baryon contamination is produced near the surface of the star. It is tempting to associate the temporal structures observed in the light curves with specific processes taking place inside the compact star. The so-called quiescent times, during which no signal is emitted in the highest energy band, correspond to pauses during the processes of readjustment. If the quark (or hybrid) star formed after these transformations is strongly magnetized and rotates rapidly, a prolonged gamma emission can be produced, as proposed by Usov years ago. This can explain the quasi-plateau observed by Swift in several GRBs.

If a black hole is treated as a ultra compact plasma matter, the properties of plasma can be applied.
The phrase that nothing can escape a black hole is correct. But! the process within the black can create a Z-pinch of the EM fields allowing matter to be ejected from the core of the compacted matter.

In Z-pinch experiments it is shown that normal matter can be broken down to Neutrons and compacted during the Z-pinch to extreme densities and a jet ejects matter out at high speeds.

I need at least a few years to understand.

[Michaelangelica]

I'm confused
So how come black holes spurt out all this matter?
that should be impossible??

[modest]

Originally Posted by Pluto

In Z-pinch experiments it is shown that normal matter can be broken down to Neutrons and compacted during the Z-pinch to extreme densities and a jet ejects matter out at high speeds.

Originally Posted by Michaelangelica

I'm confused
So how come black holes spurt out all this matter?
that should be impossible??

The two papers that Pluto links above are not related (in a direct way) to black holes. In fact, the phrase "black hole" appears only once between the two.

The most prevalent theory of gamma ray bursts involves the collapse of a supermassive star into a black hole. This is not a confirmed theory and the subject of the mechanism for GRB formation is very much still open. The papers that Pluto links attempt to support theories involving GRBs that do not involve black holes.

I will say that in neither theory of GRB formation (neutron stars or black holes) nothing is escaping a black hole. Nothing is theorized to escape the horizon as far as GRBs are concerned.

~modest

[Pluto]

G'day from the land of ozzzz

Gamma ray bursts evolve mainly from jet formation

I will come back to it later.

Got visitors.

arXiv.org Search

Thats the next topic on the reading list.

[Michaelangelica]

Sep 1, 2006
Almost certain escape from a black hole

Recent theoretical results have overturned the long-held notion that information cannot escape from a black hole, explains Seth Lloyd

You need to read the whole article
Almost certain escape from a black hole - physicsworld.com



So what is this stuff coming out of the middle of the Black Hole?

[modest]

Originally Posted by Michaelangelica

You need to read the whole article
Almost certain escape from a black hole - physicsworld.com

So what is this stuff coming out of the middle of the Black Hole?

Ok, I think three different things are now getting mangled together into one confusing result.

The two articles Pluto presents in post 14 talk about gamma ray bursts. GRBs are neither related to this thread's topic nor the article you post above Michaelangelica. So, I'm going to ignore them in this post.

The article you post above, Michaelangelica, is not related to the picture that accompanies it. The picture is of a black hole jet (the accretion of matter from near a black hole), and the article is about hawking radiation.

Hawking radiation was theorized by Steven Hawking. It is the proposition that black holes slowly evaporate due to quantum mechanical effects. Before Hawking proposed this radiation, it was generally believed that the mass falling in a black hole would be forever trapped inside. It's now believed that mass slowly leaks out. There are two threads on Hypo talking about this:

Hawking Radiation
Hawking Radiation, again.

and the subject of the article you post (ie hawking changes his mind about black holes destroying information) is talked about in this thread:

Hawking redefines his black hole theory

But, the picture you post is not showing Hawking radiation. It is showing a supermassive black hole with an accretion disc and jet.

This article describes it well:

SPACE.com -- Powerful Black Hole Jet Explained

In the case of a black hole jet, nothing escapes from inside the event horizon (unlike hawking radiation). The jet does not lessen the mass of the black hole. The matter falling in toward the hole in the accretion disc gets accelerated to reletivistic speeds helped along by magnetic forces. The matter is ejected at enormous speeds at the two poles without ever crossing the event horizon.

~modest

[Karnuvap]

This question pre-supposes that a gravitating object "Radiates" gravity. If this were so then it would be useful to ask how that radiated 'stuff' is able to escape the black hole's event horizon.

However - this is not how Gravity works. According to General Relativity (GR) massive objects distort spacetime (the most common visualisation of this is the bowling ball on a rubber sheet) and so objects 'fall' towards heavy objects simply because it is the 'line of least resistance' to do so through spacetime that has been distorted by a mass.

Now, if that mass was 'bouncing up and down' (or in 3-D if it is orbiting another mass, as in a binary system) then the 'rubber sheet' would ripple like the surface of a pond. These ripples carry away energy from the object as either Gravity Waves or Gravitons (just different ways of looking at it). So, for example, a neutron star orbiting outside the event horizon of a black hole would radiate Gravity Waves that ought to be detectable.

However, once the neutron star has crossed the event horizon of the black hole it could merrily continue orbiting for a while yet before plunging into the singularity at the centre but now (due to the distortion of space and time axes within the black hole) the gravity waves would NOT escape - the mass of the black hole would increase and thus the diameter of the black hole would grow but it would stop radiating gravity waves.

Thus you could say that black holes do trap gravity.

Hope this helps

The Vap.