PDA

View Full Version : Magnetic field extracts energy from black hole



Karl
2001-Oct-23, 12:56 PM
http://www.gsfc.nasa.gov/gsfc/spacesci/pictures/blackhole/nonspinning.gif

"Never before have we seen energy extracted from a black hole," said co-author Christopher Reynolds of the University of Maryland, College Park. "We always see energy going in, not out."

"The gravity in this region appears to be so intense that the very fabric of space twists around the black hole, dragging magnetic field lines along with it," said Wilms. "The magnetic fields tighten about the black hole, slowing its spin. This 'friction' heats the region to even higher temperatures."

I happened to be at ESTEC just after the XMM launch and got to attend a very nice party /phpBB/images/smiles/icon_smile.gif

http://www.gsfc.nasa.gov/topstory/20011015blackhole.html

Donnie B.
2001-Oct-23, 01:25 PM
On 2001-10-23 08:56, Karl wrote:
I happened to be at ESTEC just after the XMM launch and got to attend a very nice party /phpBB/images/smiles/icon_smile.gif


Hey... it's not *nice* to make your fellow BABBers green with envy... /phpBB/images/smiles/icon_rolleyes.gif

Chip
2001-Oct-23, 04:38 PM
On 2001-10-23 08:56, Karl wrote:
http://www.gsfc.nasa.gov/gsfc/spacesci/pictures/blackhole/nonspinning.gif

"Never before have we seen energy extracted from a black hole," said co-author Christopher Reynolds of the University of Maryland, College Park. "We always see energy going in, not out."

"The gravity in this region appears to be so intense that the very fabric of space twists around the black hole, dragging magnetic field lines along with it," said Wilms. "The magnetic fields tighten about the black hole, slowing its spin. This 'friction' heats the region to even higher temperatures."


Does this reinforce the notion that black holes may actually be bright? Material falling near the black hole is accelerated and super heated, flinging out radiation along the distorted magnetic fields? By "bright" I don't mean just in the visual range, but in addition to X rays, would it be possible that a black hole might appear to a hypothetical close up observer (not too close!) to be star-like? Just wondering.

Chip

MHS
2001-Oct-28, 12:04 PM
I read that too; very interesting stuff. But what do we have to think of this 'discovery'? Did we solve a piece of the puzzle or is it just getting more and more complicated?

> Michiel <

jkmccrann
2007-May-30, 02:35 AM
http://www.gsfc.nasa.gov/gsfc/spacesci/pictures/blackhole/nonspinning.gif

"Never before have we seen energy extracted from a black hole," said co-author Christopher Reynolds of the University of Maryland, College Park. "We always see energy going in, not out."

"The gravity in this region appears to be so intense that the very fabric of space twists around the black hole, dragging magnetic field lines along with it," said Wilms. "The magnetic fields tighten about the black hole, slowing its spin. This 'friction' heats the region to even higher temperatures."

I happened to be at ESTEC just after the XMM launch and got to attend a very nice party /phpBB/images/smiles/icon_smile.gif

http://www.gsfc.nasa.gov/topstory/20011015blackhole.html


Black holes are truly amazing natural phenomena when you think about it. The amount of power and energy that is created and centred on a black hole is really impossible to appreciate.

These animations though are well worth a look at and do prompt my imagination to run wild and try and attempt to appreciate their power. IMO Black Holes are probably the single most amazing thing out there and they are definitely one Exo-Solar Phenomena that I am keen to find out more about.

Tensor
2007-Jun-06, 01:57 AM
IMO Black Holes are probably the single most amazing thing out there and they are definitely one Exo-Solar Phenomena that I am keen to find out more about.

If you have not worked on learning the math, the best source would be "Black Holes and Time Warps: Einstein's Outrageous Legacy". I can't recommend it highly enough for those who don't have the math to understand the actual GR equations.

Northwind
2007-Jun-06, 03:13 AM
From link
Scientists for the first time have seen energy being extracted from a black hole. Like an electric dynamo, this black hole spins and pumps energy out through cable-like magnetic field lines into the chaotic gas whipping around it, making the gas -- already infernally hot from the sheer force of crushing gravity -- even hotter.

Like an electric dynamo!!

:lol:

The Gas??? It's a plasma, dominated by EM forces not puny gravity :mad:

pumps energy out through cable-like magnetic field lines?? :mad: They are Birkeland currents

And


The total energy output, or luminosity indicated by the spectrum, however, was too bright to be powered by gravity and the free fall of matter alone. Some additional power source must exist to boost the luminosity to the observed intensity.

Whats that power source I wonder? :rolleyes: I can see magnetic fields are going to be written as the main power source, and of course we all know that you MUST have and electric field to have a magnetic field :doh:

Is that a death knell for the "mainstream" explanation I can hear :shifty:

"mainstream" appears to be coming closer and closer to "accepting" that because 99.99&#37; of the universe is in a plasma state, and that EM forces dominate the big picture, until the plasma becomes neutral, then gravity takes over the running of the show :whistle:

Great link though, just goes to highlight just how messed up the "mainstream" have become!

Northwind
2007-Jun-06, 03:19 AM
Seems the process is quite common from absolute humongous big black holes all the way down to little petite brown dwarfs

As per my now locked thread in ATM HERE (http://www.bautforum.com/showthread.php?t=59260)

Explain that with just gravity ?

Tensor
2007-Jun-06, 04:21 AM
Is that a death knell for the "mainstream" explanation I can hear :shifty:

"mainstream" appears to be coming closer and closer to "accepting" that because 99.99% of the universe is in a plasma state, and that EM forces dominate the big picture, until the plasma becomes neutral, then gravity takes over the running of the show :whistle:

Great link though, just goes to highlight just how messed up the "mainstream" have become!

It's really funny how a EU/PU will jump up and down with glee when they find a report such as this and don't realize that this has been around the mainstream for over 30 years. I suggest you go back and read the entire article, not just the parts you want to see. The Blandford-Znajek process was proposed over 30 years ago. This is observational support for that process, and it's been fully a part of the mainstream for that long.

I have yet to see even an OOM calculation from any supporter of EU/PU. Care to provide one that matches this observation? I don't want "It looks like...." I want the full equation that come close to the calculations from the Blandford-Znajek process, (here (http://www.citebase.org/fulltext?format=application%2Fpdf&identifier=oai%3AarXiv.org%3Aastro-ph%2F9902352) is an example that builds on the the process by extending its original simplifying assumptions). Otherwise, you're just blowing smoke.
When are the EU/PU people gonna take off the blinders and admit that gravity plays a major role? Failing that, could we, at least, get some good equations, instead of ".... That looks just like.....".

publius
2007-Jun-06, 05:17 AM
And I'll add this process is Maxwell "piggybacking" on General Relativity. It is the frame dragging/gravitomagnetic effects (heck, the entire gravitational field as described by General Relativity) that is choregraphing that whole show. Oh, and Northwind, the gravitational field near a Kerr Black Hole is far from "puny". Far from puny indeed. It is these strange strong-field effects predicted by General Relativity that is guiding this process.

And try to add something halfway constructive to this, many may be wondering just how you get something (energy) out of a black hole, if it is like a big roach motel where things go in but they don't go out. :) Well, the reason you can't "cancel out" a Schwarzchild black hole is because you can't throw negative mass in. If you could, you would cancel it out (and this is exactly what the Hawking radiation process is doing).

However, with a rotating black hole, that has a given angular momentum, you can easily throw stuff with opposite angular momentum, and cancel the total out (from the external space-time). Roughly, that's how this stuff works. The energy picture is very complex, but that is roughly how this works. You can cancel out its mass, but you can cancel out its L.

The so-called "Penrose process" is one way to do it. This is another way, using EM processes.

-Richard

Peter Wilson
2007-Jun-06, 05:50 PM
Matter (m) falling into BH begins with potential energy equal to mc^2. Roughly 10% of this inherent energy is radiated away in the process of falling in. It's really no surprise that more of this latent energy can somehow manifest.

Contrary to the EUers, however, EM is the form in which this latent energy escapes; not the original source of it. The ultimate "source" of this energy is just its rest-mass...per GR :)

Hornblower
2007-Jun-07, 01:37 PM
Like an electric dynamo!!


So we have a big flywheel spinning a dynamo and making some additional fireworks in the process. Nothing ATM about that.

Rough analogy: Water going over the spillway of a dam and falling on a light bulb does not make the bulb glow. Let the water spin a dynamo's turbine and connect the resulting electric current to the filament and presto - a glowing filament. Very mainstream, if you ask me.

publiusr
2007-Jun-15, 08:16 PM
If only we had one 'nearby' to use as a super powerful generator...

m1omg
2007-Jun-15, 08:58 PM
Does this reinforce the notion that black holes may actually be bright? Material falling near the black hole is accelerated and super heated, flinging out radiation along the distorted magnetic fields? By "bright" I don't mean just in the visual range, but in addition to X rays, would it be possible that a black hole might appear to a hypothetical close up observer (not too close!) to be star-like? Just wondering.

Chip

It would actually blind you because of it's brighteness and will die from hard radiation if you observe acretting and/or not, extracting BH from close range. Even when there is no mag. field extraction, the inner part of the accretion disk is more that 100 000 000 degress Celsius hot, so the energy of the mag. extracting BH must be....incredible.

m1omg
2007-Jun-15, 09:01 PM
And guess what is the brightest persistent source of hard X-rays in the sky...