Questions 101

dragon04 · Jan 12, 2005

1. Evaporating Black holes. If they DO "evaporate", do they return to visible space as an object? If not, why not? 2. If they do, what do they return as? 3. What is the singularity made of? Neutrons or even more fundamental particles? 4. Could pulsars be black holes that lost sufficient mass to return to visible space? 5. I see and read a lot about "missing mass" relative to gravitational theories of the universe. We look and look to find that stuff. Is it possible considering that the red shift of the most distant galaxies approaches light speed that there is much more mass beyond them moving faster than light relative to us that we just can't see? I understand that the answers to these questions would be speculative, but I think about these things. <div class="Discussion_UserSignature"> "2012.. Year of the Dragon!! Get on the Dragon Wagon!". </div>

nacnud · Jan 12, 2005

1. Evaporating Black holes. If they DO "evaporate", do they return to visible space as an object? If not, why not? . They evaporate energy, normally in the form of x-rays. 2. If they do, what do they return as? . I think that they just evaporate x-rays until the mass has completely gone, a neutron star doesn't suddenly reappear after to much mass has been lost. 3. What is the singularity made of? Neutrons or even more fundamental particles? . What is a singularity? Good question. 4. Could pulsars be black holes that lost sufficient mass to return to visible space? . No, pulsars are rapidly spinning neutron stars. As a star collapses into a neutron star it can radiate of energy but most of the angular momentum is kept. So take all the angular momentum in the sun but compress it into a ball 10s of kms across and it will spin very rapidly, just like a figure skater pulling their arms in. 5. I see and read a lot about "missing mass" relative to gravitational theories of the universe. We look and look to find that stuff. Is it possible considering that the red shift of the most distant galaxies approaches light speed that there is much more mass beyond them moving faster than light relative to us that we just can't see? I understand that the answers to these questions would be speculative, but I think about these things. The missing mass is because of the orbital velocity of stars in the outer regions of galaxies it too high if just the visible portions are there, hence the term dark matter. This happens even in close galaxies at low red shift. Take a look here [www.wikipedia.com] for more.

Saiph · Jan 12, 2005

1: They do not return as a single, cohesive, visible object. They completely disipate their contents as light and random atomic particles. This is much akin to how boiling water evaporates, and leaves nothing solid behind. The black hole leaves nothing substantial behind, having radiated it all as light and atomic particles. 2: They don't soo....there's the answer to that 3: We don't know. It's definetly a state of matter we are unfamiliar with, as nothing known today can withstand those conditions. 4: Nope, pulsars are nuetrons stars, things that failed to form BH's. Chuck in more mass, and you'll get a supernovae (and maybe a BH, but IIRC the explosion would just rip it to shreds, leaving nothing behind). 5: Yes, it is possible, and likely, that there is mass moving to fast for us to notice (actually, its stationary, but space is expanding and carrying it away from us). This, however, isn't what people mean by the missing mass problem (though it may be an answer to the dark energy problem). The missing mass is dark matter, and it is responsible for (or rather a possible explaination for) the continued survival of galaxies that are rotating to fast (and in an unexpected fashion) when one considers the amount of mass we can see there. I.e. from what we know is there, they rotate to fast. Therefore there must be stuff there we don't know about (or some forces we don't expect). <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

nacnud · Jan 12, 2005

Hum... it seems that a small black hole could be an efficient mass to energy converter, I feel a trip to the Sci-Fi section coming on.

igorsboss · Jan 12, 2005

Romulans.

nacnud · Jan 13, 2005

Dang beaten to it <img src="/images/icons/frown.gif" />

Saiph · Jan 13, 2005

Efficiency...I don't know about. I do know that the process is incredibly slow for any decent sized BH. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

nacnud · Jan 13, 2005

I think it would would for very small BHs on the scale of atoms or so but thats a SWAG

Saiph · Jan 13, 2005

right, cause if you lose magnetic containment.... The other problem with BH energy production: You've gotta lug that thing around! Even an atomic sized one weights more than a mountain. I don't think it can put out enough energy to sufficiently power an engine capable of moving it. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

Saiph · Jan 14, 2005

ummm... A million ton BH would evaporate in something like microseconds. How are you going to feed in enough mass, fast enough to sustain it? <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

newtonian · Jan 15, 2005

Dragon - OK, where are the other 96 questions? 1. I am not aware of any observational evidence black holes evaporate. Are you talking about Hawking radiation? 2. Black holes remain. 3. Theories vary. Perhaps strings as in string theory. That may be smaller than quarks in size. Perhaps even smaller than Planck length. 4. No, pulsars are supernova remnants, if I remember correctly. Very dense cores, they are actually one type of neutron star, that remain after the star ejects most of its mass. 5. The missing mass that causes galaxies to have the revolution speed properties that they have would be in halos around said galaxies. AKA Dark matter, which may be mostly ordinary matter that is simply dark- and it may also contain exotic or unknown matter. Missing mass beyond our visibility horizon may have an effect on the acceleration of expansion of our universe - one pet theory of mine - in a sort of domino effect.

newtonian · Jan 16, 2005

eburacum145 - Agreed. However, predicted effects caused by the predicted properties of black holes have been observed, [compare the predicted effects of an Intelligent Creator vs. blind chance] and therefore cause and effect does strongly support the existence of black holes. However, I am not aware of any effects predicted by Hawking radiation having been observed. For example, over a long period of time there should be a minute decrease in gravity from a black hole if its mass has decreased by this "evaporation." Yes, I know some feel the mass has left, and use variations of relativity theory to posit this, but I doubt it also. Are you aware of any observational evidence of effects predicted by the Hawking radiation hypothesis?

nexium · Jan 19, 2005

Because of the extreme density of millon ton black holes inside their event horizon, they don't lose much speed when they pass though solid objects. The diameter of the event horizon of a million ton black hole is about the same as an atom. It could have a microscopic accreation disk, which is very destructive over microscopic distances. The accreation disc converts matter to energy with high efficiency. The hawking radiation would be destructive at a distance of one millimeter and is perhaps detectable to a distance of one kilometer. The radiation from the accreation disk may be detectable to several kilometers. Total mass loss will occur in about 2000 years, unless it can pull 500 tons of matter though its event horizon per year. Matter does not pass into the event horizon easily because of the intense hawkings radiation just outside the sub-microscopic event horizon. A few tons of matter entering per year would stretch out total mass loss to perhaps 2005 years. Black holes with less than a million tons of mass evaporate much more rapidly and fiercely, so they are very rare, unless new ones are being formed at a very high rate. Ball lightening may be caused by black holes with a mass of several million tons. Please comment, refute and/or embellish. Neil

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Questions 101

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