5 ms·
This reminded me of a question I've had knocking around in my head since I've heard of hawking radiation- the prediction is that the black holes slowly evaporat
by mrkstu 8y ago
This reminded me of a question I've had knocking around in my head since I've heard of hawking radiation- the prediction is that the black holes slowly evaporate into subatomic particles.
However, it seems to me at some point a critical juncture would be passed and the black hole would cease being bound gravitationally and the matter would be released similarly to a supernova or just spontaneously form a neutron star.
What is the fallacy in that thinking?
- goodcanadian 8y agoTheoretically, a black hole can exist at any mass as long as it is dense enough. It is true that a black hole won't form without enough mass to cause it to collapse, but once formed, it can evaporate down to nothing without ever becoming gravitationally unbound.
- ansible 8y agoIt has been theorized that tiny black holes may have formed shortly after the Big Bang, and have since evaporated.
- mrkstu 8y agoTheoretically it could evaporate but is there any necessity of that? Is exploding a theoretical possibility or once a stellar mass black hole forms is it thereafter in such a small circumference that it is stuck in that form until it evaporates?
- zaarn 8y agoWell, evaporation is simply a conclusion from hawking radiation. The black hole losses energy over this radiation, energy it produces from it's own mass. Since hawking radiation output increases relative to the size of the black hole as it gets smaller, eventually you end up with an explosion. I do believe that Kurzgesagt made a video that details what would happen with a blackhole with the mass of a coin in your pocket (short version: you die)
- adrianN 8y agoThe intensity of Hawking radiation is inversely proportional to the size of the black hole. It shrinks as it radiates and its output increases. Once the black hole is tiny, the level of radiation is intense enough that you could call it an explosion. This is why small black holes are excellent generators. You just dump some mass into them and they convert it rather quickly to radiation.
- mpfundstein 8y agoI think we found a solution to our garbage problem abd at the same time solve the energy question as well. Now we just need a tiny black hole!
- adrianN 8y agoIt's not as hard as you think. Check out this paper here for some pointers https://arxiv.org/abs/0908.1803 https://arxiv.org/abs/0908.1803
- OscarCunningham 8y agoThe temperature of a black hole decrease as it gets larger. A black hole colder than 2.7K will absorb energy from background radiation faster than it emits Hawking radiation. So it will get larger and cooler. Any black hole warmer than 2.7K will emit energy faster than it absorbs. This means it will get smaller and hotter, leading it to lose energy at an increasing rate until it has lost all its energy and evaporates. The cutoff is at around 4.5×10^22 kg (about the mass of the moon). The event horizon at this mass is only 0.13 mm.
- pc86 8y agoI've always wondered, what would happen if we were able to create a black hole of this small a scale and it didn't evaporate? Something with an EH of a fraction of a millimeter.
- OscarCunningham 8y agoIf we created it on earth? It would swallow the earth and destroy us. But to create one we would have to gather a mass greater than the moon onto the earth, so the gravitational effects would probably destroy us before the black hole formed. Black holes aren't as scary as people think. If being next to a black hole of mass M is bad, then being next to a rock of mass M is probably just as bad.