Large Hadron Collider (LHC) in action

[path_of_one]

That's why I wondered, Q. From my (very) limited knowledge, time slows down as one nears the event horizon, and being within it means one can't necessarily tell one is in there. Some clever person (forget who) pointed out our whole universe could be existing in the event horizon of a super-huge black hole and we'd never know it until we're sucked in completely. That was a fun thought.

I suppose I wondered if they *had* created a black hole, if that would be immediately apparent, or if it might start off very, very tiny... and go unnoticed until its mass and force pulled us in. What would happen to time? To space? When would we notice and why?

I still like to imagine, despite the improbability, that black holes are actually wormholes. Fun!

[Tao_Equus]

Originally Posted by path_of_one

I suppose I wondered if they *had* created a black hole, if that would be immediately apparent, or if it might start off very, very tiny... and go unnoticed until its mass and force pulled us in. What would happen to time? To space? When would we notice and why?

If they had created a black hole it would instantly decay. The smaller a black hole is the faster it decays.

Even if you managed to make this 25 femtogram black hole, it would decay into normal matter incredibly fast. How fast? According to Hawking radiation, this black hole will be gone in 10-66 seconds, which means, unless there is some incredible new physics (like extra dimensions), we can’t even make a black hole! Why not? Because anything that happens in a time less than the Planck time (10-43 seconds) cannot physically happen with our current understanding of physics.

LHC Black Holes: Worst Case Scenario | Starts With A Bang!

On the other hand if a black hole is very small the radiation effects are expected to become very strong. Even a black hole that is heavy compared to a human would evaporate in an instant. A black hole the weight of a car (~ 10-24 m) would only take a nanosecond to evaporate, during which time it would briefly have a luminosity more than 200 times that of the sun. Lighter black holes are expected to evaporate even faster, for example a black hole of mass 1 TeV/c2 would take less than 10-88 seconds to evaporate completely.

Black hole - Wikipedia, the free encyclopedia

I tried to search for some articles I read recently that suggest even stellar black holes, (black holes formed by the supernova of a single massive star), do decay quite rapidly but too much to trawl through at the moment. But the suggestion is there!

What I find interesting about this whole issue though is that from what we do know the creation of a black hole is so remote that it should never even have been suggested. Who did suggest it....and why? That I would like to know.


tao

[earl]

Talk about black holes. For a guy that's any attempt to find something in their wife's purse. earl

[Quahom1]

Originally Posted by earl

Talk about black holes. For a guy that's any attempt to find something in their wife's purse. earl

As long as it isn't her heart...

[Dream]

What do you get when you accelerate two blonds towards each other, each traveling 99.9% of the speed of light relative to a stationary tube of lipstick?











a red dwarf

[Quahom1]

Originally Posted by Dream

What do you get when you accelerate two blonds towards each other, each traveling 99.9% of the speed of light relative to a stationary tube of lipstick?











a red dwarf

A pink...oh, i'm not goin' there.

[juantoo3]

Originally Posted by Tao_Equus

If they had created a black hole it would instantly decay. The smaller a black hole is the faster it decays.

I wondered about that.

I'm certainly not versed well enough to speak with any authority, but I wondered if a black hole would require a "critical mass" in order to continue its perpetuation...

[Quahom1]

Originally Posted by juantoo3

I wondered about that.

I'm certainly not versed well enough to speak with any authority, but I wondered if a black hole would require a "critical mass" in order to continue its perpetuation...

Woah, that is a theory. We haven't actually created a singularity yet. Furthermore, we have NEVER actually seen a singularity directly. And we do not know for absolute certainty, what is required for critical mass (since we are delving/plunging into quantom physics/special relativity, which we are at about kindegarten level of knowledge, and which Einstein never worked the bugs out of).

We are going where no one has actually gone before...

Even S. Hawkins was hesitant on this one...

[juantoo3]

NOVA | Einstein's Big Idea | PBS

Einstein's Big Idea

An excellent PBS/NOVA program, I highly recommend, covers a whole lot of turf from the influential science leading up to Einstein's theory, and the lady who picked up where Einstein left off who figured out how to unleash the atom. Her nephew was a contributor to the Manhatten project.

[path_of_one]

Really interesting stuff, Tao. Do they know at what point a black hole seems to be "stable" enough (wrong word, I know, but I can't think of the right one) to keep going? What has to happen for the black holes out there to have occurred and kept going?

[bob x]

Originally Posted by juantoo3

I wondered about that.

I'm certainly not versed well enough to speak with any authority, but I wondered if a black hole would require a "critical mass" in order to continue its perpetuation...

It's not a sharp line. Under Hawking's interpretation, the more mass it has, the slower it radiates. To form a black hole without a high-speed collision, simply from gravitational pressure forcing all the particles together, requires about 2.3 times the mass of the sun; this size black hole will hardly radiate at all, something like one photon per trillion years. But that is 50 orders of magnitude larger than the black holes the LHC could theoretically produce, which Hawkings says would radiate away in a trifling fraction of a second.

[Tao_Equus]

Originally Posted by path_of_one

Really interesting stuff, Tao. Do they know at what point a black hole seems to be "stable" enough (wrong word, I know, but I can't think of the right one) to keep going? What has to happen for the black holes out there to have occurred and kept going?

I am not sure because science is not sure. Like I said I have read reports that stellar size black holes may be radiating far more than Hawkins Radiation predicts. According to Hawkins Radiation theory a stellar mass object should be emitting very little, so little that it would be stable for many billions of years without losing much mass at all. The smallest sized object I have seen associated as reasonably stable is about the mass of a car but it does not seem very likely to me. I dont think we really understand what black holes are yet on the bigger scales but I am pretty confident that molecular size black holes cannot exist. There seems to be enough consensus among the physicists on that to be fairly confident. Till of course we make one and it gobbles the Earth.


I still tend to think galactic black holes are a whole different kettle of fish. I think the mass of these objects is far greater than we are led to believe and that they account for much of the so called missing dark matter. The dark matter that is supposedly distributed amongst the stars and galaxies is deduced looking at the movement of the galaxies and galactic clusters in relation to each other. Another explanation for their momentum would be galactic black holes that are several orders of magnitude heavier than accepted. And theses objects sit in virtually every galaxy studied. But I digress...



tao