CERN and black hole

[modest]

Originally Posted by Moontanman

Could something that much smaller than an electron even eat an electron? Could it compress an electron? It certainly couldn't tear an electron apart, it has no parts.

Yeah, it all seems a bit speculative to me. General relativity being about the big and quantum mechanics being about the small - I don't see how they come up with any answers to this stuff. I know it's way out of my league.

The things that get trapped in a black hole are the things inside the Schwarzschild radius If it's not inside that then it's not trapped. Baryonic subatomic particles are too big to fit inside the schwarzschild radius (event horizon) - so could they ever really be inside the black hole? Maybe not.

If they do somehow get in there I don't see them sticking around long. Quantum particles aren't known for holding still. Quantum tunneling is well enough established. Anything that gets trapped (including the particle that made it) may evaporate instantly even without hawking radiation

Originally Posted by Moontanman

How many millions of years would it take such a small black hole to grow big enough by consuming particles small enough for it drag into it's event horizon.

Yeah, who could say? If they eat anything that touches them then I can't imagine it taking more than hours to eat the earth. If it's more like a neutrino and hardly wants to interact with anything then It would take a very long time. I don't see how anyone could know for sure.

Originally Posted by Moontanman

are there any particles small enough for it to drag into it's even horizon? Photons maybe? I'm betting it would take millions if not billions of years for it to grow big enough to consume any thing other than possibly photons.

Hey - we were on the same wavelength about the event horizon there A photon is a point particle in QM, so maybe. But, in string theory it is 10^-44 meters so maybe not

Originally Posted by freeztar

That seems immeasurably small. Would we even be able to detect that one was created? EDIT: I guess we could indirectly detect them via the presence of muons and such?

I have no idea, I'll look into it. I honestly need to do that before I start answering

I really don't take these threats too seriously considering the energies that cosmic rays bombard earth's atmosphere with regularly. In four and a half billion years that has never been a problem. High speed jets coming off black holes and stars would similarly be filled with tiny black holes which one would imagine would be all around the interstellar medium. If miniature black holes were possible by anything we're going to do at LHC then I'd think nature already would have filled the galaxy with them by now. That not being the case, I think we're safe.

~modest

[freeztar]

Originally Posted by modest

But, in string theory it is 10^44 meters so maybe not

Typo?

[modest]

Originally Posted by freeztar

Typo?

alright wise guy 10^-44

[tmm35]

Does anyone know the relative speeds and trajectory of possible MBH created by cosmic rays. If their argument for safety is that cosmic rays may create them and we are still here then should they not mimic the conditions of a cosmic ray collision in LHC rather. Since we are talking about so many unknowns that would seem to be the minimum standard for safety.

[CraigD]

Welcome to hypography, tmm35!

Originally Posted by tmm35

Does anyone know the relative speeds and trajectory of possible MBH created by cosmic rays. If their argument for safety is that cosmic rays may create them and we are still here then should they not mimic the conditions of a cosmic ray collision in LHC rather.

The LHC’s most energetic collisions – those involving lead nuclei – are a bit over eV (1150 TeV). It’s max for a proton (hydrogen nuclei) collision is a little over eV (14 TeV).

Cosmic rays, the highest energy kind which are mostly protons and helium nuclei – have been detected with energies over eV – that is, over 100,000 times as energetic as the LHC can create.

So the LHC can’t mimic the highest energy cosmic ray collisions, because it’s not powerful enough. Though it’s the most powerful accelerator made by humans, it’s still puny by the standards of the cosmos – though much more conveniently located to its detectors.

As for trajectories – ie angle of impact – any other than a head-on, 180°, simply results in a lower-energy collision, so are not a significant factor.

Though physicists usually don’t, you can convert from a particle energy to a velocity by algebraically manipulating the mass dilation formula

into


The mass of a proton is about eV (938 MeV), So the speed of a eV proton is about 0.999999995 c. The mass of a lead atom is about 200 times (208.76) that of a proton, so a eV lead nucleus has about the same speed as a eV proton. The speed of a eV proton is about 0.99999999999999999999995 c (if I haven’t miscounted a 9 – now you can see why physicists usually prefer to use the energies of high-speed particles, rather than their speeds.

[tmm35]

Thanks for calculations of input paticle velocity and trajectory but the main issue is output paticle (i.e. potential black hole) velocity and trajectory. I havent seen any calculations on this but my understanding of physics say that a LHC collision of particles of equal mass traveling in opposite directions would yeild output particles of nearly zero velocity realtive to earth and trajectory of input particles. A CR collision of simillar particles would yeild output particles of much higher velocity relative to original trajectory and earth. This would mean that potential dangerous objects output from LHC collision would remain here on earth whereas those from a CR collision would fly away into vacum of space where there is no other objects to interact with and those would have no affect to earth. CR having higher energies only makes the CR velocities higher and less risk to earth since.

So if LHC is claiming we are safe since CR collisions havent created output particles that have damaged the earth then they need to make sure the output particles of LHC collisions mimic simillar output velocities as CR collision. Has LHC published or has anybody taken the time to calculate the velocity of output particles ?

p.s. I do understand that meeting the criteria of ensuring output particles are ejected into space rather then remain on earth means limiting energy level LHC collisions. If that is minimal thing to do though to ensure safety of countires in locality of LHC and possibly the entire planet LHC and all there representatives should be taking that responsability for ensuring safety.