Matter out of black holes?

[johnandrew]

Hi there,

 

Energy from matter is there to be observed when radioactive material decays but I think I'm right in stating, that it wasn't until 1997 that anyone managed to achieve the reverse process, in a cyclotron.

There's lots of exciting observational data appearing about black holes right now. Reading the theory about bh's, it seems you have all of the necessary conditions for the creation of matter from energy. While there's much talk about the production of energy from the shredding of stars and such, nobody is talking about the creation of matter from energy. Can someone kindly tell me what I'm missing about black holes?

 

Cheers☺

[Sensei]

Energy from matter is there to be observed when radioactive material decays but I think I'm right in stating, that it wasn't until 1997 that anyone managed to achieve the reverse process, in a cyclotron.

 

No, you're not right.

Pair production is well known since at least 1948.

https://en.wikipedia.org/wiki/Pair_production

 

Energy from decay, is simply kinetic energy of outgoing newly produced particles.

If you have Beryllium-8, it decays quickly to two alphas for instance.

[latex]_4^8Be \rightarrow _2^4He + _2^4He + 91.84 keV[/latex]

Decay energy is split in half to each newly created alpha (Helium nucleus), as they have equal mass, so they will carry the same momentum, and same kinetic energy. Just in opposite directions.

Edited March 7, 2016 by Sensei

[Strange]

Energy from matter is there to be observed when radioactive material decays but I think I'm right in stating, that it wasn't until 1997 that anyone managed to achieve the reverse process, in a cyclotron.

 

Can you say what exactly you are referring to here? Cyclotrons have been used since long before 1997.

 

Reading the theory about bh's, it seems you have all of the necessary conditions for the creation of matter from energy.

 

What conditions are you thinking of?

 

While there's much talk about the production of energy from the shredding of stars and such

 

Can you explain what this means?

[johnandrew]

Thanks for the well informed response.

 

I was under the (apparently) erroneous impression that radioactive decay resulted in the production of electromagnetic radiation and that the high energy accelerated particles in a cyclotron could interact to produce mass.

 

My understanding, is that black holes with their enormous gravitation, pull in nearby bodies and their destruction results in the emission of high energy electromagnetic radiation.

 

Thanks in advance for your patience.

 

John

[swansont]

Thanks for the well informed response.

 

I was under the (apparently) erroneous impression that radioactive decay resulted in the production of electromagnetic radiation and that the high energy accelerated particles in a cyclotron could interact to produce mass.

 

 

Not erroneous, but conversion of energy into mass had been observed well before 1997. As Sensei has already noted, you can produce an electron and a positron from a photon of sufficient energy (more than 1.022 MeV). Particle accelerators converting kinetic energy into mass also predates 1997.

[Mordred]

It does in one sense. A bh can only handle so much incoming matter. The accretion disk can only handle so much. Some of the mass/energy gets radiated away via the accretion jets.

[Strange]

I was under the (apparently) erroneous impression that radioactive decay resulted in the production of electromagnetic radiation and that the high energy accelerated particles in a cyclotron could interact to produce mass.

 

Radioactive decay can produce electromagnetic radiation. And you are correct that this is results in a (tiny) loss of mass. But really it is the conversion of energy in one form (binding energy in the nucleus) to another form (gamma ray photons).

 

Both nuclear fission and nuclear fusion use the fact that the products of either splitting large atoms or fusing small ones results in a lower total mass and thus the release of energy.

 

And, yes, the kinetic energy of particles in particle colliders can create various massive particles (perhaps most famously, the Higgs boson in the LHC).

 

But any process that adds energy will (very slightly) increase mass. So the water in your kettle gets heavier when you boil it (but that is massively offset by the loss of water as steam!)

 

 

My understanding, is that black holes with their enormous gravitation, pull in nearby bodies and their destruction results in the emission of high energy electromagnetic radiation.

Actually, black holes don't pull in nearby bodies any more than any other object with the same mass. So, if the Sun suddenly turned into a black hole, the planets would carry on orbiting as if nothing had changed. (Although it would get very dark and cold.)

 

Although, when matter does fall into a black hole there are complex process of heating and interactions of the resulting plasma that result in the release of large amounts of energy: either just blowing away the infalling material or, in the extreme, generating polar jets. I assume that is the sort of process you are referring to?

[Mordred]

http://arxiv.org/abs/1104.5499 :''Black hole Accretion Disk'' -Handy article on accretion disk measurements provides a technical compilation of measurements involving the disk itself.

 

 

The article covers in extreme detail

The accretion disk

[johnandrew]

Terrific. I've got some reading to do, I see.

 

Many thanks for your kind responses.

 

John