Lead collisions: Mini big bang a recurring phenomenon?

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KarelGabriel
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Lead collisions: Mini big bang a recurring phenomenon?

Post by KarelGabriel » Sat Nov 13, 2010 12:37 pm

Hi everyone,
Like I said in my introductory post, I like to be fully armed with arguments in favour of the LHC.
I usually fall back against critics with the argument that what happens in the LHC, naturally occurs all the time in the universe even so with higher levels of energy.
In 2008 and also now, I've read the CERN safety study and I can't find a direct answer to the following question:
"If the collisions that happen in the LHC, happen naturally all the time, then do mini big-bangs also occur all the time?"
This question is derived from an article of the Belgian state television, translated version can be found here. It's about reaching a record temperature by a mini-big bang in the LHC on Monday. The following is stated in the article:
"Such high temperature was not reached since one billionth of one second after the birth of the universe." (translation to English is correct)
So if this is such a rare event in the universe, my usual argumentation becomes invalid...
I'm hoping the journalist made a mistake in interpretation, because I can't find the same statement on any English speaking site. Even the CERN press site makes no mention of this record temperature.
Does anyone have more info on this?

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tswsl1989
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Re: Lead collisions: Mini big bang a recurring phenomenon?

Post by tswsl1989 » Sat Nov 13, 2010 1:58 pm

Temperature isn't all that important in the grand scheme of things. It's important when you're dealing with bulk matter - material properties are quite dependent on temperature! - but holds little relevance when you're dealing with individual particles in such small quantities. Remember that even at the interaction points where collisions take place, the beam pipe is mostly a vacuum. For individual particles, energy is the important quantity, and the energy of the collisions in the LHC is lower than several natural processes, as you already pointed out.

Kasuha
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Re: Lead collisions: Mini big bang a recurring phenomenon?

Post by Kasuha » Sat Nov 13, 2010 3:17 pm

KarelGabriel wrote:"If the collisions that happen in the LHC, happen naturally all the time, then do mini big-bangs also occur all the time?"
First of all, it's mostly PR. I'd not even call it "mini big bangs" because there is great difference between now and then - now it's a tiny droplet of quark-gluon plasma surrounded by (comparably to its size) vast amount of vacuum, while during big bang there was no vacuum around, all the universe was full of such matter and it was the energy contained in it that probably made the universe expand.
So well... the bulk of the universe by then had some temperature, and there is nothing in the today's universe capable of creating such high temperature in bulk matter ... including the LHC.

Particle collisions even more energetic than what happens in LHC are fairly common in the universe.

KarelGabriel
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Re: Lead collisions: Mini big bang a recurring phenomenon?

Post by KarelGabriel » Sat Nov 13, 2010 7:50 pm

Thank you both for your replies!
Temperature isn't all that important in the grand scheme of things. It's important when you're dealing with bulk matter - material properties are quite dependent on temperature! - but holds little relevance when you're dealing with individual particles in such small quantities. Remember that even at the interaction points where collisions take place, the beam pipe is mostly a vacuum. For individual particles, energy is the important quantity, and the energy of the collisions in the LHC is lower than several natural processes, as you already pointed out.
So what I'll remember as argumentation/proof, is that temperature has little relevance to particle interactions in the LHC. It's energy that is important, and regarding the energy levels of the LHC, it's very small compared to the collisions in the universe.
First of all, it's mostly PR. I'd not even call it "mini big bangs" because there is great difference between now and then - now it's a tiny droplet of quark-gluon plasma surrounded by (comparably to its size) vast amount of vacuum, while during big bang there was no vacuum around, all the universe was full of such matter and it was the energy contained in it that probably made the universe expand.
So well... the bulk of the universe by then had some temperature, and there is nothing in the today's universe capable of creating such high temperature in bulk matter ... including the LHC.
Particle collisions even more energetic than what happens in LHC are fairly common in the universe.
If I understand you correctly, the comparison with the big bang is overrated. The LHC is incapable of creating such a high temperature (in bulk matter!), and you confirm that collisions of particles with higher energies are a common thing in the universe.

All right, I will use the temperature, PR and the usual "low-energy-level of the LHC"-argument to counter critics. :D

Thanks again!

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