LHC Dangers (really *only* stuff that's already happening?)

[Kaktus]

So I was wondering, I hear everywhere that what the LHC (or RHIC) is only doing what's happening all the time already with cosmic rays. Is that really so? Are the really doing NOTHING new here? Are they really just doing stuff that's already happening all the time? From what I understand, they smash different sorts of atoms together (don't quote me on it, it's what I vaguely picked up). For example I think in the RHIC they're using gold atoms. Now I'm wondering, I'm sure there are some atoms on Earth that don't occur anywhere else. Atoms that first had to be produced by humans, like Plutonium for example. Atoms that don't come in contact with cosmic rays, where you couldn't simply say "it's happening all the time in our atmosphere and on the moon. Nothing dangerous about it", because it's not. I'm sure there's something here I understand wrong so if someone here could please enlighten me as to why it is that the LHC or RHIC apparently aren't doing anything new I'd be really happy. If you for instance decided to smash two Plutonium atoms together, I'm sure that's something that doesn't happen anywhere else. But I don't know much about all this, and I just want to know why it's not dangerous and how apparently these accelerators aren't doing anything new.

 

[PeterDonis]

I hear everywhere that what the LHC (or RHIC) is only doing what's happening all the time already with cosmic rays.

What they mean is that the range of energies being explored at the LHC and RHIC are well within the range of energies of cosmic ray collisions (in fact the most energetic cosmic ray collisions are orders of magnitude more energetic than the most energetic collisions we can create in those colliders). The energy range is the key factor that determines what sorts of things can happen.

I'm sure there are some atoms on Earth that don't occur anywhere else. Atoms that first had to be produced by humans, like Plutonium for example.

That's probably true (at least, leaving out the possibility that there is other intelligent life out there that has also produced those atoms), but you have to remember that atoms, and even atomic nuclei, are low energy objects, at least as far as the differences in behavior that we are used to are concerned. At the energies being explored at the LHC and RHIC (let alone the energies in the most energetic cosmic ray collisions), all atoms and nuclei look the same--they're just a bunch of quarks and electrons, and the collisions that take place are between the quarks and electrons. The collisions don't care whether the quarks and electrons are inside hydrogen atoms or gold atoms or plutonium atoms or anything else; the same interactions will happen in any case. The only difference with heavier atoms is that there will be more of them per unit time; that's why the RHIC uses heavy ions, to be able to generate more collision events that they can study.

 

[Drakkith]

All atoms are made of the same components. When two cars smash into each other on the highway we don't question the physics just because the cars are different models. We understand that they are made up of similar materials and the physics doesn't change just because of the way they are put together. Similarly, we know that atoms are made up of different subatomic particles, and that some of these, the neutrons and protons, are themselves composed of smaller particles. So when we smash two atoms together, regardless of which specific atoms they are, we know that the physics is the same as any other collision between atoms. So too are the collisions between cosmic rays and our atmosphere. Sure, they might not be the exact same type of atoms as what we use in colliders, but the underlying physics is exactly the same.

Since we don't observe anything even remotely dangerous from cosmic rays, there is little reason to think that our own particle colliders are themselves dangerous.

 

[ZapperZ]

So I was wondering, I hear everywhere that what the LHC (or RHIC) is only doing what's happening all the time already with cosmic rays. Is that really so? Are the really doing NOTHING new here? Are they really just doing stuff that's already happening all the time? From what I understand, they smash different sorts of atoms together (don't quote me on it, it's what I vaguely picked up). For example I think in the RHIC they're using gold atoms. Now I'm wondering, I'm sure there are some atoms on Earth that don't occur anywhere else. Atoms that first had to be produced by humans, like Plutonium for example. Atoms that don't come in contact with cosmic rays, where you couldn't simply say "it's happening all the time in our atmosphere and on the moon. Nothing dangerous about it", because it's not. I'm sure there's something here I understand wrong so if someone here could please enlighten me as to why it is that the LHC or RHIC apparently aren't doing anything new I'd be really happy. If you for instance decided to smash two Plutonium atoms together, I'm sure that's something that doesn't happen anywhere else. But I don't know much about all this, and I just want to know why it's not dangerous and how apparently these accelerators aren't doing anything new.

You may start by reading this:

https://www.bnl.gov/rhic/docs/rhicreport.pdf

Zz.