Questioning the "Cosmic Ray" safety defense of CERN's LHC

1000000monkeys

Whenever the safety of CERN's LHC is questioned, physicists point out that particle accelerator's are safe because cosmic rays are constantly hitting the Earth's atmosphere at similar (and greater) energies than any human-made device.

For example, this NYTimes article:

The safety group, however, pointed out that cosmic rays have produced equally energetic collisions with the Earth and other objects in the cosmos over and over again.

Another example, this Daily Show clip.

However, many articles about particle accelerators stress that some exotic subatomic particles may not have existed since the big bang.

For example, this National Geographic article:

Exotic fundamental particles—some of which likely haven't existed since the early moments after the big bang—are created in the high-energy crashes.

Isn't this a contradiction? If cosmic rays regularly act in a way similar to particle accelerators, then particle accelerators can't possibly create particles that haven't existed since the beginning of the universe. Right?

The argument about particle accelerators being dangerous goes something like this:

D1. There might be some rare particle or phenomenon (e.g. a Stranglet, Magnetic Monopole, Mini Black Hole, or something science doesn't know about yet) that could have catastrophic consequences for Earth, humanity, etc.
D2. A particle accelerator could create this particle or phenomenon.
D3. Thus, particle accelerators could be dangerous.

The "Cosmic Ray" argument for the safety of particle accelerators is:

S1. Particle accelerators don't do anything that cosmic rays do all the time.
S2. We haven't seen any catastrophic results from cosmic rays.
S3. Thus, particle accelerators are totally safe.

However, if...

X1. Particle accelerators can create particle that haven't existed since the beginning of the universe, then
X2. Clearly they are doing something different than commonplace cosmic rays.
X3. Thus, the premise S1 is false.

Thoughts on this? Am I missing something?

Is the "Cosmic Ray" defense spurious?

Enkidu

No it isn't spurious. The Natural Geographic article saying that particle accelerators will create particles not seen since the Big Bang is an exaggeration, as is typical in media reporting. The particles created in the LHC are often created by cosmic rays in the upper atmosphere.

1000000monkeys

Enkidu wrote: »

The Natural Geographic article saying that particle accelerators will create particles not seen since the Big Bang is an exaggeration, as is typical in media reporting. The particles created in the LHC are often created by cosmic rays in the upper atmosphere.

Thanks for the response, Enkidu. However the claim that Particle Accelerators can or might create particles that haven't previously existed is such a common claim—by scientists as well as by the "media"—that I'd really like for more verification that it is a completely untrue "exaggeration."

Below are some examples of this claim made in science publications, academic journals, and even in an announcement put out by one the groups doing experiments at CERN's LHC(!):

This Live Science article.

B mesons, which have both antimatter and matter packed inside them, were thought to have been common just after the Big Bang theorized to have created our universe, but are now thought not to occur in nature. Scientists can create them, and other exotic particles, only in energetic collisions in particle accelerators like LHC.

This Academic Journal article:

. There, the Large Hadron Collider (LHC) will smash protons together with such force that it could release showers of subatomic particles that haven’t existed since the big bang. S

And this announcement from CMS (Compact Muon Solenoid) at CERN.

The LHC accelerates protons to nearly the speed of light and then smashes them together inside detectors like CMS some 40 million times a second to produce fantastic particles, many of which haven’t been around since the Big Bang.

If these statements are UNTRUE and Cosmic Rays regularly create these particles, could someone please explain and verify it? Links, evidence, or the origins of your knowledge would be useful. Thanks!

Enkidu

1000000monkeys wrote: »

Below are some examples of this claim made in science publications, academic journals, and even in an announcement put out by one the groups doing experiments at CERN's LHC(!):

This Live Science article.



This Academic Journal article:

Neither of those are academic articles. One was written by a science writer (science focused journalist) and the other by a freelance journalist. They are not scientific statements.

And this announcement from CMS (Compact Muon Solenoid) at CERN.

Again this is the unfortunate inaccurate nature of media coverage of science even in press releases. However it's better if I respond to this. Again it's a press release to the public, not a scientific article itself.

If these statements are UNTRUE and Cosmic Rays regularly create these particles, could someone please explain and verify it? Links, evidence, or the origins of your knowledge would be useful. Thanks!

Particle accelerators have always been a way of gaining controlled access to the phenomena already present in cosmic rays. "Particles not seen since the Big Bang" is just an exaggerated (often for the purpose of gathering interest) way of expressing the fact that the LHC will probe energies uncommon for this period of the universes, only naturally occurring in cosmic rays.

As for the proof, you could work it out yourself. The typical speed of a particle in some cosmic rays is 20 - 50 times greater than the energy in the LHC and usually consist of hadrons (the constituents of the cosmic ray), just like in the LHC, slamming into other hadrons (atomic nuclei in Earth's atmosphere), just like in the LHC. Cosmic rays are high-energy hadron collisions, 20-50 times higher than the L.H.C. There is no difference between them.

Although if you want papers stating this fact explicitly I can post a few.

opinion guy

Epic username OP

Lisandro

Without examining the specific claims that are made about "exotic particles" and the like, the miniature black hole/general dangerous object scare is one I've encountered before, and I can see why the popular imagination would be scared. It is, however, completely bogus. The amounts of energy required to generate something to endanger the security of the planet are huge, way beyond the scale of a particle accelerator. In the words of Michio Kaku (who despite being a very intelligent figure in the world of physics is also a notorious hype-monger), the energy in a miniature black hole is not even enough to spark a lightbulb. If there were any dangers whatsoever with the particle accelerator, a significant section of the scientific community would oppose the LHC and would do so very publicly indeed.

The cosmic ray defence actually isn't needed; we would be assured of the LHC's safety even if we didn't have that criterion. If we consider the black hole scare again for a minute, we must note that an Earth-mass black hole requires a phenomenal amount of energy to form, a miniature black hole just doesn't lead to that. You can't even use the analogy of a nuclear reaction, because nuclear reactions can only be sustained because matter is converted to energy; otherwise neutrons colliding with uranium would amount to nothing more than particle scattering. The bottom line is that we couldn't trigger such a disaster with a particle accelerator, even if we wanted to!

krd

Lisandro wrote: »

If we consider the black hole scare again for a minute, we must note that an Earth-mass black hole requires a phenomenal amount of energy to form, a miniature black hole just doesn't lead to that.

Would it be able to swallow neutrinos?

If it could swallow neutrinos, and not evaporate through Hawking radiation, wouldn't it gain in size very quickly.

Then move on to protons, and then bigger atoms, then large rocks and anything it can swallow. Eventually getting around to us.

Lisandro

krd wrote: »

Would it be able to swallow neutrinos?

If it could swallow neutrinos, and not evaporate through Hawking radiation, wouldn't it gain in size very quickly.

Then move on to protons, and then bigger atoms, then large rocks and anything it can swallow. Eventually getting around to us.

That doesn't follow, if that were the case, we would be getting closer and closer to being swallowed by the black hole at the centre of the galaxy, which it's established even by classical arguments isn't going to happen. Even then, the gravitational flux from the black hole is nowhere near enough to attract enough matter to be able to overcome interatomic forces and quantum effects. What's more, it's generally accepted that the smaller the black hole, the faster it evapourates and that if the LHC were capable of generating miniature black holes, they wouldn't be any worse than ones possibly generated by cosmic rays interacting with the upper atmosphere. No matter what way it's viewed, the ever-expanding black hole argument just doesn't hold water.

krd

Lisandro wrote: »

That doesn't follow, if that were the case, we would be getting closer and closer to being swallowed by the black hole at the centre of the galaxy, which it's established even by classical arguments isn't going to happen.

Does it swallow neutrinos?

And it's also swallowing light.....Wouldn't that contribute to its' mass?

And I'm fully aware it's not expanding and sucking in the entire galaxy.

Lisandro

krd wrote: »

Does it swallow neutrinos?

I assume so, what precise contribution it would make to the black hole's mass, I'm not entirely sure, but it wouldn't be significant compared to the rest of the black hole's mass. We are talking about weakly interacting elementary subatomic particles here.

krd wrote: »

And it's also swallowing light.....Wouldn't that contribute to its' mass?

Depends on the interaction.

krd wrote: »

And I'm fully aware it's not expanding and sucking in the entire galaxy.

Which is why the exact same principle applies to miniature black holes. Their gravitational attraction on surrounding particles is infinitessimal.

krd

Lisandro wrote: »

I assume so, what precise contribution it would make to the black hole's mass, I'm not entirely sure,

I'm not really sure either. You never really think about neutrinos - but their is a steady flux anywhere near a star (I'm not going to grab the numbers - but it's a lot of neutrinos - it's in the millions per centimeter per second on earth)

but it wouldn't be significant compared to the rest of the black hole's mass. We are talking about weakly interacting elementary subatomic particles here.

Depends on the interaction.

Yes, they're weakly interacting. But, for a black hole - even a really tiny one - if the hole is in the path of the flux, I don't see any reason why or how the neutrinos could escape. They would fly in, and I don't see how they could fly out again.

For the neutrinos not to be swallowed, they'd need to be repelled. Though for mini-black holes the evaporation may happen faster than the neutrinos could be absorbed. There may even be other rules. The black hole may become unstable and become something else.

The idea of evaporation, either it keeps evaporating into infinity or at some point the interior of the black hole becomes unstable and it gives a burst of light or even becomes something else.

Which is why the exact same principle applies to miniature black holes. Their gravitational attraction on surrounding particles is infinitessimal.

That is if mini-black holes can exist. The idea of primordial black holes is they started large, and then evaporated. There may be reasons they can't exist. Like if black holes reach a critical size in the gravitational field of other bodies, it might be enough to make them unstable. If they sprung a leak - they might explode - like sticking a pin in a child's balloon. They may just lose stability at smaller sizes for other reasons.

No one has seen them explode - there may not be that much energy when they do. Maybe someone will figure out a signature radiation for them, and we'll start seeing them everywhere.

Then there's the idea of quantum foam. That in the foam their can be quantum fluctuations that cause ripples and wormholes in gravity. But where this idea seems to be wrong - there should be a noticeable broadening of the spectral lines from far away astronomical bodies (that's what I think at least). And Fermi labs recently observed bursts from a super nova, and they found no time difference in the arrival of the photons. If the foam was there, some of the photons should have taken slightly longer to get here.

So, there could be a reason, that at the level of min-black holes, gravity is smooth and they can't exist.

Lisandro

To be honest, it's inconsequential. If there were ever a danger of things getting out of hand, it would have surfaced long before now.