A hole in the LHC's vacuum bubble safety argument

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Discussion Overview

The discussion revolves around the safety arguments related to the Large Hadron Collider (LHC), specifically focusing on the potential risk of vacuum bubble formation during collisions. Participants examine the validity of claims made in safety reports and question the adequacy of existing safety reviews in addressing this risk.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants highlight that the LHC Safety Assessment Group (LSAG) claims previous reports have ruled out the risk of vacuum bubble formation, yet they note that the earlier report did not address this specific risk.
  • Questions are raised about the existence of theories that would predict vacuum bubbles from LHC collisions but not from higher-energy astrophysical processes.
  • One participant references Stephen Hawking's concerns regarding the Higgs potential and the possibility of catastrophic vacuum decay, suggesting it as a relevant issue.
  • Another participant argues that ultra-high cosmic rays (UHCR) have much higher luminosity than the LHC and pose no threat, implying that the LHC's risks are overstated.
  • There are claims that the safety report fails to adequately address the differences in luminosity and density between LHC collisions and cosmic ray events.
  • Some participants challenge the validity of arguments that dismiss concerns by comparing them to implausible scenarios, indicating a need for serious consideration of all potential risks.
  • Discussions include the need for clarity on why certain conditions, such as luminosity, are not considered a safety issue in the context of vacuum bubbles.

Areas of Agreement / Disagreement

Participants express differing views on the adequacy of the safety reports and the validity of the arguments presented. There is no consensus on whether the risks associated with vacuum bubbles have been sufficiently addressed or if the comparisons to cosmic ray collisions are valid.

Contextual Notes

Participants note that the discussion is limited by the requirement to reference only published material, which may restrict the exploration of certain theoretical concerns. Additionally, the debate highlights the complexity of comparing collision energies and their implications for safety.

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A hole in the LHC's vacuum bubble safety argument

One of the four specific risks considered in the most recent official safety review for the Large Hadron Collider (LHC) is the possibility that LHC collisions could trigger a transition to a lower-energy vacuum state. The current review by the LHC Safety Assessment Group (LSAG) [2] asserts that this risk was ruled out in the earlier report of the LHC Safety Study Group (LSSG) [1]. The conclusion of the LSAG's report states:
In the case of phenomena, such as vacuum bubble formation via phase transitions or the production of magnetic monopoles, which had already been excluded by the previous report [1], no subsequent development has put these firm conclusions into question.

It should be noted, however, that the LSSG's report considers only the three specific risks of strangelets, black holes, and magnetic monopoles. The LSSG's report includes no mention whatsoever of the possibility of vacuum bubble formation and includes no data relevant to the vacuum bubble safety argument briefly outlined in the LSAG's report.

References

[1] Blaizot J P et al (LSSG), 2003, Report of the LHC Safety Study Group, CERN-2003-001 <http://cds.cern.ch/record/613175/files/CERN-2003-001.pdf>

[2] Ellis J et al (LSAG), 2008, J. Phys. G: Nucl. Part. Phys. 35 115004 (arXiv:0806.3414) <http://arxiv.org/abs/0806.3414>
 
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So, it's a re-confirmation review?
 
Where are theories about vacuum bubbles that would need more safety reviews? In particular, which theory would suggest vacuum bubbles from the LHC but not from astrophysical collision processes at much higher energies?

Note that only published material counts as acceptable reference here.
 
I think (s)he was trying to say the same things referred to in Sec.3 of the review (s)he posted.
 
mfb said:
Where are theories about vacuum bubbles that would need more safety reviews? In particular, which theory would suggest vacuum bubbles from the LHC but not from astrophysical collision processes at much higher energies?

Note that only published material counts as acceptable reference here.

Your argumentation isn't correct. You already exclude what has the right to be in the report; and what can be discussed and possibly declared as not a safety issue by the report.

Anyway one example of an issue with the Vacuum I can think of is what Stephen Hawking mentioned:

"The Higgs potential has the worrisome feature that it might become metastable at energies above 100 billion GeVs. This could mean that the universe could undergo catastrophic vacuum decay, with a bubble of the true vacuum expanding at the speed of light. This could happen at any time and we wouldn't see it coming." - http://www.popularmechanics.com/sci...-said-about-destroying-the-universe-17192502/


--

But just like the answer you (mfb) already mention in your comment ... all the pro-safety arguments lead to the existence of Ultra-high-cosmic rays (UHCR), which overrule by far what is going on at the LHC, and they don't cause any threatening damage, so we are safe. Such as explained with this analogy in the article:

"Imagine that somebody hands you a piece of paper and says, 'This piece of paper has the potential to spontaneously combust,' and so you might be worried," Mack says. "But then they tell you 20 years ago it was in a furnace." If it didn't combust in the furnace, it's not likely to combust sitting in your hand.

--

The only thing that is missing in the safety report, is the fact that the luminosity and density is much higher in the lhc than for cosmic ray collisions in the open air by a factor of 109, although this number depends on your frame of reference, as discussed in an other topic here on the forum.

It would be an asset to the Safety report if they would officially outline why density is not an issue and at what point it would be an issue, just like the article on Vacuum Bubbles does.
 
Michel said:
Your argumentation isn't correct. You already exclude what has the right to be in the report; and what can be discussed and possibly declared as not a safety issue by the report.
The purpose of the report is to analyze safety concerns. The analysis has to restrict itself to serious concerns - it cannot cover every possible "the LHC could create dangerous magical fairies" concern, and we cannot discuss them either. Therefore we restrict discussions here to published material.
Michel said:
The only thing that is missing in the safety report, is the fact that the luminosity and density is much higher in the lhc than for cosmic ray collisions in the open air by a factor of 109, although this number depends on your frame of reference, as discussed in an other topic here on the forum.
And as discussed in detail in this topic, this is not true.
This is so obvious to physicists that they did not bother discussing it.
 
I have never encountered a theory where "the LHCcould create dangerous magical fairies" or such.

Besides that the OP was about vacuum bubbles, so is it your intention to mock Stephen Hawkins by resourcing to that kind of argument?

It has become a stereotypic intimidation technique where by using this type of ridicule people get to be pushed into a corner with arguments that you make up yourself.

Once again your style of argumentation is not correct.
 
Michel said:
I have never encountered a theory where "the LHCcould create dangerous magical fairies" or such.
I used it as placeholder for everything with a similar likelihood. Producing earthquakes, producing a powerful weapon in some way, producing radiation to somehow influence some persons in some way (didn't get the details) - yes all those weird ideas and many more exist.
Besides that the OP was about vacuum bubbles, so is it your intention to mock Stephen Hawkins by resourcing to that kind of argument?
Where did Stephen Hawking talk about the relation between vacuum bubbles and the LHC? 100 billion GeV is 10 million times above the LHC energy.
 
Michel said:
The only thing that is missing in the safety report, is the fact that the luminosity and density is much higher in the lhc than for cosmic ray collisions in the open air by a factor of 109

OTOH, high energy cosmic rays impinge onto gazillion of stars, planets and lesser specks of dust all over the Universe for some 13+ billions of years already. Cumulatively all these ongoing events have vastly higher luminosity than LHC at any given instant.
 
  • #10
mfb said:
I used it as placeholder for everything with a similar likelihood. Producing earthquakes, producing a powerful weapon in some way, producing radiation to somehow influence some persons in some way (didn't get the details) - yes all those weird ideas and many more exist.
Where did Stephen Hawking talk about the relation between vacuum bubbles and the LHC? 100 billion GeV is 10 million times above the LHC energy.

You are right.
 

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