A question about the LHC

  • #1
Dear readers
for start thank you for your patience in readind this letter
i was readind a book about higgs and in chapter 8 the author discribed this following event :
as CERN was making its plans for the LHC public was worried for the security of the LHC
One peoples fear was from the experiments a unusual particle could be <<created>> and it could reach the centre of the Earth cayzing the tempreture to <<heat up >>... The author said that this fact would make earth have the size of a football . my question is why ?
 

Answers and Replies

  • #2
Ryan_m_b
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Welcome to the forums. The concern was surrounding the creation of micro black holes, CERN's website has a section on safety considerations that you may be interested in reading. A relevant point from that page:
Micro black holes said:
Nature forms black holes when certain stars, much larger than our Sun, collapse on themselves at the end of their lives. They concentrate a very large amount of matter in a very small space. Speculations about microscopic black holes at the LHC refer to particles produced in the collisions of pairs of protons, each of which has an energy comparable to that of a mosquito in flight. Astronomical black holes are much heavier than anything that could be produced at the LHC.

According to the well-established properties of gravity, described by Einstein’s relativity, it is impossible for microscopic black holes to be produced at the LHC. There are, however, some speculative theories that predict the production of such particles at the LHC. All these theories predict that these particles would disintegrate immediately. Black holes, therefore, would have no time to start accreting matter and to cause macroscopic effects.

Although theory predicts that microscopic black holes decay rapidly, even hypothetical stable black holes can be shown to be harmless by studying the consequences of their production by cosmic rays. Whilst collisions at the LHC differ from cosmic-ray collisions with astronomical bodies like the Earth in that new particles produced in LHC collisions tend to move more slowly than those produced by cosmic rays, one can still demonstrate their safety. The specific reasons for this depend whether the black holes are electrically charged, or neutral. Many stable black holes would be expected to be electrically charged, since they are created by charged particles. In this case they would interact with ordinary matter and be stopped while traversing the Earth or Sun, whether produced by cosmic rays or the LHC. The fact that the Earth and Sun are still here rules out the possibility that cosmic rays or the LHC could produce dangerous charged microscopic black holes. If stable microscopic black holes had no electric charge, their interactions with the Earth would be very weak. Those produced by cosmic rays would pass harmlessly through the Earth into space, whereas those produced by the LHC could remain on Earth. However, there are much larger and denser astronomical bodies than the Earth in the Universe. Black holes produced in cosmic-ray collisions with bodies such as neutron stars and white dwarf stars would be brought to rest. The continued existence of such dense bodies, as well as the Earth, rules out the possibility of the LHC producing any dangerous black holes.
 
  • #3
hi thank you for answering but that isnt what i was looking for ...
i gave the higgs and LHC example just so i can explain my question
my general question is why if an object (or planet) is heated up into very high tempreture its size decreases so much .. Or in my example why if earth becomes so hot it will have the size of a football ....:rolleyes:
 
  • #4
Ryan_m_b
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Science Advisor
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The most obvious answer is that when things are compressed to a smaller size the temperature increases. A micro black hole would absorb matter and grow as it does so shrinking the Earth into a small hot accretion disk. Alternatively you could have been reading about strangelets which may operate in a similar manner.
 
  • #5
:confused:
Yeah but your answer is if the obgect is decreased ...
my question is why in high tempretures object decrease their size ? ..
thank you
 
  • #6
Ryan_m_b
Staff Emeritus
Science Advisor
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They don't, I think your confusion stems from a misunderstanding in what you read originally. It's not:

The increase in temperature that leads to the size decrease

it is

The size decrease that leads to the increase in temperature

Does that make sense?
 
  • #7
yes ...
thank you very much and sorry for my confusion ..
 
  • #8
Ryan_m_b
Staff Emeritus
Science Advisor
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yes ...
thank you very much and sorry for my confusion ..
No worries :smile:
 

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