Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

Some experts (and non experts) have called LHC the most powerful microscope in the world. I am wondering, what does the LHC magnify? Or is calling it a microscope just wrong and misleading?

share|improve this question
add comment

2 Answers

up vote 7 down vote accepted

Well, it is a microscope if the word is understood in a generalized sense that it allows us to learn about microscopic structure of some stuff. To understand the connection one should first recall how good old optical microscopes work.

The principle is really quite simple, you throw some stuff at the object you are interested in and observe what happens. In the old setting, you throw photons (i.e. light) which then come back to you and you record where they landed (obviously you also need to use some optical methods to actually magnify stuff). This then shows you the structure of the microscopic matter. But at certain point this stops working since visible light has wavelength of roughly $500 \,\rm nm$ so it can't really detect anything smaller than this.

So, to increase resolution, you start throwing smaller things (with smaller wavelength or equivalently bigger energy) at stuff. So you try electrons and neutrons, even photons, but this time with shorter wavelength (e.g. gamma rays). But as you come down to this minute level of atomic and subatomic scales, quantum properties will manifest strongly and the good old approach of throwing photons and seeing what comes back stops working.

At quantum level you can only predict probabilities. E.g. that if you hit some object with a photon, you can calculate the probability that certain particle (e.g. pion) will be created and fly off into the given direction. There is really no way to tell beforehand. Also, at these energies new particles will be abundantely created since you get to energies above the mass of those particles. Therefore at these scales (and LHC is very deeply in these scales), microscope really means collider.

share|improve this answer
add comment

I would add as an answer to "what does the LHC magnify" : it magnifies the microcosm.

Even though it is only probabilities that we can measure, the range is accessible, and the higher the energy, the finer the details of the region explored.

share|improve this answer
    
Can we say that it magnifies the vacuum then ? –  Revo Aug 18 '11 at 19:30
    
@Revo Sure, with enough energy we can start extracting pairs out of the vacuum sea, so it is "seeing " the structure of the vacuum. What is your problem? If you can take a picture as with an electron microscope? The "picture" is convoluted by the levels of detection methods needed, and as it is probabilistic will be quite fuzzy, but yes, it is a "picture". –  anna v Aug 19 '11 at 4:11
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.