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Physics/Large Hadron Collider


Hi! I was just checking up the specs of LHC and they said that it accelerates particles to 99.97% lightspeed. And it is 27km long. These accelerators being so long makes them really expensive and you need to procure a lot of space. So could one that accelerates particles to 99.97% lightspeed be built 1 kilometer long and still function the same way as LHC? I chose one kilometer because my extended family owns a field and 1 kilometer is the largest ring shaped thing you can build under it.

Hello Mika,

The website below does a very good job of answering this question.

One of the key parts of that discussion is that for the particles to go in a circle, there must be a centripetal acceleration on them. That centripetal force is given by
Ac = v^2 / r. So for a given speed, the required centripetal acceleration is inversely proportional to radius. And therefore the magnitude of the synchrotron radiation problem is inversely related to the radius. Also, it is not unimportant that the cost of providing centripetal acceleration is inversely related to the radius.

I hope this helps,


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Steve Johnson


I would be delighted to help with questions up through the first year of college Physics. Particularly Electricity, Electronics and Newtonian Mechanics (motion, acceleration etc.). I decline questions on relativity and Atomic Physics. I also could discuss the Space Shuttle and space flight in general.


I have a BS in Physics and an MS in Electrical Engineering. I am retired now. My professional career was in Electrical Engineering with considerable time spent working with accelerometers, gyroscopes and flight dynamics (Physics related topics) while working on the Space Shuttle. I gave formal classroom lessons to technical co-workers periodically over a several year period.

BS Physics, North Dakota State University
MS Electrical Engineering, North Dakota State University

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