# velocity speed records in particle accelerators? **URL:** \ **Category:** Factual Questions\ **Created:** [July 13, 2002, 12:27am UTC](https://boards.straightdope.com/t/velocity-speed-records-in-particle-accelerators/118723 "2002-07-13T00:27:24Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![ready29003](https://avatars.discourse-cdn.com/v4/letter/r/71e660/32.png) [@ready29003](https://boards.straightdope.com/u/ready29003)\ **Post date:** [July 13, 2002, 12:27am UTC](https://boards.straightdope.com/t/velocity-speed-records-in-particle-accelerators/118723/1 "2002-07-13T00:27:24Z")
In particle accelerators, what velocities are achievable? Is there a speed record for the fastest velocity achieved for particles in a particle accelerator? Such as the fastest velocity every achieved for an atom of lead or something? Have any particles ever been accelerated to within a significant percentage of the speed of light such that Einstein’s laws about mass increase becomes measurable? Anyone have any great book or web site recommendations that discuss experiments and theory relevant to my questions? ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [July 13, 2002, 1:13am UTC](https://boards.straightdope.com/t/velocity-speed-records-in-particle-accelerators/118723/2 "2002-07-13T01:13:56Z")
I think we got something moving something like 0.9997c ---
**Author:** ![douglips](https://avatars.discourse-cdn.com/v4/letter/d/e68b1a/32.png) [@douglips](https://boards.straightdope.com/u/douglips)\ **Post date:** [July 13, 2002, 4:44am UTC](https://boards.straightdope.com/t/velocity-speed-records-in-particle-accelerators/118723/3 "2002-07-13T04:44:44Z")
Since c is the fastest that things with mass can move, when talking about particle speeds usually the energy is used instead of the speed. The answer to how fast something goes in a particle accerator is c - e where e is some very very small number. I’m too lazy to actually do the math, so I’ll just point out that the [Oh My God particle](http://www.fourmilab.ch/documents/ohmygodpart.html) was going v = 0.9999999999999999999999951 c As for mass increase, it has absolutely been observed. A charged particle moving through a magnetic field will curve, the amount it curves depends on the mass and energy of the particle. If you look at the tracks in a [bubble chamber](http://rd11.web.cern.ch/RD11/rkb/PH14pp/node17.html) or other detector, you can calculate the mass of particles, and they act exactly as Einstein says they should. In addition, short-lived particles such as m particles live longer as observed in the particle detectors due to time-dilation, another of Einsteins predicted (and verified) effects. ---
**Author:** ![Pasta](https://avatars.discourse-cdn.com/v4/letter/p/ecccb3/32.png) [@Pasta](https://boards.straightdope.com/u/Pasta)\ **Post date:** [July 13, 2002, 5:19am UTC](https://boards.straightdope.com/t/velocity-speed-records-in-particle-accelerators/118723/4 "2002-07-13T05:19:38Z")
> [@](#): > > \*Originally posted by ready29003 \* > **In particle accelerators, what velocities are achievable? Is there a speed record for the fastest velocity achieved for particles in a particle accelerator?** The LEP collider at CERN holds the record. LEP reached a center of mass energy of 209 GeV, meaning its electrons and positrons had energies of 104.5 GeV. The corresponding speed: 0.999999999976c. The Tevatron at the Fermi National Accelerator Laboratory brings protons and antiprotons to even higher energies (1000 GeV), but since these particles are much heavier than LEP’s electrons and positrons, they actually have a lower speed (0.99999912c). > [@](#): > > **Have any particles ever been accelerated to within a significant percentage of the speed of light such that Einstein’s laws about mass increase becomes measurable?** Relativistic effects are measurable at energies well below these extremes. In fact, high energy physicists usually don’t think of relativistsic effects as “effects”. These phenomena are just part of “regular” physics. (It is actually rare that a high energy physicist does a particle-related calculation that does _not_ involve relativistic formulae.) ---
**Author:** ![SPOOFE](https://avatars.discourse-cdn.com/v4/letter/s/c5a1d2/32.png) [@SPOOFE](https://boards.straightdope.com/u/SPOOFE)\ **Post date:** [July 13, 2002, 10:35am UTC](https://boards.straightdope.com/t/velocity-speed-records-in-particle-accelerators/118723/5 "2002-07-13T10:35:51Z")
Quick question/hijack about the Oh-My-God particle… The link described it as having the energy of a brick falling on your toe. Is this an accurate description of what would happen if that particle hit, say, a human body? A rude bump and a bruise? Or would the much smaller size of the particle cause breaking of the skin? ---
**Author:** ![SPOOFE](https://avatars.discourse-cdn.com/v4/letter/s/c5a1d2/32.png) [@SPOOFE](https://boards.straightdope.com/u/SPOOFE)\ **Post date:** [July 13, 2002, 10:38am UTC](https://boards.straightdope.com/t/velocity-speed-records-in-particle-accelerators/118723/6 "2002-07-13T10:38:26Z")
Oh, nevermind, now that I think about it, it would probably go right through a person without losing too much of its energy…