Science: Electron Fattener

With a flashing of 84 rectifier tubes and a chugging of six great electromagnets, the world's biggest (300 million volt) betatron started operating last week at the University of Illinois. Betatrons look something like cyclotrons, but instead of spinning protons or heavier particles, they spin lightweight electrons.

In the Illinois betatron, the electrons circle a nine-foot, doughnut-shaped tube 140,000 times in four one-thousandths of a second, reach a speed only one-millionth part less than the speed of light. In accordance with Einstein's laws of relativity, the speed increases their mass 600 times. (The last few m.p.h. come hardest. Theoretically, if they...

Want the full story?

Subscribe Now


Get TIME the way you want it

  • One Week Digital Pass — $4.99
  • Monthly Pay-As-You-Go DIGITAL ACCESS$2.99
  • One Year ALL ACCESSJust $30!   Best Deal!
    Print Magazine + Digital Edition + Subscriber-only Content on

Learn more about the benefits of being a TIME subscriber

If you are already a subscriber sign up — registration is free!