Teams working on two continents have marked similar milestones in their respective efforts to master nuclear fusion.

Scientists at the International Thermonuclear Experimental Reactor in southern France took delivery Thursday of the first part of a massive magnet so strong its American manufacturer claims it can lift an aircraft carrier.

And in Massachusetts, MIT researchers and a private company announced this week that they, too, have successful tested the world’s strongest high temperature superconducting magnet that may allow the team to leapfrog their rivals in the race to build a `sun on earth.’

Proponents of fusion say it offers a clean and virtually limitless supply of energy, though efforts to harness it have been ongoing for nearly a century.