Ring of Antimatter Found in Earth's Orbit

The earth has a ring of antimatter encircling it, says newdata from the Pamela space satellite, a multinational project aimed at studying the planet’s magnetosphere. The discovery has fueled speculation that the antimatter might someday be harvested to power advancedspacecraft.

The antimatter particles are antiprotons—mirror opposites of regular protons (antimatter has similar properties to regular matter, just with opposite charge and spin). The antimatter is a few hundred miles up, in a ring near one of Earth’s Van Allen belts, which collect charged particles created or trapped by the planet’s magnetic field.

It was as challenge for the Pamela satellite to find the antiprotons in the Van Allen belt, a zone where high-energy particles are common. But the effect of antiprotons is unmistakable when it collides with normal matter, since both annihilate each other instantly, producing a measurable amount of energy and certain charged particles. Pamela discovered the number of annihilations taking place in the Van Allen belt was about 1,000 times higher than in typical space.

Now that we know there’s a potential jackpot of antimatter in orbit, what good is it? Considering researchers spend incredible sums of money and energy creating antimatter here on Earth, the idea of simply collecting it is extremely tempting. However, there are serious challenges standing in the way. Even if we could create some kind of craft or tool capable of harvesting the antiprotons in orbit, there still isn’t a way to reliably contain them. The longest time that scientists have been able to contain antimatter is about 17 minutes.

Still, that 17 minutes is much longer than previous times, and if advances keep pace, it’s possible the technology for harvesting and containing antimatter could become available in the future. Since, in an annihilation, the entire mass of both the antimatter and matter gets converted to energy, it’s the most efficient fuel in the universe, and many have speculated that antimatter will eventually fuel advanced spacecraft.

"One of the main uses of antimatter would be a starship," scientist Michio Kaku told PCMag after an antimatter discovery last fall. "Because you want concentrated energy. And you can't get more concentrated than antimatter."

Both NASA and DARPA have loose plans for antimatter-fueled starships. While those projects are a long way off, the Pamela discovery provides a glimmer of hope that they’ll someday become realized.