John Roach
Antimatter-fueled rocket could approach light speed

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NASA
Researchers at NASA's Marshall Space Flight Center developed this sketch of a hypothetical antimatter rocket of the future.


A rocket ship, powered by smashing lumps of matter and antimatter together, could zip through space at about 70 percent the speed of light, according to a new study.
When traveling in such an antimatter-powered rocket ship, a trip from Earth to its closest stellar neighbor, Proxima Centauri, would take about 6 years, as it is located 4.2 light years away.
But before astronauts pack their bags for the voyage, one problem needs to be overcome: antimatter is in limited supply.
By one estimate, it would take the Large Hadron Collider a thousand years to make a single microgram of the stuff, MIT Technology Review’s arXiv blog notes.
Ronan Keane, a high school senior at Western Reserve Academy, and Wei-Ming Zhang, a senior research fellow at Kent State University, cast aside these supply concerns and performed a new set of calculations to determine how good an antimatter rocket could be.
One reason to do so, they note in the paper posted on Physics arXiv, is the potential of the fuel source:
The nominal energy released per kilogram of annihilating antimatter and matter is 9 x 1016 Joules — about two billion times larger than the thermal energy from burning a kilogram of hydrocarbon, or over a thousand times larger than liberated from a kilogram of fuel in a nuclear fission reactor.
The pair’s calculations were made with the help of software developed to better understand how particles behave at the LHC, which smashes together beams of protons and antiprotons.
The software, they note, allows for more sophisticated engine designs than previously possible.
The result is one that can propel a rocket ship at about 70 percent the speed of light, which is an improvement over the 33 percent speed of light reported by previous teams.
Such engines work by “using a magnetic field to deflect charged particles created in the annihilation ... So an important factor is how efficiently the magnetic field can channel these particles out of the nozzle,” the arXiv bog explains.
Now that such an engine appears possible, it’s time to start looking for the fuel. One place, the team suggests, is in outer space, where studies have shown large amounts are trapped in Earth's magnetic field.
For more information on the promises and limitation of the technology, check out the paper and blog.
For those still thinking about the trip to Proxima Centauri, consider this: as you approach the speed of light, time doesn't move as fast, a phenomenon known as the relativistic effect. That means even though the trip by Earth clock time would take about 6 years, it would only seem like 4.3 years.
--Via Technology Review

John Roach is a contributing writer for msnbc.com. To learn more about him, check out his website and follow him on Twitter. For more of our Future of Technology series, watch the featured video below.