Photovoltaic cells, the basic unit of solar power systems, turn light into electricity. But fueling photovoltaics with sunlight isn't always practical. MIT scientists came up with a way around this issue: They found a really efficient way to turn heat into light.

Scientists have known for awhile that this is possible, but the MIT scientists figured out how to use a certain type of pitted material to force heat into generating the sort of wavelengths the PV cells love the most. Basically, it's as if this material turns grass into chocolate: both are forms of energy, but humans like to consume the latter a whole lot more than the former.

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Researchers have used this technology to make a tiny power generator that runs on butane — basically a cigarette lighter that can charge your phone. They’ve also made a device that can power spaceships headed far away from the sun, which … should we be worried that this is what MIT scientists are working on?

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