The coldness of slot outer space is also an extremely important renewable energy resource," a researcher says.

It likely goes without saying, but of all the energy solar panels generated last year, none of it was produced at night. New research is showing that doesn't have to be the case.

Researchers at Stanford modified commercially available solar panels to generate a small amount of electricity at night by exploiting a process known as radiative cooling, which relies on, no lie, the frigid vacuum of space. The research was published in early April in Applied Letters in Physics.

"We tend to think of the sun as the important renewable energy resource," said Shanhui Fan, the lead researcher on the project. "The coldness of outer space is also an extremely important renewable energy resource