Installed by a company called SkyCool Systems, they are the first of a new breed of cooling technologies that radiate heat out through the atmosphere, lowering nearby air temperatures by about 10°F.
Radiative cooling is what happens when the electromagnetic waves we call heat leave an object. It's the phenomenon that puts you at risk for heat stroke in the desert during the day, and hypothermia at night; the absorbed heat evacuates the landscape at sundown, and without any moisture to trap it, leaves through Earth's atmosphere into outer space.
A UCLA scientist reasoned that if a certain spectrum of warming rays is radiated out to the atmosphere during the day, it would cool whatever it left, potentially offering an alternative to traditional air conditioning.
An estimated 7% of global greenhouse gas emissions are generated through cooling systems, both for homes and transport, but as global temperatures continue to climb, the use of cooling systems for homes and businesses is expected to triple over the coming years.
SkyCool's radiative panels can absorb all the heat-producing light from the sun, and rather than sending it back into the swirling cauldron of gasses that are heating the planet, expels it out into space.
Aaswath Raman, a materials scientists at the University of California LA, discovered that radiative cooling technologies like panels and special reflective paints had been investigated before but then abandoned as impossible.