"how do you suppose it lives when we leave it? Each is planted most tenderly in its own little pit. The pits are filled with smooth ovals of chromoplastic. Light turns them white. You can see them glistening in the dawn if you look down from a high place. White reflects. But when Old Father Sun departs, the chromoplastic reverts to transparency in the dark. It cools with extreme rapidity. The surface condenses moisture out of the air. That moisture trickles down to keep our plants alive."
Pretty clever idea. But a real-life (not fictional) materials scientist named Aaswath Raman at UCLA has done fiction one better with this nano photonic radiative cooler metamaterial (start around 6:50 for more background):
(Aaswath Raman nano photonic radiative cooler)
From fundamental thermodynamic considerations, in order to convert heat to usable work, it is important to have a heat source with a temperature that is as high as possible, and to have a heat sink with a temperature that is as low as possible. The vast majority of energy conversion processes at the moment use our ambient surroundings on Earth itself, with a temperature of approximately 300 K, as the heat sink. On the other hand, the universe, with a temperature of approximately 3 K, represents a much better heat sink. The ability to harness the coldness of the universe could therefore have broad implications for energy technologies in general, and represents an important emerging frontier in renewable energy research.
The ability of photonic structures such as metamaterials to control the behavior of electromagnetic waves is essential to effectively harness the coldness of the universe. Earth's atmosphere is largely transparent to electromagnetic waves in the wavelength range of 813 μm. This wavelength range coincides with the spectral peak for black body radiation at 300 K. Thus, any object, when exposed to the sky, can radiate its heat out in a process known as radiative cooling (Fig. 1a) and passively reach sub-ambient temperatures.
This natural phenomenon has been implemented and studied at night for centuries. However, to improve the thermodynamic efficiency of energy technologies in general, and for cooling applications in particular, it would be far more useful to enable the same cooling effect during the day. The challenge here is that a sky-facing object faces the sun directly during daylight hours. For this purpose, then, one would need to create a structure that reflects the entire solar spectrum very well, while at the same time generating strong thermal radiation in the 813 μm wavelength range.