Learn how to use, choose and shop for grow lights -- whether you're tending to houseplants or starting your own seeds.

When we go out in the sun, our body tries to defend itself from the harmful ultraviolet (UV) rays in sunlight by producing ... so it can detect UV – a wavelength of light which we cannot see ...

Near-infrared light (NIR) is an invisible part of the solar spectrum that makes up 50 per cent of sunlight and plays ... near-infrared light with a wavelength of 850 nanometers.

The same shifts in frequency and wavelength are also observed for light coming from stars in distant galaxies. By comparing the light from distant stars with the spectrum of light from our Sun it ...