Fireflies’ summer evening light shows are a delight for humans, but for the insects they are a crucial mating ritual – and human-caused light pollution is a buzz kill.
The sea is blue because of the way water absorbs light, the way particles in the water scatter light, and also because some of the blue light from the sky is reflected.
Flickr/Fiona Paton
Photons stream from the sun and interact with all matter on Earth. Depending on what the light touches, some of the photons will get absorbed or soaked up. And some will bounce back.