We don't often encounter species that produce their own light here on land. But about 1,000 to 1,500 feet beneath the ocean surface, in a region known as the deep scattering layer, there can be so much bioluminescence that the sea looks as if it is twinkling with blue stars.

"The only light many of these animals see is made from other organisms," said Matt Davis, an ichthyologist at St. Cloud State University in Minnesota.

Fish use bioluminescence to communicate with one another, as a way to lure prey and even as a defense mechanism. Bioluminescence is so useful to underwater creatures that it turns out it evolved independently at least 27 times in marine fish alone, said a study in PLOS One.

Monumental piece of ancient Petra found

Archaeologists have been combing the ancient city of Petra in southern Jordan for at least two centuries. Now, with drones and satellite imagery, they have discovered new features, including a monumental platform of nearly 30,000 square feet, or roughly half a football field. Pottery shards nearby date from the second century B.C. through the sixth century A.D.

These bees reproduce without males

The female Cape honeybee is a South African renegade: She may escape her queen's control, take over other colonies and reproduce asexually, without any help from males. Scientists examining the bee genomes concluded that evolution has clearly favored asexual reproduction in the Cape honeybee. But no one knows why.