Encyclopedia > Protoplanetary disc

Article Content

Protoplanetary disc

A protoplanetary disc (proplyd) is a disc of dust and gas which orbits a protostar, within a solar nebula. Such discs eventually condense into either asteroid belts, moons, or planets.

Featured Article

Urethra

... long and opens in the vulva between the clitoris and the vaginal opening. In the human male, the urethra is about 8 inches (200 mm) long and opens at the end of th ...