Search.com Reference combines the Wikipedia online encyclopedia, a dictionary, and links to related resources around the Web to provide you with a complete Reference for thousands of topics.
Today's Featured Article
An
H II region is a cloud of glowing gas, sometimes several hundred
light years across, in which
star formation is taking place.
Young, hot, blue stars which have formed from the gas emit copious amounts of
ultraviolet light, ionising the
nebula surrounding them. H II regions may give birth to thousands of stars over a period of several million years. In the end,
supernova explosions and strong
stellar winds from the most massive stars in the resulting
star cluster will evaporate the gases of the H II region, leaving behind a cluster such as the
Pleiades. H II (pronounced "H two") regions are named for the large amount of
ionised
atomic
hydrogen they contain, referred to as
H II by
astronomers (H I being
neutral atomic hydrogen, and H
2 being
molecular hydrogen). H II regions can be seen out to considerable distances in the universe, and study of extragalactic H II regions is important in determining the distance and chemical composition of other
galaxies.
Read more about
H II region in Reference »
Recently featured:
Mahatma Gandhi –
Super Mario 64 –
Laal language
