W3(OH)

A region in the Milky Way galaxy where stars are being formed by the gravitational collapse of a cloud of gas and dust, surrounded by a giant cloud of methyl alcohol. Giant filaments of gas in this region emit as masers, in which molecules in the gas amplify and emit beams of microwave radiation in the same way as a laser emits beams of light.

The filaments of masing gas form giant bridges between maser spots in W3(OH); the largest is 463 billion kilometers long. The entire gas cloud appears to be rotating as a disc around a central star, just as accretion discs rotate around young stars to form planets. The maser filaments occur at shock boundaries where large regions of gas are colliding.