Galaxy drags trail of stars behind it
Collisions with hot gas trigger streaks of stellar births

STAR RIVERS The galaxy ESO 137-001, 200 million light-years away, leaves trails (shown in blue in this false-color Hubble Space Telescope image) of gas and newly born stars as it plows through the Norma Cluster. Bright stars in the foreground sit within our galaxy.
Ming Sun/UAH, Serge Meunier, NASA, ESA
It’s raining stars in the Norma galaxy cluster.
ESO 137-001, a galaxy 200 million light-years away in the constellation Triangulum Australe, drags along filaments of gas and stars as it plows through the cluster. The star streams are 260,000 light-years long — more than twice the length of our galaxy. The streams form when ESO 137 slams into hot gas. Wind from the gas sweeps away debris from the galaxy, like confetti blowing off a parade float. The released gas clouds collapse and ignite new stars.
The Hubble Space Telescope snapped pictures of the star streams, which blaze with the intense ultraviolet radiation of star birth (colored blue).