How do Gas and Stars Build a Galaxy?
ALMA image of Sculptor (NGC 253), a ‘starburst’ galaxy with a diffuse envelope of carbon monoxide gas (in red) which surrounds star-forming regions (in yellow). The ALMA data are superimposed on a Hubble image that covers part of the same region. Credit: B. Saxton (NRAO/AUI/NSF); ALMA (NRAO/ESO/NAOJ); A. Leroy; STScI/NASA, ST-ECF/ESA, CADC/NRC/CSA
When we look up at the night sky outside of the bright city, we can see a dazzling array of stars and galaxies. It is more difficult to see the clouds of gas within galaxies, however, but gas is required to form new stars and allow galaxies to grow. Although gas makes up less than 1% of the matter in the universe, “it’s the gas that drives the evolution of the galaxy, not the other way around,” says Felix “Jay” Lockman of the National Radio Astronomy Observatory (NRAO).
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