Discovery in the Atacama

Astronomers in Chile discover first evidence of dark galaxies

Dark galaxies, thought to be the building blocks of today’s star-filled galaxies, may have been spotted for the first time by researchers in Chile. 

Monday, August 20, 2012 Category: Education
An international team believes they have captured the first images of dark galaxies, or gas-rich gal An international team believes they have captured the first images of dark galaxies, or gas-rich galaxies with no stars. Photo courtesy of ESO Astronomy / Facebook.

The Very Large Telescope (VLT) at Chile’s Cerro Paranal observatory - currently the largest optical telescope in the world - has captured evidence of dark galaxies for the first time.


A precursor to galaxy formation, these dark galaxies had been previously predicted by theory but remained, until now, unobserved.


“Dark galaxies are small, gas-rich galaxies in the early universe that are very inefficient at forming stars,” wrote the European Southern Observatory (ESO) in a statement about the findings. ESO is the intergovernmental research organisation that hosts the VLT.


“They [dark galaxies] are predicted by theories of galaxy formation and are thought to be the building blocks of today’s bright, star-filled galaxies,” the ESO wrote.  “Astronomers think that they may have fed large galaxies with much of the gas that later formed into the stars that exist today.”


Since they are essentially devoid of stars and don't emit much light, dark galaxies are very hard to detect. The international team thinks they have documented dark galaxy presence by observing them glowing as they are illuminated by a quasar - a very energetic and luminous active galactic nucleus.


"The light from the quasar makes the dark galaxies light up in a process similar to how white clothes are illuminated by ultraviolet lamps in a night club," co-author of the findings Simon Lilly told UC Santa Cruz Review.


Dark galaxies are not the only ground-breaking discovery found by the VLT this year. In January, the VLT captured the largest known galaxy cluster, and in February it documented the most precise image yet seen of the birth of the Carina Nebula.

Discoveries like these have made Chile the world’s premiere site for astronomy, with the incredibly clear skies and altitude of Chile’s Atacama Desert providing an unparalleled platform for viewing objects that exist thousands of light years from Earth. 

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