Biggest cloud of water in universe discovered

Posted by Kate Taylor

Astronomers have found an enormous cloud of water - containing 140 trillion times as much as is found on Earth - floating around a distant quasar.

It's also the most distant and therefore oldest body of water ever found, they say, with the observations revealing it as it was 12 billion years ago, just 1.6 billion years after the Big Bang.

The quasar around which the cloud floats is one of the most powerful known objects in the universe and has an energy output of 1,000 trillion suns. Its power comes from matter spiraling into the central supermassive black hole, around 20 billion times the mass of our sun.

The amount of water estimated to be in the quasar is at least 100,000 times the mass of the sun, equivalent to 34 billion times the mass of the Earth.

"These findings are very exciting," says CU-Boulder associate professor Jason Glenn. "We not only detected water in the farthest reaches of the universe, but enough to fill Earth's oceans more than 100 trillion times."

Measurements indicate that there's enough gas present for the black hole to grow to about six times its already massive size - although some of the gas may end up forming stars instead, or be ejected from the quasar host galaxy in an outflow.

In the Milky Way, there's at least 4,000 times less gaseous water than in the quasar, partly because most of the water in our own galaxy is frozen into ice. And while water vapor in the Milky Way is found only in certain regions, a few light years across at most, the water in the distant quasar appears to be spread over hundreds of light years.

The discovery was made with a spectrograph called Z-Spec operating in the millimeter wavelengths at the Caltech Submillimeter Observatory in Hawaii.

"Breakthroughs are coming fast in millimeter and submillimeter technology, enabling us to study ancient galaxies caught in the act of forming stars and supermassive black holes," says Glenn.