July 22, 2011

Huge Water Reservoir Found In Space

A team of astronomers have discovered the largest and farthest reservoir of water ever detected in the universe.

The researchers found a mass of water vapor that is at least 140 trillion times that of all water in the world's oceans combined, and 100,000 times more massive than the sun.

The team said the light has taken 12 billion years to reach Earth, and the astronomers were observing the light when the universe was just 1.6 billion years old.

"The environment around this quasar is unique in that it's producing this huge mass of water," Matt Bradford, a scientist at NASA's Jet Propulsion Laboratory (JPL), and a visiting associate at Caltech, said in a statement.

"It's another demonstration that water is pervasive throughout the universe, even at the very earliest times."

Fueled by a Black Hole

The quasar is powered by an enormous black hole that is steadily consuming a surrounding disk of gas and dust.

The astronomers studied a particular quasar that harbors a black hole 20 billion times more massive than the sun and produces as much energy as a thousand trillion suns.

Bradford said that since astronomers expected water vapor to be present even in the early universe, the discovery of water itself is not a surprise.

The researchers said that the water vapor is distributed around the black hole in a gaseous region spanning hundreds of light years, and its presence indicates that the gas is unusually warm and dense by astronomical standards.

The water vapor is just one of many kinds of gas that surround the quasar.  The interaction between the radiation and water vapor reveals properties of the gas and how the quasar influences it.

Bradford's team made their discovery in 2008 by using an instrument called Z-Spect at the Caltech Submillimeter Observatory (CSO).   This instrument measures light in a region of the electromagnetic spectrum called the millimeter band, which lies between the infrared and microwave wavelengths.

The astronomers say that this discovery highlights the benefits of observing in the millimeter and submillimeter wavelengths.

The second group of astronomers used the Plateau de Bure Interferometer in the French Alps to find water.  The team was looking for traces of hydrogen fluoride in the spectrum of the same quasar, but ended up detecting a signal in the quasar's spectrum that indicated the presence of water.

Bradford's team will have their papers published in the Astrophysical Journal Letters.


Image Caption: This artist's concept illustrates a quasar, or feeding black hole, similar to APM 08279+5255, where astronomers discovered huge amounts of water vapor. Gas and dust likely form a torus around the black hole, with clouds of charged gas above and below. X-rays emerge from the center, while dust throughout the torus emits infrared radiation. While this figure shows the quasar's torus approximately edge-on, the torus around APM 08279+5255 is likely positioned face-on from our point of view. Credit: NASA/ESA