Universe's Largest Reservoir Of Water Orbiting Distant Quasar
Scientists at Caltech have announced the discovery of the largest concentration of water in the known universe. Surrounding the quasar APM 08279+5255, the cloud of water vapor is calculated to contain more than 140 trillion times the amount of water in all of Earth's oceans.
The quasar, which envelops a black hole 20 billion times more massive than our sun, has been observed at a distance of 12 billion light-years, or approximately 705 thousand million billion miles. This incredible distance means the light from the quasar and its orbiting vapor cloud has taken 12 billion years to reach recording devices here on Earth; put it another way, when scientists observe this system, they are looking into the universe's ancient past—when it was hardly 1.6 billion years old. The universe's age is currently estimated at 13.75 billion years.
The discovery of this huge mass of water is particularly surprising because scientists previously believed water was not present until much later. In fact, this finding has prompted scientists to change their understanding of the complex physical and chemical processes that shaped the evolution of the universe following its fiery birth in the Big Bang.
"To me, the most exciting aspect of this discovery is that it demonstrates how pervasive water is even at a tenth the current age of the universe," said Eric Murphy, a Carnegie Observatories astronomer who co-authored the study, in an interview with National Geographic.
The fact that the water is orbiting a quasar makes the find more surprising still. A quasar, abbreviated for quasi-stellar radio source, is a pointlike object in deep space with unusually high “redshift"--a method by which scientists measure how quickly an object is moving away from Earth.
Scientists have debated the precise nature of quasars until the 1980s, when increasingly accurate measurements revealed them to be black holes. These black holes were usually at the centers of large galaxies, pulling large amounts of matter into circular orbits known as accretion discs. What distinguishes them from traditional black holes, however, is the massive amount of energy released--usually in the form of x-rays, infrared, and visible light, when matter from the accretion disc crosses the black hole's event horizon and is absorbed. This energy is what “powers” the quasar and gives it the high redshift scientists observe.
The energy from APM 08279+5255 is also heating the surrounding gas and dust to a temperature of -53 degrees Celcius (-63 Fahrenheit). While still cold by normal standards, this is five times hotter than what is typical inside galaxies like the Milky Way—a highly unusual discovery in itself. This phenomenon may help scientists understand water's role as a possible “coolant” in the early universe, absorbing energy emitted when galaxies and stars form. It may also shed light on the precise methods by which our own Sun and planetary system formed approximately 4.6 billion years ago.
This new finding will be published by the Caltech team in The Astrophysical Journal Letters, a peer-reviewed astrophysical journal that allows publication of significant finds on short notice.
Reach Staff Writer Sean McGuire here.