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Star struck! The International Year of Astronomy
POSTED 8 JANUARY 2009

Long-distance beverage?

A view of the white dish's front.  It's surrounded by trees, which appear small by comparison
The 100-meter radio telescope at Effelsberg, Germany, detected the most distant water in the universe.

Thirsty? Can we suggest an antique vintage of water with a "bottled-on" date of 11.1 billion years BC? This beatified beverage was just discovered in a quasar -- a gargantuo galaxy that was spewing a titanic stream of microwaves roughly 3 billion years after the Big Bang.

Although water is essential to every known type of life, nobody is claiming that little green creatures were bottling ancient eau d'Galaxie....

And before you take a sip, remember that the 450° Celsius conditions around the source of the microwaves means the H2O was vapor, not liquid.

We pause to explain. In a new study (see #1 in the bibliography), astronomer Violette Impellizzeri and her colleagues detected a water signal in a maser, a laserlike beam of microwaves that began its journey in a black hole at the center of the galaxy MG J0414+0534 about 11.1 billion years ago.

The discovery came from an analysis of the maser, which showed intense bands of radiation in a wavelength that signified water. The beam of microwaves was apparently shot from the accretion disk of a super-massive black hole, which may have had the mass in the range of 1 million suns.

Impellizzeri, who is now at the U.S. National Radio Astronomy Observatory, did this study while a graduate student at the Max Planck Institute for Radioastronomy in Germany.

A rainbow-banded, warped spiral disc with two blue jets emitted vertically from its luminous center.
Image: NASA
A super-massive black hole attracts the orbiting material in its accretion disk and creates a maser -- a microwave laser. A water maser can produce the tell-tale, triple-peaked spectral fingerprint seen at center.

Getting bent

The observation of MG J0414+0534 benefited from a giant lens that focused the microwaves and reduced the observing time to 14 hours. (Had nature neglected to place this lens in the path of the maser, the observation could have required 580 days.) The big lens is not glass, but rather a "cosmic telescope" or a "gravitational lens" built to the specifications of Albert Einstein, who deduced that a fantastically strong gravitational field can bend electromagnetic radiation.

A simple diagram shows a galaxy between earth and a quasar.  Two images of the quasar are produced.
Image: NASA
A gravity lens created by a massive galaxy bends light from a distant object, focusing the radiation and producing multiple images.

"The signal we detected is really faint, and it would not have been detected in such short time were it not for the galaxy in between us," says Impellizzeri, who did not bother specifying the obvious: it's near-impossible for anyone -- let alone a graduate student -- to monopolize a telescope for more than 18 months.

Because the universe has been expanding ever since the microwave beam began its journey, the black hole that set the microwaves in motion, if it still exists, would be roughly 20 billion light years distant.

Bang!

The discovery of water tells us something about a remote, ill-understood period just 3 billion years after the Big Bang started the universe and released several bucketsful of intensely energetic elementary particles. It's unclear how long it was until atoms -- let alone molecules -- appeared, but the study reinforces the idea that "molecules had formed really early on in the universe," Impellizzeri says. "It was expected that water should already be there, but it had not been observed [at such distance] before."

Galaxies are in pink against a purple background.  The graph shows a spike at 6.17 gigahertz
Top left: The spectrum shows water in yellow. Center: Four images of the source galaxy resulted from gravitational distortion caused by the foreground galaxy. Bottom right: Nearby galaxy M87 is a modern-day counterpart of the ancient galaxy that shot microwaves toward us.

Curiously, intense masers were apparently as common as fleas on a hound dog in the young universe, since the first object that the research team chose to study turned out to have one. Subsequent observations have revealed several more, says Impellizzeri.

Modern galaxies, in contrast, are short-stocked for beefy masers. "The probability of finding an astonishingly bright one in the first object was very surprising," says Impellizzeri. "They are found in one-fifth of the local galaxies around us," but the odds of finding such a bright one around here are closer to a million to one.

Which may be just as well, since a big maser could cook this lovely planet like a stale bagel in a blast furnace. It sure would singe the paint on that '63 Ford Galaxie...

As would an ice volcano...
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Terry Devitt, editor; Nathan Hebert, project assistant; S.V. Medaris, designer/illustrator; David Tenenbaum, feature writer; Amy Toburen, content development executive

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