Although it seems counterintuitive, it is not possible to conclude from the pervasive presence of the basic building blocks of life -organics and water- in our solar system and beyond, that life itself might be commonplace. But, using common sense, while recognizing that it is a long road from simple building blocks to complex organisms, life could have formed almost anywhere in the cosmos.
University of Arizona radio observatory team probing the oxygen-rich environment around a supergiant star, VY Canis Majoris, with one of the world's most sensitive radio telescopes have discovered a score of molecules that include compounds needed for life.
"I don't think anyone would have predicted that VY Canis Majoris is a molecular factory. It was really unexpected," said Arizona Radio Observatory (ARO) Director Lucy Ziurys, UA professor of astronomy and of chemistry. "Everyone thought that the interesting chemistry in gas clouds around old stars was happening in envelopes around nearer, carbon-rich stars," Ziurys said. "But when we started looking closely for the first time at an oxygen-rich object, we began finding all these interesting things that weren't supposed to be there."
VY Canis Majoris, one of the most luminous infrared objects in the sky, is an old star about 5,000 light years away. It's a half million times more luminous than the sun, but glows mostly in the infrared because it's a cool star. It truly is "supergiant" -- 25 times as massive as the sun and so huge that it would fill the orbit of Jupiter. But the star is losing mass so fast that in a million years -- an astronomical eyeblink -- it will be gone.
The star already has blown away a large part of its atmosphere,
creating its surrounding envelope that contains about twice as much
oxygen as carbon.
Among the molecules Ziurys and her team reported in Nature are table salt (NaCl); a compound called phosphorus nitride (PN), which contains two of the five most necessary ingredients for life; molecules of HNC, which is a variant form of the organic molecule, hydrogen cyanide; and an ion molecule form of carbon monoxide that comes with a proton attached (HCO+). Astronomers have found very little phosphorus or ion molecule chemistry in outflows from cool stars until now.
"We think these molecules eventually flow from the star into the interstellar medium, which is the diffuse gas between stars. The diffuse gas eventually collapses into denser molecular clouds, and from these solar systems eventually form," Ziurys said.
Comets and meteorites dump about 40,000 tons of interstellar dust on Earth each year. We wouldn't be carbon-based life forms otherwise, Ziurys noted, because early Earth lost all of its original carbon in the form of a methane atmosphere.
"The origin of organic material on Earth -- the chemical compounds that make up you and me -- probably came from interstellar space. So one can say that life's origins really begin in chemistry around objects like VY Canis Majoris."
Until recently, astronomers did not believe molecules could survive the harsh environment of space. Ultraviolet radiation supposedly reduced matter to atoms and atomic ions. They now conclude that at least half of the gas in space between the stars within the 33-light-year inner galaxy is molecular, Ziurys said. "Our results are more evidence that we live in a really molecular universe, as opposed to an atomic one," Ziurys said.
The U of Arizona's team discovery seems yet another chip put in place that will form part of the eventual confirmation of the view of cosmos as a bio-friendly construct -the Goldilocks Factor - a universe that seems "just right for life."
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