Methane, the major constituent of natural gas and a prominent product of biologic decay, has been a found to be even more abundant in distant space than on earth.
Scientists have detected methane in three locations: the Orion. A gas cloud, the gas clouds surrounding a variable star known simply as RX Boo, and carbon star identified as IRC-plus 10216. The methane measurements were made using a radio telescope at the National Radio Astronomy Observatory at Greenbank. WN3., and a newer more precise radio telescope at Kitt Park in Arizona.
"This was the first detection of methane outside our solar system," said Dr. Kenneth Fox of the Goddard Space Flight Center, one of two scientists who made the finding, "Methane" appears to be one of the most abundant molecules in Orion A, perhaps second only to hydrogen."
Fox and Goddard's Dr. Donald E. Jennings said the discovery of methane "provides the missing link for the possible production in the cosmos of amino acids," the building blocks of protein and the foundation of life.
Though methane is not one of the most abundant gases in the earth's atmospehere today, it was one of the major components of the earth's primitive atmosphere two billion to three billion years ago. Methane is still a major constituent in the atmospheres of the outer plantets of Jupiter, Saturn, Nepture and Uranus.
Methane is also basic to all the experiments for forming amino acids in the laboratory," Jennings said. "You must start with methane."
No fewer than 40 distinct molecules, including carbon monoxide and formaidehyde, have been found scattered through interstellar dust clouds, but for years scientists searched in vain for methane. Methane does not "resonate" a strong radio signal into space.
"Methane has a strong infrared signal idue to cosmic ray heating from space," Fox said, "but it's washed out by the methane that's present in the earth's atmosphere."
Using the more precise radio telescope at Kitt Peak, Fox and Jennings found no fewer than six separate signals from methane in the molecular cloud in the Orion nebula. So abundant were the methane signals that Fox and Jennings figure one molecule of methane is present in Orion for each 1,000 atomes of hydrogen found there.
Hydrogen is clearly the most abundant gas in the cosmos: Swarming through interstellar space.
The methane to hydrogen ratio of 1 to 1,000 found in the Orion is about the same that scientists see for both gases at Jupiter, whose atmosphere is almost all hydrogen and methane.
Fox and Jennings made their observations of Orion A last November using the Greenbank telescope and last April at Kitt Peak. The detection of methane involved the measuring what Fox called "extremely faint" raido signals coming to earth 10 million billion miles.