"Long before it's in the papers"
August 02, 2011

RETURN TO THE WORLD SCIENCE HOME PAGE

Oxygen molecules “confirmed” in space

Aug. 2, 2011
Courtesy of NASA
and World Science staff

As­tro­no­mers say they have con­firmed for the first time that there are ox­y­gen mol­e­cules in out­er space. But how they got there is not so cer­tain.

In­di­vid­ual ox­y­gen atoms are com­mon in space, but it has prov­en far harder to find ox­y­gen in mo­lec­u­lar form, as it ex­ists in the air we breathe. Mo­lec­u­lar ox­y­gen con­sists of two ox­y­gen atoms joined to­geth­er and makes up about 20 per­cent of the air. 

“Oxy­gen gas was dis­cov­ered in the 1770s, but it’s tak­en us more than 230 years to fi­nally say with cer­tain­ty that this very sim­ple mol­e­cule ex­ists in space,” said Paul Gold­smith, NASA’s Her­schel proj­ect sci­ent­ist at the agen­cy’s Je­t Pro­pul­sion Lab­o­r­a­to­ry in Pas­a­de­na, Ca­lif. Gold­smith is lead au­thor of a re­cent pa­per de­scrib­ing the find­ings in The As­t­ro­phys­i­cal Jour­nal.

The find­ing was made us­ing the Her­schel Space Observato­ry, a Eu­ro­pe­an Space Agency-led mis­sion with NASA con­tri­bu­tions.

As­tro­no­mers searched for the elu­sive mol­e­cules in space for dec­ades us­ing bal­loons, as well as ground- and space-based tele­scopes. The Swed­ish Odin tel­e­scope spot­ted the mol­e­cule in 2007, but the sight­ing could not be con­firmed.

Gold­smith and his col­leagues pro­pose that ox­y­gen is locked up in wa­ter ice that coats ti­ny dust grains. They think the ox­y­gen de­tected by Her­schel in an ar­ea called the Ori­on Neb­u­la—in the di­rec­tion of the con­stella­t­ion Ori­on—was formed af­ter star­light warmed the icy grains. Part of this re­leased wa­ter was con­vert­ed in­to ox­y­gen mol­e­cules.

“This ex­plains where some of the ox­y­gen might be hid­ing,” said Gold­smith. “But we did­n’t find large amounts of it, and still don’t un­der­stand what is so spe­cial about the spots where we find it. The uni­verse still holds many se­crets.” The re­search­ers plan to con­tin­ue their hunt for ox­y­gen mol­e­cules in oth­er star-forming re­gions.

“Oxy­gen is the third most com­mon el­e­ment in the uni­verse and its mo­lec­u­lar form must be abun­dant in space,” said Bill Danchi, Her­schel pro­gram sci­ent­ist at NASA Head­quar­ters in Wash­ing­ton. “Her­schel is prov­ing a pow­er­ful tool to probe this un­solved mys­tery.”

* * *

Astronomers say they have confirmed for the first time that there are oxygen molecules in outer space. Individual oxygen atoms are common in space, but it has proven far harder to find oxygen in molecular form, as it exists in the air we breathe. Molecular oxygen consists of two oxygen atoms joined together and makes up about 20 percent of the air. “Oxygen gas was discovered in the 1770s, but it’s taken us more than 230 years to finally say with certainty that this very simple molecule exists in space,” said Paul Goldsmith, NASA’s Herschel project scientist at the agency’s Jet Propulsion Laboratory in Pasadena, Calif. Goldsmith is lead author of a recent paper describing the findings in the Astrophysical Journal. The finding was made using the Herschel Space Observatory, a European Space Agency-led mission with NASA contributions. Astronomers searched for the elusive molecules in space for decades using balloons, as well as ground- and space-based telescopes. The Swedish Odin telescope spotted the molecule in 2007, but the sighting could not be confirmed. Goldsmith and his colleagues propose that oxygen is locked up in water ice that coats tiny dust grains. They think the oxygen detected by Herschel in an area called the Orion Nebula—in the direction of the constellation Orion—was formed after starlight warmed the icy grains. This released water, which was converted into oxygen molecules. “This explains where some of the oxygen might be hiding,” said Goldsmith. “But we didn’t find large amounts of it, and still don’t understand what is so special about the spots where we find it. The universe still holds many secrets.” The researchers plan to continue their hunt for oxygen molecules in other star-forming regions. “Oxygen is the third most common element in the universe and its molecular form must be abundant in space,” said Bill Danchi, Herschel program scientist at NASA Headquarters in Washington. “Herschel is proving a powerful tool to probe this unsolved mystery.”