Andrew Yee[_1_]
June 4th 08, 05:19 AM
National Radio Astronomy Observatory
P.O. Box O
Socorro, NM 87801
http://www.nrao.edu
Contact:
Dave Finley, Public Information Officer
(505) 835-7302
EMBARGOED For Release: 9:20 a.m., CDT, Monday, June 2, 2008
Mining for Molecules in the Milky Way
Scientists are using the giant Robert C. Byrd Green Bank Telescope (GBT) to
go prospecting in a rich molecular cloud in our Milky Way Galaxy. They seek
to discover new, complex molecules in interstellar space that may be
precursors to life.
"Clouds like this one are the raw material for new stars and planets. We
know that complex chemistry builds prebiotic molecules in such clouds long
before the stars and planets are formed. There is a good chance that some of
these interstellar molecules may find their way to the surface of young
planets such as the early Earth, and provide a head start for the chemistry
of life. For the first time, we now have the capability to make a very
thorough and methodical search to find all the chemicals in the clouds,"
said Anthony Remijan, of the National Radio Astronomy Observatory (NRAO).
In the past three years, Remijan and his colleagues have used the GBT to
discover ten new interstellar molecules, a feat unequalled in such a short
time by any other team or telescope.
The scientists discovered those molecules by looking specifically for them.
However, they now are changing their strategy and casting a wide net
designed to find whatever molecules are present, without knowing in advance
what they'll find. In addition, they are making their data available freely
to other scientists, in hopes of speeding the discovery process. The
research team presented its plan to the American Astronomical Society's
meeting in St. Louis, MO.
As molecules rotate and vibrate, they emit radio waves at specific
frequencies. Each molecule has a unique pattern of such frequencies, called
spectral lines, that constitutes a "fingerprint" identifying that molecule.
Laboratory tests can determine the pattern of spectral lines that identifies
a specific molecule.
Most past discoveries came from identifying a molecule's pattern in the
laboratory, then searching with a radio telescope for that set of spectral
lines in a region of sky. So far, more than 140 different molecules have
been found that way in interstellar space.
The new study reverses the process. The astronomers will use the GBT to
study a cloud of gas and dust in detail, finding all the spectral lines
first, then later trying to match them up to molecular patterns using
data-mining software.
The astronomers will make a thorough survey of the interstellar cloud in the
wide range of radio frequencies between 300 MHz to 50 GHz. This technique,
they said, will allow them to discover molecules that would elude more
narrow-range observations.
"This strategy wasn't possible at frequencies between 300 MHz and 50 GHz
before the GBT. That telescope's tremendous capabilities enable us to open a
whole new era of astrochemistry," said Jan M. Hollis, of NASA's Goddard
Space Flight Center.
"Based on earlier studies, there are a number of complex, prebiotic
molecules that we think are present in such clouds, but only this wide-net
approach with the GBT will capture the evidence we need to discover them,"
Remijan said.
"Complex organic molecules formed in interstellar space are undoubtedly the
fundamental building blocks of astrobiology. The complete inventory of such
molecules in this cloud will produce a tremendous advance in our
understanding of the physical conditions in that cloud and of the first
chemical steps toward life," said Phil Jewell, of the NRAO.
As the survey with the GBT continues, the research team plans to release
their data to the scientific community. In addition, they are providing
software that will allow other scientists to efficiently "mine" the data for
the telltale evidence of new molecules.
"There is a wealth of laboratory data now available about the radio
fingerprints of many molecules. Data-mining software will make it possible
to efficiently match up the spectral lines seen in the laboratory with ones
we observe in the interstellar clouds," said Frank Lovas of the National
Institute for Standards and Technology.
The scientists are observing Sagittarius B2(N), a cloud near the center of
our Galaxy, some 25,000 light-years from Earth, Numerous molecules have been
discovered in that cloud in the past.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation, operated under cooperative agreement by Associated
Universities, Inc.
IMAGE CAPTION:
[http://www.nrao.edu/pr/2008/molmine/GBT_Molecules.jpg (57KB)]
The Robert C. Byrd Green Bank Telescope and some molecules it has
discovered. CREDIT: Bill Saxton, NRAO/AUI/NSF
P.O. Box O
Socorro, NM 87801
http://www.nrao.edu
Contact:
Dave Finley, Public Information Officer
(505) 835-7302
EMBARGOED For Release: 9:20 a.m., CDT, Monday, June 2, 2008
Mining for Molecules in the Milky Way
Scientists are using the giant Robert C. Byrd Green Bank Telescope (GBT) to
go prospecting in a rich molecular cloud in our Milky Way Galaxy. They seek
to discover new, complex molecules in interstellar space that may be
precursors to life.
"Clouds like this one are the raw material for new stars and planets. We
know that complex chemistry builds prebiotic molecules in such clouds long
before the stars and planets are formed. There is a good chance that some of
these interstellar molecules may find their way to the surface of young
planets such as the early Earth, and provide a head start for the chemistry
of life. For the first time, we now have the capability to make a very
thorough and methodical search to find all the chemicals in the clouds,"
said Anthony Remijan, of the National Radio Astronomy Observatory (NRAO).
In the past three years, Remijan and his colleagues have used the GBT to
discover ten new interstellar molecules, a feat unequalled in such a short
time by any other team or telescope.
The scientists discovered those molecules by looking specifically for them.
However, they now are changing their strategy and casting a wide net
designed to find whatever molecules are present, without knowing in advance
what they'll find. In addition, they are making their data available freely
to other scientists, in hopes of speeding the discovery process. The
research team presented its plan to the American Astronomical Society's
meeting in St. Louis, MO.
As molecules rotate and vibrate, they emit radio waves at specific
frequencies. Each molecule has a unique pattern of such frequencies, called
spectral lines, that constitutes a "fingerprint" identifying that molecule.
Laboratory tests can determine the pattern of spectral lines that identifies
a specific molecule.
Most past discoveries came from identifying a molecule's pattern in the
laboratory, then searching with a radio telescope for that set of spectral
lines in a region of sky. So far, more than 140 different molecules have
been found that way in interstellar space.
The new study reverses the process. The astronomers will use the GBT to
study a cloud of gas and dust in detail, finding all the spectral lines
first, then later trying to match them up to molecular patterns using
data-mining software.
The astronomers will make a thorough survey of the interstellar cloud in the
wide range of radio frequencies between 300 MHz to 50 GHz. This technique,
they said, will allow them to discover molecules that would elude more
narrow-range observations.
"This strategy wasn't possible at frequencies between 300 MHz and 50 GHz
before the GBT. That telescope's tremendous capabilities enable us to open a
whole new era of astrochemistry," said Jan M. Hollis, of NASA's Goddard
Space Flight Center.
"Based on earlier studies, there are a number of complex, prebiotic
molecules that we think are present in such clouds, but only this wide-net
approach with the GBT will capture the evidence we need to discover them,"
Remijan said.
"Complex organic molecules formed in interstellar space are undoubtedly the
fundamental building blocks of astrobiology. The complete inventory of such
molecules in this cloud will produce a tremendous advance in our
understanding of the physical conditions in that cloud and of the first
chemical steps toward life," said Phil Jewell, of the NRAO.
As the survey with the GBT continues, the research team plans to release
their data to the scientific community. In addition, they are providing
software that will allow other scientists to efficiently "mine" the data for
the telltale evidence of new molecules.
"There is a wealth of laboratory data now available about the radio
fingerprints of many molecules. Data-mining software will make it possible
to efficiently match up the spectral lines seen in the laboratory with ones
we observe in the interstellar clouds," said Frank Lovas of the National
Institute for Standards and Technology.
The scientists are observing Sagittarius B2(N), a cloud near the center of
our Galaxy, some 25,000 light-years from Earth, Numerous molecules have been
discovered in that cloud in the past.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation, operated under cooperative agreement by Associated
Universities, Inc.
IMAGE CAPTION:
[http://www.nrao.edu/pr/2008/molmine/GBT_Molecules.jpg (57KB)]
The Robert C. Byrd Green Bank Telescope and some molecules it has
discovered. CREDIT: Bill Saxton, NRAO/AUI/NSF