Andrew Yee[_1_]
July 7th 07, 04:22 PM
Office of News and Public Information
National Academies
Contacts:
Paul Jackson
Michelle Strikowsky
Office of News and Public Information
202-334-2138
FOR IMMEDIATE RELEASE: July 6, 2007
Life Elsewhere in Solar System Could Be Different From Life as We Know It
WASHINGTON -- The search for life elsewhere in the solar system and beyond
should include efforts to detect what scientists sometimes refer to as
"weird" life -- that is, life with an alternative biochemistry to that of
life on Earth -- says a new report from the National Research Council. The
committee that wrote the report found that the fundamental requirements for
life as we generally know it -- a liquid water biosolvent, carbon-based
metabolism, molecular system capable of evolution, and the ability to
exchange energy with the environment -- are not the only ways to support
phenomena recognized as life. "Our investigation made clear that life is
possible in forms different than those on Earth," said committee chair John
Baross, professor of oceanography at the University of Washington, Seattle.
The report emphasizes that "no discovery that we can make in our exploration
of the solar system would have greater impact on our view of our position in
the cosmos, or be more inspiring, than the discovery of an alien life form,
even a primitive one. At the same time, it is clear that nothing would be
more tragic in the American exploration of space than to encounter alien
life without recognizing it."
The tacit assumption that alien life would utilize the same biochemical
architecture as life on Earth does means that scientists have artificially
limited the scope of their thinking as to where extraterrestrial life might
be found, the report says. The assumption that life requires water, for
example, has limited thinking about likely habitats on Mars to those places
where liquid water is thought to be present or have once flowed, such as the
deep subsurface. However, according to the committee, liquids such as
ammonia or formamide could also work as biosolvents -- liquids that dissolve
substances within an organism -- albeit through a different biochemistry.
The recent evidence that liquid water-ammonia mixtures may exist in the
interior of Saturn's moon Titan suggests that increased priority be given to
a follow-on mission to probe Titan, a locale the committee considers the
solar system's most likely home for weird life.
"It is critical to know what to look for in the search for life in the solar
system," said Baross. "The search so far has focused on Earth-like life
because that's all we know, but life that may have originated elsewhere
could be unrecognizable compared with life here. Advances throughout the
last decade in biology and biochemistry show that the basic requirements for
life might not be as concrete as we thought."
Besides the possibility of alternative biosolvents, studies show that
variations on some of the other basic tenets for life also might be able to
support weird life. DNA on Earth works through the pairing of four chemical
compounds called nucleotides, but experiments in synthetic biology have
created structures with six or more nucleotides that can also encode genetic
information and, potentially, support Darwinian evolution. Additionally,
studies in chemistry show that an organism could utilize energy from
alternative sources, such as through a reaction of sodium hydroxide and
hydrochloric acid, meaning that such an organism could have an entirely
non-carbon-based metabolism.
Researchers need to further explore variations of the requirements for life
with particular emphasis on origin-of-life studies, which will help
determine if life can exist without water or in environments where water is
only present under extreme conditions, the report says. Most planets and
moons in this solar system fall into one of these categories. Research
should also focus on how organisms break down key elements, as even
non-carbon-based life would need elements for energy, structure, and
chemical reactions.
The report also stresses that the future search for alien life should not
exclude additional research into terrestrial life. Through examination of
extreme environments, such as deserts and deep under the oceans, studies
have determined that life exists essentially anywhere water and a source of
energy are found together on Earth. Field researchers should therefore seek
out organisms with novel biochemistries and those that exist in areas where
vital resources are scarce to better understand how life on Earth truly
operates, the committee said. This improved understanding will contribute
greatly toward seeking Earth-like life where the conditions necessary for
its existence might be met, as in the case of subsurface Mars.
Space missions will need adjustment to increase the breadth of their search
for life. Planned Mars missions, for example, should include instruments
that detect components of light elements -- especially carbon, hydrogen,
oxygen, phosphorous, and sulfur -- as well as simple organic functional
groups and organic carbon. Recent evidence indicates that another moon of
Saturn, Enceladus, has active water geysers, raising the prospect that
habitable environments may exist there and greatly increasing the priority
of additional studies of this body.
NASA sponsored the report. The National Academy of Sciences, National
Academy of Engineering, Institute of Medicine, and National Research Council
make up the National Academies. They are private, nonprofit institutions
that provide science, technology, and health policy advice under a
congressional charter. The Research Council is the principal operating
agency of the National Academy of Sciences and the National Academy of
Engineering. A committee roster follows.
Copies of "The Limits of Organic Life in Planetary Systems" will be
available from the National Academies Press; tel. 202-334-3313 or
1-800-624-6242 or on the Internet at http://www.nap.edu . The cost of the
report is $27.50 (prepaid) plus shipping charges of $4.50 for the first copy
and $.95 for each additional copy. Reporters may obtain a pre-publication
copy from the Office of News and Public Information (contacts listed above).
Read Full Report:
http://www.nap.edu/catalog/11919.html
NATIONAL RESEARCH COUNCIL
Division on Engineering and Physical Sciences
Space Studies Board
Committee on the Limits of Organic Life in Planetary Systems
John A. Baross (chair)
Professor of Biological Oceanography
University of Washington
Seattle
Steven A. Benner
Distinguished Fellow
Foundation for Applied Molecular Evolution
Gainesville, Fla.
George D. Cody
Geologist and Member of Senior Research Staff
Geophysical Laboratory
Carnegie Institution of Washington
Washington, D.C.
Shelley D. Copley
Professor
Department of Molecular, Cellular, and Developmental Biology
University of Colorado
Boulder
Norman R. Pace
Professor
Department of Molecular, Cellular, and Developmental Biology
University of Colorado
Boulder
James H. Scott
Leader of the Geobiology Group
Department of Earth Sciences
Dartmouth College
Hanover, N.H.
Robert Shapiro
Professor Emeritus and Senior Research Scientist
Department of Chemistry
New York University
New York City
Mitchell L. Sogin
Director
Bay Paul Center for Comparative Molecular Biology and Evolution
Marine Biological Laboratory
Woods Hole, Mass.
Jeffrey L. Stein
Kauffman Fellow
Sofinnova Ventures
San Francisco
Roger Summons
Professor
Department of Earth, Atmospheric, and Planetary Sciences
Massachusetts Institute of Technology
Cambridge
Jack W. Szostak
Alexander Rich Distinguished Investigator
Massachusetts General Hospital, and
Professor of Genetics
Harvard Medical School
Boston
RESEARCH COUNCIL STAFF
David H. Smith
Study Director
Member, National Academy of Sciences
National Academies
Contacts:
Paul Jackson
Michelle Strikowsky
Office of News and Public Information
202-334-2138
FOR IMMEDIATE RELEASE: July 6, 2007
Life Elsewhere in Solar System Could Be Different From Life as We Know It
WASHINGTON -- The search for life elsewhere in the solar system and beyond
should include efforts to detect what scientists sometimes refer to as
"weird" life -- that is, life with an alternative biochemistry to that of
life on Earth -- says a new report from the National Research Council. The
committee that wrote the report found that the fundamental requirements for
life as we generally know it -- a liquid water biosolvent, carbon-based
metabolism, molecular system capable of evolution, and the ability to
exchange energy with the environment -- are not the only ways to support
phenomena recognized as life. "Our investigation made clear that life is
possible in forms different than those on Earth," said committee chair John
Baross, professor of oceanography at the University of Washington, Seattle.
The report emphasizes that "no discovery that we can make in our exploration
of the solar system would have greater impact on our view of our position in
the cosmos, or be more inspiring, than the discovery of an alien life form,
even a primitive one. At the same time, it is clear that nothing would be
more tragic in the American exploration of space than to encounter alien
life without recognizing it."
The tacit assumption that alien life would utilize the same biochemical
architecture as life on Earth does means that scientists have artificially
limited the scope of their thinking as to where extraterrestrial life might
be found, the report says. The assumption that life requires water, for
example, has limited thinking about likely habitats on Mars to those places
where liquid water is thought to be present or have once flowed, such as the
deep subsurface. However, according to the committee, liquids such as
ammonia or formamide could also work as biosolvents -- liquids that dissolve
substances within an organism -- albeit through a different biochemistry.
The recent evidence that liquid water-ammonia mixtures may exist in the
interior of Saturn's moon Titan suggests that increased priority be given to
a follow-on mission to probe Titan, a locale the committee considers the
solar system's most likely home for weird life.
"It is critical to know what to look for in the search for life in the solar
system," said Baross. "The search so far has focused on Earth-like life
because that's all we know, but life that may have originated elsewhere
could be unrecognizable compared with life here. Advances throughout the
last decade in biology and biochemistry show that the basic requirements for
life might not be as concrete as we thought."
Besides the possibility of alternative biosolvents, studies show that
variations on some of the other basic tenets for life also might be able to
support weird life. DNA on Earth works through the pairing of four chemical
compounds called nucleotides, but experiments in synthetic biology have
created structures with six or more nucleotides that can also encode genetic
information and, potentially, support Darwinian evolution. Additionally,
studies in chemistry show that an organism could utilize energy from
alternative sources, such as through a reaction of sodium hydroxide and
hydrochloric acid, meaning that such an organism could have an entirely
non-carbon-based metabolism.
Researchers need to further explore variations of the requirements for life
with particular emphasis on origin-of-life studies, which will help
determine if life can exist without water or in environments where water is
only present under extreme conditions, the report says. Most planets and
moons in this solar system fall into one of these categories. Research
should also focus on how organisms break down key elements, as even
non-carbon-based life would need elements for energy, structure, and
chemical reactions.
The report also stresses that the future search for alien life should not
exclude additional research into terrestrial life. Through examination of
extreme environments, such as deserts and deep under the oceans, studies
have determined that life exists essentially anywhere water and a source of
energy are found together on Earth. Field researchers should therefore seek
out organisms with novel biochemistries and those that exist in areas where
vital resources are scarce to better understand how life on Earth truly
operates, the committee said. This improved understanding will contribute
greatly toward seeking Earth-like life where the conditions necessary for
its existence might be met, as in the case of subsurface Mars.
Space missions will need adjustment to increase the breadth of their search
for life. Planned Mars missions, for example, should include instruments
that detect components of light elements -- especially carbon, hydrogen,
oxygen, phosphorous, and sulfur -- as well as simple organic functional
groups and organic carbon. Recent evidence indicates that another moon of
Saturn, Enceladus, has active water geysers, raising the prospect that
habitable environments may exist there and greatly increasing the priority
of additional studies of this body.
NASA sponsored the report. The National Academy of Sciences, National
Academy of Engineering, Institute of Medicine, and National Research Council
make up the National Academies. They are private, nonprofit institutions
that provide science, technology, and health policy advice under a
congressional charter. The Research Council is the principal operating
agency of the National Academy of Sciences and the National Academy of
Engineering. A committee roster follows.
Copies of "The Limits of Organic Life in Planetary Systems" will be
available from the National Academies Press; tel. 202-334-3313 or
1-800-624-6242 or on the Internet at http://www.nap.edu . The cost of the
report is $27.50 (prepaid) plus shipping charges of $4.50 for the first copy
and $.95 for each additional copy. Reporters may obtain a pre-publication
copy from the Office of News and Public Information (contacts listed above).
Read Full Report:
http://www.nap.edu/catalog/11919.html
NATIONAL RESEARCH COUNCIL
Division on Engineering and Physical Sciences
Space Studies Board
Committee on the Limits of Organic Life in Planetary Systems
John A. Baross (chair)
Professor of Biological Oceanography
University of Washington
Seattle
Steven A. Benner
Distinguished Fellow
Foundation for Applied Molecular Evolution
Gainesville, Fla.
George D. Cody
Geologist and Member of Senior Research Staff
Geophysical Laboratory
Carnegie Institution of Washington
Washington, D.C.
Shelley D. Copley
Professor
Department of Molecular, Cellular, and Developmental Biology
University of Colorado
Boulder
Norman R. Pace
Professor
Department of Molecular, Cellular, and Developmental Biology
University of Colorado
Boulder
James H. Scott
Leader of the Geobiology Group
Department of Earth Sciences
Dartmouth College
Hanover, N.H.
Robert Shapiro
Professor Emeritus and Senior Research Scientist
Department of Chemistry
New York University
New York City
Mitchell L. Sogin
Director
Bay Paul Center for Comparative Molecular Biology and Evolution
Marine Biological Laboratory
Woods Hole, Mass.
Jeffrey L. Stein
Kauffman Fellow
Sofinnova Ventures
San Francisco
Roger Summons
Professor
Department of Earth, Atmospheric, and Planetary Sciences
Massachusetts Institute of Technology
Cambridge
Jack W. Szostak
Alexander Rich Distinguished Investigator
Massachusetts General Hospital, and
Professor of Genetics
Harvard Medical School
Boston
RESEARCH COUNCIL STAFF
David H. Smith
Study Director
Member, National Academy of Sciences