Hiding from Jupiter's Radiation

January 19, 2009 / Written by: Michael Schirber

Researchers as part of NASA’s Exobiology and Evolutionary Biology program are mapping the surfaces of Jupiter’s moons Europa and Ganymede. One goal is to identify ‘dead zones’ where the powerful radiation of Jupiter would likely destroy any interesting organic compounds. The team also hopes to find areas that are possible ‘safe havens’ – where materials expelled from the moons’ subsurface oceans might survive. Such areas could be extremely important sites for future missions to the Jovian system.

Source: [Astrobiology Magazine]

Replicating RNA

January 16, 2009 / Posted by: Aaron Gronstal

Researchers at the Scripps Research Institute have made important steps toward understanding how life originated by shedding light on the ‘RNA World’ hypothesis. The ‘RNA World’ refers to the idea that life on Earth went through a stage where RNA was used to store information and act as a catalyst, much like DNA and proteins are used in organisms today. A critical component of this stage would be that RNA molecules would have to replicate themselves. The team at Scripps has now synthesized RNA enzymes that can replicate themselves without the help of additional molecules. These RNA-based, self-replicating systems could be a model for how life on Earth first began to operate.

Source: [Astrobiology Magazine]

Martian Methane Reveals the Red Planet is not a Dead Planet

January 15, 2009 / Posted by: Marco Boldt

Mars today is a world of cold and lonely deserts, apparently without life of any kind, at least on the surface. Worse still, it looks like Mars has been cold and dry for billions of years, with an atmosphere so thin, any liquid water on the surface quickly boils away while the sun’s ultraviolet radiation scorches the ground.

But there is evidence of a warmer and wetter past — features resembling dry riverbeds and minerals that form in the presence of water indicate water once flowed through Martian sands. Since liquid water is required for all known forms of life, scientists wonder if life could have risen on Mars, and if it did, what became of it as the Martian climate changed.

New research reveals there is hope for Mars yet. The first definitive detection of methane in the atmosphere of Mars indicates the planet is still alive, in either a biologic or geologic sense, according to a team of NASA and university scientists.

“Methane is quickly destroyed in the Martian atmosphere in a variety of ways, so our discovery of substantial plumes of methane in the northern hemisphere of Mars in 2003 indicates some ongoing process is releasing the gas,” said Dr. Michael Mumma of NASA’s Goddard Space Flight Center in Greenbelt, Md. “At northern mid-summer, methane is released at a rate comparable to that of the massive hydrocarbon seep at Coal Oil Point in Santa Barbara, Calif.”

Methane — four atoms of hydrogen bound to a carbon atom — is the main component of natural gas on Earth. It’s of interest to astrobiologists because organisms release much of Earth’s methane as they digest nutrients. However, other purely geological processes, like oxidation of iron, also release methane. “Right now, we don’t have enough information to tell if biology or geology — or both — is producing the methane on Mars,” said Mumma. “But it does tell us that the planet is still alive, at least in a geologic sense. It’s as if Mars is challenging us, saying, hey, find out what this means.” Mumma is lead author of a paper on this research appearing in Science Express Jan. 15.

If microscopic Martian life is producing the methane, it likely resides far below the surface, where it’s still warm enough for liquid water to exist. Liquid water, as well as energy sources and a supply of carbon, are necessary for all known forms of life.

“On Earth, microorganisms thrive 2 to 3 kilometers (about 1.2 to 1.9 miles) beneath the Witwatersrand basin of South Africa, where natural radioactivity splits water molecules into molecular hydrogen (H2) and oxygen. The organisms use the hydrogen for energy. It might be possible for similar organisms to survive for billions of years below the permafrost layer on Mars, where water is liquid, radiation supplies energy, and carbon dioxide provides carbon,” said Mumma.

“Gases, like methane, accumulated in such underground zones might be released into the atmosphere if pores or fissures open during the warm seasons, connecting the deep zones to the atmosphere at crater walls or canyons,” said Mumma.

“Microbes that produced methane from hydrogen and carbon dioxide were one of the earliest forms of life on Earth,” noted Dr. Carl Pilcher, Director of the NASA Astrobiology Institute which partially supported the research. “If life ever existed on Mars, it’s reasonable to think that its metabolism might have involved making methane from Martian atmospheric carbon dioxide.”

However, it is possible a geologic process produced the Martian methane, either now or eons ago. On Earth, the conversion of iron oxide (rust) into the serpentine group of minerals creates methane, and on Mars this process could proceed using water, carbon dioxide, and the planet’s internal heat. Although we don’t have evidence on Mars of active volcanoes today, ancient methane trapped in ice “cages” called clathrates might now be released.

The team found methane in the atmosphere of Mars by carefully observing the planet over several Mars years (and all Martian seasons) with NASA’s Infrared Telescope Facility, run by the University of Hawaii, and the W. M. Keck telescope, both at Mauna Kea, Hawaii.

The team used spectrometer instruments attached to the telescopes to make the detection. Spectrometers spread light into its component colors, like a prism separates white light into a rainbow. The team looked for dark areas in specific places along the rainbow (light spectrum) where methane was absorbing sunlight reflected from the Martian surface. They found three such areas, called absorption lines, which together are a definitive signature of methane, according to the team. They were able to distinguish lines from Martian methane from the methane in Earth’s atmosphere because the motion of the Red Planet shifted the position of the Martian lines, much as a speeding ambulance causes its siren to change pitch as it passes by.

“We observed and mapped multiple plumes of methane on Mars, one of which released about 19,000 metric tons of methane,” said Dr. Geronimo Villanueva of the Catholic University of America, Washington, D.C. Villanueva is stationed at NASA Goddard and is co-author of the paper. “The plumes were emitted during the warmer seasons — spring and summer — perhaps because the permafrost blocking cracks and fissures vaporized, allowing methane to seep into the Martian air. Curiously, some plumes had water vapor while others did not,” said Villanueva.

According to the team, the plumes were seen over areas that show evidence of ancient ground ice or flowing water. For example, plumes appeared over northern hemisphere regions such as east of Arabia Terra, the Nili Fossae region, and the south-east quadrant of Syrtis Major, an ancient volcano 1,200 kilometers (about 745 miles) across.

It will take future missions, like NASA’s Mars Science Laboratory, to discover the origin of the Martian methane. One way to tell if life is the source of the gas is by measuring isotope ratios. Isotopes are heavier versions of an element; for example, deuterium is a heavier version of hydrogen. In molecules that contain hydrogen, like water and methane, the rare deuterium occasionally replaces a hydrogen atom. Since life prefers to use the lighter isotopes, if the methane has less deuterium than the water released with it on Mars, it’s a sign that life is producing the methane. The research was funded by NASA’s Planetary Astronomy Program and the NASA Astrobiology Institute.

Source: [NASA]

Methane-Spewing Martians?

January 15, 2009 / Written by: Michael Schirber

A research team, funded as part of the Astrobiology Science and Technology Instrument Development and Mission Concept Studies (ASTID), is building optical devices that may help scientists understand if methane on Mars could be a sign of life. The recent discovery of methane in the atmosphere of Mars raised the question of whether or not the gas could be produced by living organisms. The team hopes their instruments will be able to measure isotopic abundances in methane signatures that could distinguish a biological origin from a geological one.

Source: [Astrobiology Magazine]

A Banner Year for Astrobiology in Discover Magazine's Top 100 Stories of 2008

January 12, 2009 / Posted by: Daniella Scalice

NAI-funded research confirming the presence of extraterrestrial nucleobases within the Murchison meteorite featured squarely in the middle of Discover’s annual Top 100 list, coming in at number 50. Researchers from NAI’s NASA Goddard Space Flight Center Team contributed to the remarkable study, the results of which imply that the building blocks of life could be widespread throughout the universe. Other stories of astrobiological significance anchored the list on both ends: the confirmation of water ice on Mars by NASA’s Phoenix lander—number 6; and the detection of hydrocarbons in the icy jets of Enceladus by NASA’s Cassini spacecraft—number 95.

Astrobiology Summer Science Experience for Teachers (ASSET)

January 12, 2009 / Posted by: Daniella Scalice

ASSET, produced by the SETI Institute, is a science and curriculum institute for high school science teachers focused on the 9th grade curriculum, Voyages Through Time. The ASSET experience, held at San Francisco State University from 15-20 June 2009, will be intense and exciting, interactive and content rich, with presentations by leading astrobiology researchers from the SETI Institute, NASA, and California Academy of Sciences. Participants receive a copy of VTT. All expenses are covered by grant funds. Applications accepted January 5 – February 20, 2009.

NAI Scientist Elected AAAS Fellow

January 5, 2009 / Posted by: Daniella Scalice

Please join NAI in congratulating Jim Elser of the new Arizona State University (ASU) Team on his election as Fellow of the American Association for the Advancement of Science (AAAS). He and the other newly elected fellows will be recognized Feb. 14 at the Fellows forum, during the 2009 AAAS annual meeting in Chicago.

Becoming a Fellow is in recognition of efforts toward advancing science applications that are deemed scientifically or socially distinguished. Within that general framework, each awardee is honored for contributions to a specific field.

Elser is cited by AAAS for “pioneering work in developing the theories of ecological and biological stoichiometry to integrate levels of biology from the genome to the biosphere and thereby improve our management of renewable resources.” Elser, a professor in the School of Life Sciences at ASU, has built a career asking questions about evolutionary biology and energy and material flows in ecosystems, traveling from Antarctica to alpine lakes of Norway and Colorado to the Mongolian grasslands of China, to find answers. Understanding the balance of carbon, nitrogen and phosphorus in systems forms the backbone of Elser’s worldview, known as “stoichiometric theory.” He has taught more than 10,000 students and his pioneering studies have shaped young minds and jumpstarted new research approaches, as well as provided insights into nutrient limitation, trophic dynamics, and biogeochemical cycling, evolution and integrated levels of organization from molecules to cells to ecosystems.

Source: [Arizona State University Press Release]

Examining a SLIce of the Arctic

January 5, 2009 / Written by: Henry Bortman

NASA-funded researchers have trekked to the arctic island of Svalbard in order to study how life survives in ice. Their research is also helping scientists develop new methods for detecting the presence of ice-dwelling organisms. The SLIce project will help astrobiologists understand how to identify life in surface ice on Earth in preparation for future missions to search for life on other planets, like Mars.

Source: [Astrobiology Magazine]

Astrobiology Top 10

December 24, 2008 / Posted by: Aaron Gronstal

As 2008 draws to a close, the NASA Astrobiology Magazine reviews the top ten astrobiology stories of the year. The topics range from the discovery of ancient organisms preserved in salt crystals to the ethane lakes of Titan, and cover some of the most significant scientific findings in the science of astrobiology over the past 12 months.

Source: [Astrobiology Magazine]

Planets Form in the Eye of the Storm

December 16, 2008 / Posted by: Aaron Gronstal

Astronomers have found that turbulence may play a critical role in creating optimal conditions for the birth of new planets. The study could have implications for theories of planetary formation. Understanding how planets form is essential for scientists trying to identify stars that might host habitable planets.

Source: [Astrobiology Magazine]