Astrobiologists Discover Sweet Spots For Formation of Complex Organic Molecules

Scientists within the New York Center for Astrobiology at Rensselaer Polytechnic Institute have compiled years of research to help locate areas in outer space that have extreme potential for complex organic molecule formation.

The scientists searched for methanol, a key ingredient in the synthesis of organic molecules that could lead to life.

Their results have implications for determining the origins of molecules that spark life in the cosmos.

The findings will be published in the Nov. 20 edition of The Astrophysical Journal in a paper titled "Observational constraints on methanol production in interstellar and preplanetary ices."

The work is collaboration between researchers at Rensselaer, NASA Ames Research Center, the SETI Institute, and Ohio State University.

"Methanol formation is the major chemical pathway to complex organic molecules in interstellar space," said the lead researcher of the study and director of the NASA-funded center, Douglas Whittet of Rensselaer.

If scientists can identify regions where conditions are right for rich methanol production, they will be better able to understand where and how the complex organic molecules needed to create life are formed.

In other words, follow the methanol and you may be able to follow the chemistry that leads to life.

Using powerful telescopes on Earth, scientists have observed large concentrations of simple molecules such as carbon monoxide in the clouds that give birth to new stars.

To make more complex organic molecules, hydrogen needs to enter the chemical process. The best way for this chemistry to occur is on the surfaces of tiny dust grains in space, according to Whittet.

In the right conditions, carbon monoxide on the surface of interstellar dust can react at low temperatures with hydrogen to create methanol (CH3OH).

Methanol then serves as an important steppingstone to formation of the much more complex organic molecules that are required to create life.

Scientists have known that methanol is out there, but to date there has been limited detail on where it is most readily produced.

What Whittet and his collaborators have discovered is that methanol is most abundant around a very small number of newly formed stars. Not all young stars reach such potential for organic chemistry.

In fact, the range in methanol concentration varies from negligible amounts in some regions of the interstellar medium to approximately 30 percent of the ices around a handful of newly formed stars.

They also discovered methanol for the first time in low concentrations (1 to 2 percent) in the cold clouds that will eventually give birth to new stars.

The scientists conclude in the paper that there is a "sweet spot" in the physical conditions surrounding some stars that accounts for the large discrepancy in methanol formation in the galaxy.

The complexity of the chemistry depends on how fast certain molecules reach the dust grains surrounding new stars, according to Whittet.

The rate of molecule accumulation on the particles can result in an organic boom or a literal dead end.

NASA Research Shows DNA Building Blocks in Space

NASA-funded researchers have found more evidence meteorites can carry DNA components created in space.

Scientists have detected the building blocks of DNA in meteorites since the 1960s, but were unsure whether they were created in space or resulted from contamination by terrestrial life.

The latest research indicates certain nucleobases, the building blocks of our genetic material, reach the Earth on meteorites in greater diversity and quantity than previously thought.

The discovery adds to a growing body of evidence that the chemistry inside asteroids and comets is capable of making building blocks of essential biological molecules.

Previously, scientists found amino acids in samples of comet Wild 2 from NASA’s Stardust mission and in various carbon-rich meteorites.

Amino acids are used to make proteins, the workhorse molecules of life. Proteins are used in everything from structures such as hair to enzymes, which are the catalysts that speed up or regulate chemical reactions.

The findings will be published in the online edition of the Proceedings of the National Academy of Sciences. In the new work, scientists analyzed samples of 12 carbon-rich meteorites, nine of which were recovered from Antarctica. The team found adenine and guanine, which are components of DNA nucleobases.

Also, in two of the meteorites, the team discovered for the first time trace amounts of three molecules related to nucleobases that almost never are used in biology. These nucleobase-related molecules, called nucleobase analogs, provide the first evidence that the compounds in the meteorites came from space and not terrestrial contamination.

“You would not expect to see these nucleobase analogs if contamination from terrestrial life was the source, because they’re not used in biology,” said Michael Callahan, astrobiologist and lead author of the paper from NASA’s Goddard Space Flight Center in Greenbelt, Md.

“However, if asteroids are behaving like chemical ‘factories’ cranking out prebiotic material, you would expect them to produce many variants of nucleobases, not just the biological ones, because of the wide variety of ingredients and conditions in each asteroid.”

Additional evidence came from research to further rule out the possibility of terrestrial contamination as a source of these molecules. The team analyzed an eight-kilogram (17.6-pound) sample of ice from Antarctica, where most of the meteorites in the study were found.

The amounts of nucleobases found in the ice were much lower than in the meteorites. More significantly, none of the nucleobase analogs were detected in the ice sample. The team also analyzed a soil sample collected near one of the non-Antarctic meteorite’s fall site.

As with the ice sample, the soil sample had none of the nucleobase analogue molecules present in the meteorite.

Launched in Feb. 7, 1999, Stardust flew past an asteroid and traveled halfway to Jupiter to collect particle samples from the comet Wild 2. The spacecraft returned to Earth’s vicinity to drop off a sample-return capsule on January 15, 2006.

The research was funded by NASA’s Astrobiology Institute at the agency’s Ames Research Laboratory in Moffett Field Calif., and the Goddard Center for Astrobiology in Greenbelt, Md.; the NASA Astrobiology Exobiology and Evolutionary Biology Program and the NASA Postdoctoral Program at the agency’s Headquarters in Washington.

Additional information and images are available at: NASA DNA Study

MARS Simulation on Tenerife mountain top

One of the most exciting parts of my astrobiology research is working out how to search for evidence of past Martian life - signs of ancient biology that may have fallen extinct hundreds of millions of years ago.

One promising technique for finding these "biosignatures" - which could be pockets of organic molecules or even microbial life - is to entice them to glow in the dark using an ultraviolet laser mounted on a robotic probe. A camera on the probe would then detect the glow.

If you've ever had a gin and tonic in a nightclub you are probably already familiar with this effect. You'll have noticed how the ultraviolet lights in the club (we see them as black) cause the G&T to emit an eerie blue glow. This is caused by quinine, an organic molecule in the tonic water, fluorescing. It is this bitter-tasting compound that gives tonic water its anti-malarial properties so it's funny to think how far we've come since Victorian colonists in East Africa supped medicinal G&T sun-downers!

I have been testing this technique in the lab but it is now time to try the equipment in a more realistic scenario. So next week I'm flying out to Tenerife in the Canary Islands to carry out fieldwork in the volcanic caldera that sits like a giant pimple on the face of this tiny island. The barren rocky terrain and volcanic geology around Tenerife are a good approximation to the Martian landscape, and, in fact, prototypes for Mars rovers are put through their paces here.

I am part of a team of scientists, lead by Derek Pullan at Leicester University, who will be field-testing different instruments and camera systems. The system I'll be testing involves a sensitive digital camera and an ultraviolet light source. Because we'll be operating by day I'll have to shield everything from the bright sunlight beneath a thick photographic blanket. My rucksack will also be laden with other snazzy kit like a laser range-finder and GPS-equipped camera to record the environment around my test sites.

There are still a few things to sort out, but I'm pretty much good to go now. Holiday snaps to follow!

NASA's Quest for space life a focus for the future

US space agency NASA is pondering 28 potential missions focusing on finding life beyond Earth inside our solar system, a US researcher said Wednesday.

"Astrobiology and the search for life is really central to what we should be doing next in the exploration of the solar system," Steve Squyres, a researcher at Cornell University in Ithaca, New York, said in a telephone press briefing.

"We are looking for a total of 28 different missions.... They cover everything from Mercury landers to fly-by of objects in deep outer space of the solar system -- and they are particularly relevant to looking for life," he explained.

Among other objects of interest: a three-stage Martian mission that would bring Martian soil samples back to Earth, said Squyres, who worked on the Spirit and Opportunity rovers, still active six years after their arrival on the Red Planet.

"Those samples might reveal a great deal of whether Mars once or today (has) forms of life," he said.

Another part of the mission would be to look at the origin of methane in the planet's atmosphere, and whether or not it is organic, he said.

Methane breaks down quickly in the Martian atmosphere, but scientists discovered plumes of methane on Mars in 2003, raising the prospect that the planet is not entirely dead.

"So we will send a mission potentially to look at the sources of the methane and consider the possibility that they could be from biological origins," Squyres added.

Further out in the solar system, scientists are very interested in Europa, a moon of Jupiter, he said.

"It's believed that Europa may have an ocean of liquid water underneath its icy crust. And we are looking at a Europa robot mission that would have, among other things, the capability to use a radar system that can penetrate through that ice, find the ocean if it exists, identify places where you might go to the surface to learn more" about the ocean, Squyres said.

Likewise Titan, a moon of Saturn, has scientists' attention.

It is "a moon we know to be very rich in organic materials. We are looking long term at a mission that will study Titan in great deal, including an orbiter, a balloon in Titan atmosphere and a lander to land in some of the lakes of liquid methane," the Cornell scientist added.

Another mission under consideration is one to return samples from a comet, the researcher said. "Comets are believed to be rich in organic materials, rich in building blocks of life. Most of the organic material on earth was probably delivered to earth by comets."

The number of projects needs to be whittled down, he said, before a recommendation will be made on what missions NASA should prioritise.