Space Dust Is Filled with Amino acids, the Building Blocks for Life

Life's building blocks were found in a much smaller sample of the so-called "Murchison meteorite" than before, as this diagram shows. 

Credit: Michael Callahan

A study of teeny-tiny meteorite fragments revealed that two essential components of life on Earth as we know it, could have migrated to our planet on space dust.

Researchers at Goddard's Astrobiology Analytical Lab discovered DNA and amino acids components in a smidgen of a space rock that fell over Murchison, Victoria, in Australia in September 1969.

Previous studies of the meteorite revealed organic material, but the samples examined then were much larger.

This study would lend more credence to the idea that life arose from outside of our planet, researchers said in a statement.

Michael Callahan

"Despite their small size, these interplanetary dust particles may have provided higher quantities and a steadier supply of extraterrestrial organic material to early Earth," said Michael Callahan, a research physical scientist at NASA's Goddard Space Flight Center in Greenbelt, Md.

Amino acids are the basis of proteins, which are structures that make up hair, skin and other bits of living creatures.

DNA is a molecule that contains information on building and running an organism.

This equipment is used by Goddard's Astrobiology Analytical Lab to analyze very small samples. 

On the right is the nanoelectrospray emitter, which gives sample molecules an electric charge and transfers them to the inlet of the mass spectrometer (left), which identifies the molecules by their mass. 

Image Credit: Michael Callahan

Size matters
Meteorites such as Murchison are rare types of space rocks: the carbonaceous chondrites make up less than 5 percent of meteorites found on Earth, NASA said.

Further, the molecules discovered in these space rocks are usually in miniscule concentrations of parts-per-million or parts-per-billion.

These factors have researchers questioning how significant the carbon-rich rocks themselves were in bringing life to Earth.

Space dust, however, is more plentiful as it is constantly available from comets and asteroids shedding debris in their travels through the solar system.

The Murchison study (a proof of concept for further work, the researchers say) found life's building blocks in a sample that weighed about the same as a few eyebrow hairs.

The 360-microgram sample was about 1,000 times smaller than a typical sample analyzed by researchers.

Samples from space
This micro-sample required a more sensitive technique than usual to extract the information scientists needed.

A nanoflow liquid chromatography instrument organized the molecules, which were then ionized with a nanoelectrospray for analysis in a mass spectrometer.

NASA and other agencies have dealt with small sample sizes before, such as on the Stardust mission that collected particles from Comet Wild-2 and returned them to Earth in 2006.

Researchers anticipate the techniques they are using today could be used for other missions in the solar system, especially for sample-return missions.

"This technology will also be extremely useful to search for amino acids and other potential chemical biosignatures in samples returned from Mars and eventually plume materials from the outer planet icy moons Enceladus and Europa," said Goddard astrobiologist Daniel Glavin, who was co-author on the research.

The study, led by Callahan, was recently published in the Journal of Chromatography A.

More Information: 'Amino acid analysis in micrograms of meteorite sample by nanoliquid chromatography–high-resolution mass spectrometry': Michael P. Callahana, Corresponding author contact information, E-mail the corresponding author, Mildred G. Martinb, Aaron S. Burtonc, 1, Daniel P. Glavina, Jason P. Dworkina: dx.doi.org/10.1016/j.chroma.2014.01.032

Has NASA's Curiosity Rover Found Clues to Life's Building Blocks on Mars?

This patch of windblown sand and dust downhill from a cluster of dark rocks is the 'Rocknest' site studied by NASA’s Mars rover Curiosity. 

The Rocknest patch is about 8 feet by 16 feet (1.5 meters by 5 meters) and may contain perchlorate salts. Image added April 1, 2013.

CREDIT: NASA/JPL-Caltech/MSSS

NASA's Mars rover Curiosity just might be the latest in a long line of Mars-exploring robots to discover the building blocks for primitive life on the Red Planet.

The Curiosity rover may have gathered evidence for the presence of perchlorates in Rocknest — a sand patch inside the rover's Gale Crater landing site on the Red Planet, scientists say. If so, it shores up the case that the material may well be globally distributed on Mars.

Not only can perchlorates, which are a class of salts, serve as an energy source for potential Martian microorganisms, they are also a sensitive marker of past climate and can lead to the formation of liquid brines under current conditions on the planet.

The possibility that perchlorates are widespread on Mars was detailed in a March 18 presentation at the 44th annual Lunar and Planetary Science Conference in The Woodlands, Texas.


Curiosity's possible detection
The possible detection of perchlorates at Curiosity’s Gale crater site was spotlighted by Doug Archer, a scientist with the Astromaterials Research and Exploration Science Directorate of NASA's Johnson Space Center in Houston. He is focused on the habitability of various Martian environments over time. [The Search for Life on Mars

Archer pointed to the rover’s Sample Analysis at Mars (SAM) instrument suite that recently ran four samples from Rocknest. That area was selected as the source of the first samples analyzed because it is representative of both windblown material in the Gale Crater and the planet's globally distributed dust, he said.

"When we heated this up, we saw a large oxygen release at the same time we saw the release of these chlorinated hydrocarbons," Archer said, thus making a strong case for the presence of perchlorate salts in Rocknest's soil.