New Analysis of Stardust Provides Evidence of Life's Ingredients

Stardust may provide a steady supply of organic material to Earth, which would have jump started the beginnings of life on this planet, according to NASA researchers.

The findings, published in the Journal of Chromatography A, come after the development of advanced technology allowed Michael Callahan and his team at Goddard's Astrobiology Analytical Laboratory to inspect tiny meteorite samples for components of life.

"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 Callahan in a report from NASA. "Unfortunately, there have been limited studies examining their organic composition, especially with regards to biologically relevant molecules that may have been important for the origin of life, due to the miniscule size of these samples."

In the past, researchers have inspected carbon-rich meteorites and found amino acids and components of DNA, which are both necessary for life. However, these carbon-rich meteorites make up less than 5 percent of recovered meteorites, and meteorites only make up a portion of extraterrestrial material that reaches the Earth's surface.

Using new analytic techniques, Callahan was able to show that organic material is transported to Earth's surface on a wider variety of matter from space.

"We found amino acids in a 360 microgram sample of the Murchison meteorite," Callahan said, referring to an often-studied meterorite. "This sample size is 1,000 times smaller than the typical sample size used." A microgram is one-millionth of a gram, so Callahan was studying samples that had the approximate weight of a few eyebrow hairs.

These results are significant because it allows for the possibility of extraterrestrial material playing a larger role in the beginnings of life on Earth than previously thought.

"Our study was for proof-of-concept," added Callahan. "Murchison is a well-studied meteorite. We got the same results looking at a very small fragment as we did a much larger fragment from the same meteorite.These techniques will allow us to investigate other small-scale extraterrestrial materials such as micrometeorites, interplanetary dust particles, and cometary particles in future studies."

The team used a nanoflow liquid chromatography instrument to sort the molecules, then applied nanoelectrospray ionization to give the molecules an electric charge and finally identified the molecules based on their mass.

Callahan stated he is interested in analyzing cometary particles from NASA's Stardust mission, while his co-author, Daniel Glavin, said he is looking forward to using the technique on samples from Mars.

"Missions involving the collection of extraterrestrial material for sample return to Earth usually collect only a very small amount and the samples themselves can be extremely small as well," Callahan said. "The traditional techniques used to study these materials usually involve inorganic or elemental composition. Targeting biologically relevant molecules in these samples is not routine yet. We are not there either, but we are getting there."

Further Reading: Irradiated Space Dust Carries Water to Earth and Other Planets