Icy Particles Of Space May Have Been The Ingredients For Life On Earth
Lawrence LeBlond for redOrbit.com – Your Universe Online
In an effort to better understand how life started on Earth, researchers at NASA’s Jet Propulsion Laboratory in Pasadena, California are cooking up icy concoctions of organisms (carbon-bearing molecules) then zapping them with lasers. The JPL crew’s experiments also provide the first direct look at the organic chemistry that takes place in the chilly regions of our solar system, and even chillier reaches between stars.
Scientists theorize that the basic ingredients of life began their journey to Earth on icy particles from these frigid regions of space. These icy organisms would have found their way into comets and asteroids, and have been carried around the solar system, some making their way to Earth, administering a dose of “prebiotic” ingredients to jump-start life on the third rock from the sun.
While the researchers do not have a clear answer on how icy organisms become slime molds, they say the findings help explain how the process works. Published in the Astrophysical Journal Letters, the study involved lab experiments to show that organic matter can begin the processing it needs to become prebiotic while still frozen in ice.
“The very basic steps needed for the evolution of life may have started in the coldest regions of our universe,” said Murthy Gudipati, lead author of the new study at JPL. “We were surprised to see organic chemistry brewing up on ice, at these very cold temperatures in our lab.”
The carbon-rich organics, called polycyclic aromatic hydrocarbons (PAHs), which were used in the lab experiments, are found on Earth as combustion products–in barbecue pits, candle soot, automobile tailpipes, et al. These PAHs have also been found throughout space in comets and asteroids and other distant cosmic vectors. NASA’s Spitzer Space Telescope has even detected PAHs in the swirling planet-forming disks around stars, the spaces between stars, and in the remoteness of distant galaxies.
Gudipati and his colleague, Rui Yang, also of JPL, used a lab setup to mimic the environment of icy PAH molecules found in the frigidness of space, at temperatures hovering around -450 degrees Fahrenheit. To replicate these conditions, the team first bombarded the particles with ultraviolet radiation similar to what is found emitted from stars. They then used a type of laser system known as MALDI (Matrix Assisted Laser Desorption and Ionization) to determine the products of the chemical reaction.
Their results showed that the PAHs had transformed into hydrogen atoms–losing their circular, aromatic bonds and becoming more complex organics. This is the type of change needed if the material were to eventually become amino acids and nucleotides–bits and pieces of protein and DNA, respectively, explained Gudipati.
“PAHs are strong, stubborn molecules, so we were surprised to see them undergoing these chemical changes at such freezing-cold temperatures,” said Gudipati.
The results of this new experiment teaches us that life’s journey may have begun in the vast, cold reaches of the universe. Yet, one question remains: Did it arise elsewhere beyond our sun, too?
Researchers do not yet have an answer for this conundrum, but studies like this one help in the ongoing search for life beyond our planet.