Synthesis of prebiotic hydrocarbons may have occurred in impacts of simple icy mixtures on early Earth. Credit: DOE/Lawrence Livermore National Laboratory
LIVERMORE, Calif., June 6 (UPI) -- Early Earth wasn't very hospitable when it came to starting life, U.S. and Canadian scientists say, so life on the planet may have come from out of this world.
Lawrence Livermore scientist Nir Goldman and University of Ontario Institute of Technology colleague Isaac Tamblyn say they've determined icy comets that crashed into Earth millions of years ago could have produced life-building organic compounds, including the building blocks of proteins and nucleobases pairs of DNA and RNA.
Simple molecules such as water, ammonia, methanol and carbon dioxide are found in comets and an impact with Earth would have provided an abundant supply of energy to drive chemical reactions, they said.
"The flux of organic matter to Earth via comets and asteroids during periods of heavy bombardment may have been as high as 10 trillion kilograms (22 trillion pounds) per year, delivering up to several orders of magnitude greater mass of organics than what likely pre-existed on the planet," Goldman said in a Livermore lab release Thursday.
In earlier work in 2010, Goldman used computer models to simulate the chemical reactions comet impacts could have initiated, but could only simulate very short segments of a collision event.
Using new simulations developed on LLNL supercomputers, Goldman has been able to model much longer segments of the impacts, much closer to chemical equilibrium that would have been the result.
"As a result, we now observe very different and a wider array of hydrocarbon chemical products that, upon impact, could have created organic material that eventually led to life," Goldman said. "Cometary impacts could result in the synthesis of prebiotic molecules without the need for other 'special' conditions, such as the presence of catalysts, UV radiation, or special pre-existing conditions on a planet."
