The findings do not prove that this is how life started on Earth about 4 billion years ago, and some scientists were unimpressed with the results. But the experiment does bolster the long-held theory.

The researchers zapped clay and a chemical soup with the laser to simulate the energy of a speeding asteroid smashing into the planet. They ended up creating what can be considered crucial pieces of the building blocks of life.

WASHINGTON — Scientists in a lab used a powerful laser to recreate what might have been the original spark of life on Earth.

''These findings suggest that the emergence of terrestrial life is not the result of an accident but a direct consequence of the conditions on the primordial Earth and its surroundings,'' the researchers concluded in the study published Monday in the journal Proceedings of the National Academy of Sciences.


The laser-zapping produced all four chemical bases needed to make RNA, a simpler relative of DNA, the blueprint of life. From these bases, there are many still-mysterious steps that must happen for life to emerge. But this is a potential starting point in that process.

Outside experts were divided about the importance of the experiment.

Steve Benner, a biological chemist at the Foundation for Applied Molecular Evolution in Florida, said it is quite relevant because it produced the starting material that would have been around in an early Earth.

But John Sutherland of the MRC Laboratory of Molecular Biology in Cambridge, England, said the amount produced of one base was so small that the results don't seem relevant. Other researchers also downplayed the work.

An alternative theory of early life on Earth says that microbes arrived here from space aboard a comet or an asteroid — a sort of seed theory of life. Civis's work bolsters what would instead be a fire theory of life. It is a theory of both creation and destruction.