Barry Evans ("Kickstarting Life," Nov.10) presented Steven Benner's theory that life originated on Mars and was transported to Earth via Martian meteorites. I wish to restore some faith in the simpler terrestrial explanation by quoting the following from Wikipedia:
"Benner suggested that Mars may have had more desirable conditions than Earth for the initial production of RNA, but more recently agreed that models of early Earth showing dry land and intermittent water, developed by Stephen Mojzsis, present sufficient conditions for RNA development."
The Earth had such a vast variety of environments and such vast expanses of time that almost any conceivable chemistry would have taken place somewhere at some time. Life did arise, so it was clearly possible.
Don Garlick, Fieldbrook