宇宙的秘密（英文）谁知道怎么写？

Space radiation preferentially destroys specific forms of amino acids, the most realistic laboratory simulation to date has found. The work suggests the molecular building blocks that form the "left-handed" proteins used by life on Earth took shape in space, bolstering the case that they could have seeded life on other planets.

Amino acids are molecules that come in mirror-image right- and left-handed forms. But all the naturally occurring proteins in organisms on Earth use the left-handed forms - a puzzle dubbed the "chirality problem".

"A key question is when this chirality came into play," says Uwe Meierhenrich, a chemist at the University of Nice-Sophia Antipolis in France. One theory is that proteins made of both types of amino acids existed on the early Earth but "somehow only the proteins of left-handed amino acids survived", says Meierhenrich.

Meierhenrich and colleagues have a different theory. &quo