Comets carried noble gases to Earth
Measurement of argon on Comet 67P prompts new theory of space projectiles’ role
Asteroids probably ferried water to an infant Earth (SN: 5/16/15, p. 18), but they weren’t responsible for our planet’s entire chemical inventory. Comets might have trucked in noble gases and much of the raw material needed for life, researchers suggest online March 9 in Earth and Planetary Science Letters.
Noble gases don’t play well with the other elements. They typically shun chemical reactions, which means their abundances haven’t changed much since the formation of the solar system. Comets are thought to be frozen relics from the birth of the planets, but until recently researchers didn’t know how much of any noble gas comets carried.