Quantcast
Last updated on April 17, 2014 at 1:21 EDT

Latest Francois Paquay Stories

2008-04-10 16:22:37

Asteroids that strike Earth have cosmic origins, but clues to the size of ancient impactors now have come from a decidedly Earth-bound source: the chemistry of ancient seawater. Asteroids and other extraterrestrial objects have struck Earth countless times over its multi-billion-year history, but most have left little visible trace. Though these cosmic projectiles pack a wallop when they collide with our planet, they often vaporize on impact or fall into the ocean, making it...