MOON HAD EXPLOSIVE ORIGINS, STUDY CLAIMS.(MAIN)

Byline: LEE BOWMAN Scripps Howard

A collision between the nascent Earth and a rogue planet three times as massive as Mars ejected the material that formed Earth's moon 4.5 billion years ago, according to a new study scheduled to be presented today.

Researchers at the University of Colorado at Boulder and Harvard University set up a new mathematical model for the impact, which has been pretty much accepted as the origin of the moon ever since the Apollo missions returned rock samples for analysis.

But where Harvard scientists in the late 1980s proposed the planet that hit Earth was about as massive as Mars (or one-tenth the mass of Earth), the new …