Toward the end of the Eocene epoch 35 million years ago, temperatures plummeted and the Earth's primitive inhabitants endured a cold spell that lasted 100,000 years. The length of that ordeal and what brought it on have long puzzled experts. Various theories to explain it have been put forward--from variations in solar output to changes in the tilt of the Earth's axis--and generally dismissed. Now two scientists, writing in the Journal of Geophysical Research, have proposed a novel idea: the possibility that our planet was once encircled by a huge, Saturn-like ring created by a glancing blow from an asteroid.
It...
To continue reading:
or
Log-In
