Why is Earth so dry?
Tuesday, July 17, 2012 - 14:00
in Astronomy & Space
(Phys.org) -- With large swaths of oceans, rivers that snake for hundreds of miles, and behemoth glaciers near the north and south poles, Earth doesn't seem to have a water shortage. And yet, less than one percent of our planet's mass is locked up in water, and even that may have been delivered by comets and asteroids after Earth's initial formation.