28-March-2008, 02:46 PM
|
 |
Senior Member
|
|
Join Date: Mar 2004
Posts: 10,769
|
|
Neil deGrasse Tyson: Water, Water
Quote:
Starting in the solar system, if you seek a waterless, airless place to visit then you needn't look farther than Earth's Moon. Water swiftly evaporates in the Moon's near-zero atmospheric pressure and its two-week-long, 200 degree Fahrenheit days. During the two-week night, the temperature can drop to 250 degrees below zero, a condition that would freeze practically anything.
[...] Recent evidence from the Clementine lunar orbiter strongly supports a long-held contention that there may be frozen lakes lurking at the bottom of deep craters near the Moon's north and south poles. Assuming the Moon suffers an average number of impacts per year from interplanetary flotsam, then the mixture of impactors should include sizable water-rich comets. How big? The solar system contains plenty of comets that, when melted, could make a puddle the size of lake Erie.
While one wouldn't expect a freshly laid lake to survive many sun-baked lunar days at 200 degrees, any comet that happened to crash in the bottom of a deep crater near the poles (or happened to make a deep polar crater itself), would remain in darkness because deep craters near the poles are the only places on the Moon where the "Sun don't shine."
|
__________________
0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 ....
Last edited by 01101001; 28-March-2008 at 03:59 PM.
|