|
| Cosmic radiation |
Manageable, protection courtesy a strong magnetic field. |
Problematic, due to a weak magnetic field. |
| Weather |
Hurricanes, typhoons and tornadoes a real problem.
Disgustingly interminable fog in coastal California. Utter lack of rain
in parts of Africa. Way too wet in many other places. |
Dust storms abound. Sometimes whole planet is
obscured. Dust devils that soar higher into the atmosphere than
terrestrial tornadoes and hurricane-like storms as big as Texas. |
| Heft |
1 Earth mass. In kilograms, it's about 6 with twenty-four zeros after it. |
About 10.7 percent that of Earth. |
| Biggest mystery |
How life began. |
Whether there is life. |
| Biggest hoax |
The one suggesting we didn't really go to the Moon. |
The purported Face. |
| Day |
23 hours, 56 minutes. |
24 hours, 37 minutes. |
| Year |
365 days (the time needed to go around the Sun once). |
687 Earth-days, or about 670 Mars days. |
| Gravity |
Normal. |
38 percent of that found on Earth at sea level. |
| Tilt of rotation axis |
23.5 degrees. |
25 degrees. |
| Satellites |
The Moon, plus several that communicate, and tons of junk as small as paint chips. |
Two natural ones, Phobos and Deimos, plus two sent by NASA and more on the way. |
| Air |
Quite a bit. About 76 percent of it is nitrogen,
with about 21 percent oxygen. Next most common, in order but in very
small amounts: Argon, carbon dioxide, neon. |
Not much. Less than 1 percent the density of Earth's
air at the surface, and mostly carbon dioxide (95.3 percent). Trace of
oxygen (0.15%). |
| Volcanic hazards |
Wrong place, wrong time. Say goodbye. Close? Take a photo. |
Nothing but remnants of former beasts soaring silently into thin air. |
| Caves |
Many, and they're great places for microbial life to hide. |
Maybe, and they're possible places for humans to hide. |
| Snow |
Tons. Like 1,140 inches at Washington's Mt. Baker during the 1998-99 season, a world record. That's 95 feet (29 meters). |
Yes, surprisingly, but you wouldn't want to ski on it. And it's melting, perhaps due to global warming. |
| Water ice |
Yes, often invisible and under moving car tires. |
Yes, much of it invisible and under the surface or beneath another kind of ice at the south pole. |
| Dry ice |
Sure. 4,200 pounds of it is used weekly in just one Vegas show. |
Tons, covering the water ice at the south pole. |
| Water |
Inundates the place, especially in basements and during picnics. |
Lots in the frozen form. And possibly plenty of the liquid type long ago. |
| Best photo |
The Blue Marble. |
Couldn't decide, so we had experts pick 10 |
