Amazing Earth Facts - VII

37. What percentage of the world's water is in the oceans?

About 97 percent. Oceans make up about two-thirds of Earth's surface, which means that when the next asteroid hits the planet, odds are good it will splash down.

38. Which two landmasses contain the vast majority of the Earth's fresh water supply?

Nearly 70 percent of the Earth's fresh-water supply is locked up in the icecaps of Antarctica and Greenland. The remaining fresh-water supply exists in the atmosphere, streams, lakes, or groundwater and accounts for a mere 1 percent of the Earth's total.

39. Which of the Earth's oceans is the largest?

The Pacific Ocean covers 64 million square miles (165 million square kilometers). It is more than two times the size of the Atlantic. It has an average depth of 2.4 miles (3.9 kilometers).

40. Why is Earth mostly crater-free compared to the pockmarked Moon?

Earth is more active, in terms of both geology and weather. Much of our planet's geologic history was long ago folded back inside. Some of that is regurgitated by volcanoes, but the results are pretty hard to study. Even more recent events evident on the surface -- craters that can by millions of years old -- get overgrown by vegetation, weathered by wind and rain, and modified by earthquakes and landslides. The Moon, meanwhile, is geologically quiet and has almost no weather; its craters tell a billions-year-long tale of catastrophic collisions. Interestingly, some of the oldest Earth rocks might be awaiting discovery on the Moon, having been blasted there billions of years ago by the very asteroid impacts that rattle both worlds.

41. How much surface area does Earth contain?

There are 196,950,711 square miles (510,100,000 square kilometers).

42. What is the largest lake in the world?

By size and volume it is the Caspian Sea, located between southeast Europe and west Asia.