50 Amazing Earth Facts to Know - Part II

25. What is the largest lake in the world?

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

26. What three countries have the greatest number of historically active volcanoes?

The top three countries are Indonesia, Japan, and the United States in descending order of activity.
27. How many people worldwide are at risk from volcanoes?

As of the year 2000, USGS scientists estimated that volcanoes posed a tangible risk to at least 500 million people. This is comparable to the entire population of the world at the beginning of the seventeenth century!

28. Does all of Earth spin at the same rate?

The solid inner core -- a mass of iron comparable to the size of the Moon -- spins faster than the outer portion of the iron core, which is liquid. A study in 1996 showed that over the previous century, the extra speed caused the inner core to gain a quarter-turn on the planet as a whole. So the inner core makes a complete revolution with respect to the rest of Earth in about 400 years. Immense pressure keeps it solid.
29. How much of the Earth’s land surface is desert?

About one-third.

30. What's the deepest place in the ocean?

The greatest known depth is 36,198 feet (6.9 miles or 11 kilometers) at the Mariana Trench, in the Pacific Ocean well south of Japan near the Mariana Islands.
31. How much fresh water is stored in the Earth?

More than two million cubic miles of fresh water is stored in the planet, nearly half of it within a half-mile of the surface. Mars, too, appears to have a lot of water near its surface, but what's been detected so far is locked up as ice; nobody has estimated how much might be there.
32. How old is Earth?

Our planet is more than 4.5 billion years old, just a shade younger than the Sun. Recent evidence actually shows that Earth was formed much earlier than previously believed, just 10 million years after the birth of the Sun, a stellar event typically put at 4.6 billion years ago.

33. What is the world’s largest desert?

The Sahara Desert in northern Africa is more than 23 times the size of southern California’s Mojave Desert. [Several readers have e-mailed to suggest that arid Antarctica technically tops this category; true, some researchers put it there, but most lists of deserts don't include it.]
34. What is the world’s deepest lake?

Lake Baikal in the south central part of Siberia is 5,712 feet (1.7 kilometers) deep. It's about 20 million years old and contains 20 percent of Earth's fresh liquid water.
35. What is the origin of the word "volcano"?

It derives from Vulcan, the Roman god of fire.

36. What is the total water supply of the world?

The total water supply of the world is 326 million cubic miles (1 cubic mile of water equals more than 1 trillion gallons).

37. What is the world’s largest island?

Greenland covers 840,000 square miles (2,176,000 square kilometers). Continents are typically defined as landmasses made of low-density rock that essentially floats on the molten material below. Greenland fits this description, but it's only about one-third the size of Australia. Some scientists call Greenland an island, others say it's a continent.

38. What volcano killed the most people?

The eruption of Tambora volcano in Indonesia in 1815 is estimated to have killed 90,000 people. Most died from starvation after the eruption, though, because of widespread crop destruction, and from water contamination and disease.

39. Is ice a mineral?

Yes, ice is a mineral and is formally described as such in Dana's System of Mineralogy.

40. What is the longest mountain chain on Earth?

The Mid-Atlantic Ridge, which splits nearly the entire Atlantic Ocean north to south. Iceland is one place where this submarine mountain chain rises above the sea surface.
41. How much gold has been discovered worldwide to date?

More than 193,000 metric tons (425 million pounds). If you stuck it all together, it would make a cube-shaped, seven-story structure that might resemble one of Donald Trump's buildings. First you'd have to find all those rings that have gone down the drain.

42. What are the two major gold-producing countries?

South Africa produces 5,300 metric tons per year, and the United States produces more than 3,200 metric tons.
43. On average, how much water is used worldwide each day?

About 400 billion gallons.

44. What is the highest, driest, and coldest continent on Earth?

That would be Antarctica.

45. Where are the oldest rocks on Earth found?

Since the ocean floor is being continually regenerated as the continental plates move across the Earth’s surface, the oldest rocks on the ocean floor are less than 300 million years. In contrast, the oldest continental rocks are 4.5 billion years old.

46. What percentage of the world’s fresh water is stored as glacial ice?

About 70 percent. And if you had to replace it all, you'd need 60 years of the entire globe's rainfall, and then you'd have to figure out a way to freeze it all.

47. How much volcanic ash can fall in a day?

I can only give an example. During the 9-hour period of most vigorous activity on May 18, 1980, Mount St. Helens dumped more than 540 million tons of ash over an area of more than 22,000 square miles (56,980 square kilometers). It was the most destructive volcanic eruption known to occur in the United States. Fifty-seven people were killed by the eruption including USGS scientist Dr. David Johnston, who was at a monitoring site 5 miles (8 kilometers) from the volcano. An estimated $1 billion damage was caused by the eruption, through mudflows and landslides as well as what fell from the sky.

48. What are the most extreme locations in the United States, compass-wise?

This one is a bit tricky, and as it turns out three or even four of the answers may catch you off guard. The westernmost point is the aptly named West Point of Amatignak Island, Alaska. The northernmost point is Point Barrow, Alaska. The southernmost point is the southern tip of the island of Hawaii. The easternmost point -- go ahead, take a guess! -- is Pochnoi Point at Semisopochnoi, Alaska. Huh? Look at a world map. The tip of the Aleutian Islands lies on the other side of the 180-degree longitude line --- the International Dateline -- putting Pochnoi Point barely but officially in the Eastern Hemisphere.

49. If you were to arrange Earth, the Moon and Mars like Matryoshka nesting dolls, how would they be ordered?

Mars would nest inside Earth, and the Moon would fit neatly inside Mars. Earth is about twice as big as Mars, which is about twice as big as the Moon.

50. Will Earth always be here?

Astronomers know that over the next few billion years, the Sun will swell so large as to envelop Earth. If we're still here, we'll probably fry and the planet will be vaporized. There's a chance, however, that the changing mass of the Sun will cause Earth to move into a more distant and pleasant orbit. One mathematical calculation shows it would be theoretically possible for humans to engineer such a move before it's too late.