26. What three countries have the greatest number of historically active volcanoes?
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?
29. How much of the Earth’s land surface is desert?
30. What's the deepest place in the ocean?
31. How much fresh water is stored in the Earth?
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.
34. What is the world’s deepest lake?
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?
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?
41. How much gold has been discovered worldwide to date?
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?
46. What percentage of the world’s fresh water is stored as glacial ice?
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.
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.
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.