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Message: <blockquote data-quote="Novindu" data-source="post: 12101" data-attributes="member: 718">PART 251. 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. 52. How many people have been killed by volcanoes during the last 500 years?At least 300,000. Between 1980 and 1990, volcanic activity killed at least 26,000 people.53. How much of the Earth's surface consists of volcanic rock?Scientists estimate that more than three-quarters of Earth's surface is of volcanic origin-- that is, rocks either erupted by volcanoes or molten rock that cooled below ground and has subsequently been exposed at the surface. Most of Earth's volcanic rocks are found on the sea floor. 54. Can an earthquake cause a tsunami?If the earthquake originates under the ocean, yes. Near the earthquake's epicenter, the sea floor rises and falls, pushing all the water above it up and down. This motion produces a wave that travels outward in all directions. A tsunami can be massive but remain relatively low in height in deep water. Upon nearing the shore, it is forced up and can reach the height of tall buildings. One in 1964 was triggered in Alaska and swamped the small northern California town of Crescent City, moving train cars several blocks and killing several people there. Asteroids can cause tsunami , too. 55. Are all tsunamis high waves when they strike a coastline? Asteroid-generated tsunami No, contrary to many artistic images of tsunamis, most do not result in giant breaking waves. Rather, most tsunamis come onshore more like very strong and fast tides. The water can rise higher than anyone along a given shore area has ever seen, however . [Model of an East Coast tsunami ]56. How much of the Earth's land surface is desert?About one-third.57. 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.58. What is the fastest surface wind ever recorded?The fastest "regular" wind that's widely agreed upon was 231 mph (372 kph), recorded at Mount Washington, New Hampshire, on April 12, 1934. But during a May 1999 tornado in Oklahoma, researchers clocked the wind at 318 mph (513 kph). For comparison, Neptune's winds can rage to 900 mph (1,448 kph). 59. 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.60. 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.61. 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.] 62. Which planet has more moons, Earth or Mars?Mars has two satellites, Phobos and Deimos. The Earth has only one natural satellite, but it's the Moon. The outer planets have lots of Moon, most of them found fairly recently and leading to the possibility that scientists might one day need to redefine what it means to be a moon.63. 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.64. What is the origin of the word "volcano"?It derives from Vulcan, the Roman god of fire.65. How many minerals are known to exist?There are roughly 4,000 known minerals, although only about 200 are of major importance. Approximately 50-100 new minerals are described each year.66. 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).67. 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.  68. Where are most of Earth's volcanoes?The most prominent topographic feature on Earth is the immense volcanic mountain chain that encircles the planet beneath the sea -- the chain is more than 30,000 miles (48,000 kilometers) long and rises an average of 18,000 feet ( 5.5 kilometers) above the seafloor. It is called the mid-ocean ridge and is where Earth's plates spread apart as new crust bubbles up -- volcanic activity. There are more volcanoes here than on land. The spreading, however, leads to scrunching when these plates slam into the continents. The result: More volcanoes and earthquakes in places like California and Japan. 69. 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. 70. Were Earth and the Moon separated at birth?Not quite. But leading theory holds that our favorite satellite was carved partly from Earth shortly after the Earth formed. A Mars-sized object slammed into our fledgling planet. The impactor was destroyed. Stuff flew everywhere and a lot of it went into orbit around Earth. The Moon gathered itself together out of the largely vaporized remains of the collision, while Earth hung in there pretty much intact. 71. How many lightning strikes occur worldwide every second?On average, about 100. Those are just the ones that hit the ground, though. During any given minute, there are more than a thousand thunderstorms around the Earth causing some 6,000 flashes of lightning. A lot of it goes from cloud-to-cloud. 72. Are rivers alive?Not in the traditional sense, of course. But like all living creatures, rivers have a life span. They are born, grow in size, and they age. They can even die during the span of geological time.73. Can asteroids create islands?Speculation has existed for decades that ancient asteroid impacts might create hot spots of volcanic activity, which could give rise to mountains that poke up through seas that didn't used to be there. There's no firm answer to this question, but a recent computer model suggested Hawaii might have been formed in this manner . 74. Is the state of Louisiana growing or shrinking?Louisiana loses about 30 square miles (78 square kilometers) of land each year to coastal erosion, hurricanes, other natural and human causes and a thing called subsidence, which means sinking. Much of New Orleans actually sits 11 feet ( 3.4 meters) below sea level. Parts of the French quarter have sunk 2 feet in the past six decades. The city is protected by dikes, but all experts agree that storm tides from a direct hit by a major hurricane would breach the system and swamp much of the city. In 2000, the director of the U.S. Geological Survey, Chip Groat, said: "With the projected rate of subsidence, wetland loss and sea-level rise, New Orleans will likely be on the verge of extinction by this time next century." 75. How much would seas rise if the Antarctic Ice Sheet melted?The Antarctic Ice Sheet holds nearly 90 percent of the world's ice and 70 percent of its fresh water. If the entire ice sheet were to melt, sea level would rise by nearly 220 feet, or the height of a 20-story building. Scientists know there's a melting trend underway. The United Nations has said that in a worst-case scenario -- depending on how much global air temperatures increase -- seas could jump 3 feet (1 meter) by 2100.77. Is ice a mineral?Yes, ice is a mineral and is formally described as such in Dana's System of Mineralogy.77. What is the softest of all minerals?Talc is the softest of minerals. It is commonly used to make talcum powder.78. What is the hardest of all minerals?The one that becomes emotionally useless after a divorce but still retains monetary value.79. How are colors produced in fireworks?Mineral elements taken from Earth provide the colors. Strontium yields deep reds, copper produces blue, sodium yields yellow, and iron filings and charcoal pieces produce gold sparks. Bright flashes and loud bangs come from aluminum powder. 80. Does Earth have the worst weather in the solar system?Right now, it's the worst that most humans I know ever experience. But there's lots of wilder weather elsewhere. Mars can whip up hurricane-like storms four times bigger than Texas. Dust storms on the red planet can obscure the entire globe! Jupiter has a hurricane twice the size our entire planet, and it's lasted for at least three centuries ( another storm on Jupiter is even bigger). Venus is a living hell, and Pluto is routinely more frigid than the coldest place on Earth (though may change one day, and Pluto may in fact become the last oasis for life). 81. Where are the highest tides?In Burntcoat Head, Minas Basin, part of the Bay of Fundy in Nova Scotia, tides can range 38.4 feet (11.7 meters). The bay is funnel shaped -- its bottom slopes upward continuously from the ocean inlet. The result is an extreme "tidal bore," a wave-like phenomenon at the leading edge of the changing tide. Bores in Fundy can travel up feeder rivers at 8 mph (13 kph) and be more than 3 feet (1 meter) tall. 82. Where is the world's only equatorial glacier?Mt. Cotopaxi in Ecuador supports the only glacier on the equator.83. What is the largest lake in North America?Lake Superior.84. What's the deadliest hurricane to ever hit the United States?A Category 4 hurricane hit Galveston, Texas in 1900 and killed more than 6,000 people (read about the history of it here). The next closest death toll was less than 1,900 from a 1928 Florida hurricane.85. 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. 86. 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. 87. 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. 88. What North American plant can live for thousands of years?The creosote bush, which grows in the Mojave, Sonoran, and Chihuahuan deserts, has been shown by radiocarbon dating to have lived since the birth of Christ. Some of these plants may endure 10,000 years, scientists say. If only they could talk. 89. On average, how much water is used worldwide each day?About 400 billion gallons.90. Is Saturn the only ringed planet?Saturn has the most obvious rings. But Jupiter and Neptune both have subtle ring systems, [as does Uranus, readers reminded me]. And even Earth may once have been a ringed planet, the result of some space rock's glancing blow.</blockquote>

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