EARTH FACTS 1

Amazing Earth Facts
By Robert Roy Britt
Senior Science Writer
(Sources include the U.S. Geological Survey and the National Oceanic and Atmospheric Administration, with other
SPACE.com reporting)
1. What is the hottest place on Earth?
El Azizia in Libya recorded a temperature of 136 degrees Fahrenheit (57.8 Celsius) on Sept. 13, 1922 -- the hottest
ever measured. In Death Valley (California), it got up to 134 Fahrenheit on July 10, 1913.
2. What is the coldest place around here?
The coldest temperature ever measured on Earth was -129 Fahrenheit (-89 Celsius) at Vostok, Antarctica, on July 21,
1983.
3. How much space dust falls to Earth each year?
Estimates vary, but the USGS says at least 1,000 million grams, or roughly 1,000 tons of material enters the
atmosphere every year and makes its way to Earths surface. One group of scientists claims microbes rain down from
space, too, and that extraterrestrial organisms are responsible for flu epidemics. There's been no proof of this.
4. How far does regular dust blow in the wind?
A 1999 study showed that African dust finds its way to Florida and can help push parts of the state over the prescribed
air quality limit for particulate matter set by the U.S. Environmental Protection Agency. The dust is kicked up by high
winds in North Africa and carried as high as 20,000 feet (6,100 meters), where it's caught up in the trade winds and
carried across the sea. Dust from China makes its way to North America, too.
5. What would a 100-pound person weigh on Mars?
The gravity on Mars is 38 percent of that found on Earth at sea level. So a 100-pound person on Earth would weigh 38
pounds on Mars
6. How long is the average Martian day?
A Martian can sleep (or work) and extra half-hour every day compared to you. Mars days are 24 hours and 37 minutes
long, compared to 23 hours, 56 minutes on Earth. A day on any planet in our solar system is determined by how long it
takes the world to spin once on its axis, making the Sun appear to rise in the morning and sending it down in the
evening.
7. How far is it to the center of the Earth?
The distance from the surface of Earth to the center is about 3,963 miles (6,378 kilometers). Much of Earth is fluid.
The mostly solid skin of the planet is only 41 miles (66 kilometers) thick -- thinner than the skin of an apple, relatively
speaking.
8. Has the Moon always been so close?
It used to be much closer! A billion years ago, the Moon was in a tighter orbit, taking just 20 days to go around us and
make a month. A day on Earth back then was only 18 hours long. The Moon is still moving away -- about 1.6 inches
(4 centimeters) a year. Meanwhile, Earth's rotation is slowing down, lengthening our days.
9. What is the longest river?
The Nile River in Africa is 4,160 miles (6,695 kilometers) long.
10. What's the driest place on Earth?
A place called Arica, in Chile, gets just 0.03 inches (0.76 millimeters) of rain per year.
At that rate, it would take a century to fill a coffee cup.
11. Do things inside Earth flow?
You bet. In fact, scientists found in 1999 that molten material in and around Earth's core
moves in vortices, swirling pockets whose dynamics are similar to tornadoes and hurricanes.
And as you'll learn later in this list, the planet's core moves in other strange ways, too.
12. What is the wettest place on Earth?
Lloro, Colombia averages 523.6 inches of rainfall a year, or more than 40 feet (13 meters). That's about 10 times more
than fairly wet major cities in Europe or the United States.
13. What is the largest canyon?
The Grand Canyon is billed as the world's largest canyon system. Its main branch is 277 miles (446 kilometers) long. But
let's compare. Valles Marineris on Mars extends for about 3,000 miles (4,800 kilometers). If added it to a U.S. map, it
would stretch from New York City to Los Angeles. In places this vast scar on the Martian surface is 5 miles (8
kilometers) deep.
14. Is Earth the largest rocky planet in the solar system?
Just barely! Earth's diameter at the equator is 7,926 miles (12,756 kilometers). Venus is 7,521 miles (12,104
kilometers) wide. Mercury and Mars, the other two inner rocky planets, are much smaller. Pluto is rocky, too, but it's
comparatively tiny (and some say it is not a planet at all).
15. How many of Earth’s volcanoes are known to have erupted in historic time?
About 540 volcanoes on land are known. No one knows how many undersea volcanoes have erupted through history.
16. Is air mostly oxygen?
Earth's atmosphere is actually about 80 percent nitrogen. Most of the rest is oxygen, with tiny amounts of other stuff
thrown in.
17. 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
18. 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.
19. 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).
20. 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.
21. How much surface area does Earth contain?
There are 196,950,711 square miles (510,100,000 square kilometers).
22. How hot are the planet's innards?
The temperature of Earth increases about 36 degrees Fahrenheit (20 degrees Celsius) for
every kilometer (about 0.62 miles) you go down. Near the center, its thought to be at
least 7,000 degrees Fahrenheit (3,870 Celsius).
23. Which of the following sources stores the greatest volume of fresh water
worldwide: lakes, streams or ground water?
Groundwater comprises a 30 times greater volume than all freshwater lakes, and more than 3,000 times what's in the
world’s streams and rivers at any given time. Groundwater is housed in natural underground aquifers, in which the
water typically runs around and through the stone and other material.
24. Is Earth's core solid?
The inner portion of the core is thought to be solid. But the outer portion of the core appears molten. We've never been
there though, so scientists aren't sure of the exact composition. A radical Hollywood-like idea was recently put forth to blow
a crack in the planet and send a probe down there to learn more. An interesting bit of recent evidence shows Mars'
core may be similarly squishy.
25. 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.
26. 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.. Asteroids can cause tsunami, too.
27. Are all tsunamis high waves when
they strike a coastline?
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]
28. How much of the Earth’s land surface is desert?
Asteroid-generated tsunami
About one-third.
29. 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.
30. 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).
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. 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.
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. 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.
36. 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.
37. 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.
38. Are rivers alive?
Moon making
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.
39. 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.
40. 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.
41. Is ice a mineral?
Yes, ice is a mineral and is formally described as such in Dana's System of Mineralogy.
42. 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).
43. 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.
44. On average, how much water is used worldwide each day?
About 400 billion gallons.
45. 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.
46. At what depth do most earthquakes occur?
Most are triggered less than 50 miles (80 kilometers) from the Earth’s surface. Shallower earthquakes have more
damage potential, but a temblor's destruction also depends largely on rock and soil conditions as well as building
methods.
47. 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.
48. Have there always been continents?
Breaking up
Gold rings in surprising places!
Not as we know them today. Many scientists figure Earth began as one huge continent -- dry as a bone. Water was
delivered in comets, the thinking goes, and the oceans developed. Much more recently, all the world's landmasses
were huddled into one supercontinent called Pangaea. It began to break up about 225 million years ago, eventually
fragmenting into the continents as we know them today.
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.