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100 Amazing Earth Facts |
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90. What is
the highest,
driest, and
coldest
continent on
Earth? |
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That would be Antarctica. |
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91. At what
depth do most
earthquakes
occur? |
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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. |
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92. Where are
the oldest rocks
on Earth found? |
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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. |
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93. What
percentage of
the world's
fresh water is
stored as
glacial ice? |
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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. |
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94. What is
the largest
alpine lake in
North America? |
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Lake Tahoe on the
California-Nevada border has
a 105,000-acre surface,
holds 39 trillion gallons of
water, and is almost 1,600
feet (488 meters) deep. |
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95. Have
there always
been continents? |
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 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. |
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96. How much
volcanic ash can
fall in a day? |
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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. |
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97. What is
feldspar? |
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A better question might be,
"Who but a geologists could
love feldspar?" It happens
to be the most common
mineral in Earth's crust.
But I couldn't find anything
about it that most of us
really need to know. |
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98. What are
the most extreme
locations in the
United States,
compass-wise? |
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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. |
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99.
If you were to
arrange Earth,
the Moon and
Mars like
Matryoshka
nesting dolls,
how would they
be ordered? |
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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. |
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100.
Will Earth
always be here? |
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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. |
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