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Earth is about 4.54 billion years old
Radiometric dating places Earth's age at approximately 4.54 billion years.
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Science facts, with the why included.
Everyday phenomena explained with evidence, scale, and a little wonder. Each claim includes context and a source you can inspect.
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A cloud can weigh around a million pounds
A typical fair-weather cumulus cloud can contain roughly 1.1 million pounds of water.
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Bananas are slightly radioactive
Bananas contain a tiny amount of naturally radioactive potassium-40 along with ordinary potassium.
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Saturn is less dense than water
Saturn's average density is lower than the density of liquid water.
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Rainbows are full circles
A rainbow forms as a complete circle around the point opposite the Sun, although the ground usually hides its lower portion.
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Lightning is hotter than the Sun's surface
Lightning can heat the air it passes through to 50,000 degrees Fahrenheit, five times hotter than the surface of the Sun.
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The adult human body is up to 60 percent water
Up to 60 percent of the adult human body is water.
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The ocean is blue because water absorbs red light
The ocean is blue because water absorbs colors in the red part of the light spectrum and leaves the blue.
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A second is defined by cesium atoms
Atomic clocks count 9,192,631,770 microwave oscillations of cesium atoms and call that interval one second.
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Tectonic plates move as fast as fingernails grow
Earth's tectonic plates move at roughly the same rate that your fingernails grow.
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A nautical mile is one minute of latitude
One nautical mile equals one minute of latitude, or about 1.15 land miles.
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The ocean holds 97 percent of Earth's water
About 97 percent of all the water on Earth is in the ocean.
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The strongest recorded earthquake was magnitude 9.5
The largest earthquake recorded since 1900 struck Chile on May 22, 1960, at magnitude 9.5.
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Some beach sand is parrotfish poop
Parrotfish grind up coral reef material in their guts and excrete it as sand.
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Ocean pressure rises with every 33 feet of depth
For every 33 feet you go down in the ocean, the pressure increases by one atmosphere.
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Petrified wood is almost solid quartz
The petrified wood of Petrified Forest National Park is made up of almost solid quartz.
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The sea is salty because rain wears down rocks
Rocks on land are the major source of the salts dissolved in seawater.
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Seawater contains gold
One study found about one gram of gold in every 100 million metric tons of ocean water.
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Coast redwoods can grow 367 feet tall
California's coast redwoods may grow to 367 feet, about the height of a 35-story skyscraper.
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About half of Earth's oxygen comes from the ocean
About half of Earth's oxygen comes from the ocean.
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Earth is not a perfect sphere
Earth bulges at the equator because of the centrifugal force created by its constant rotation.
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Hurricanes and typhoons are the same kind of storm
The only difference between a hurricane and a typhoon is the place where the storm occurs.
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Most ocean species have not been classified
Scientists estimate that 91 percent of the species in the ocean have yet to be classified.
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Any two people share about 99.6% of their DNA
On average, any two people's genomes are about 99.6 percent identical.
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Rogue waves are twice as big as the waves around them
Scientists define rogue waves as waves greater than twice the size of the waves around them.
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GPS satellites circle Earth twice a day
GPS satellites fly at an altitude of about 20,200 kilometers, and each one circles Earth twice a day.
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Seawater freezes at about 28 degrees Fahrenheit
Fresh water freezes at 32 degrees Fahrenheit, but seawater freezes at about 28.4 degrees because of the salt in it.
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Large hailstones fall at up to 72 mph
Hailstones 2 to 4 inches wide are expected to fall at between 44 and 72 miles per hour.
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Deep-sea vents top 700 degrees without boiling
Seawater in hydrothermal vents can reach over 700 degrees Fahrenheit, yet it does not boil because of the extreme pressure.
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The largest tree on Earth is a giant sequoia
The General Sherman Tree is the largest tree in the world by volume, at an estimated 52,500 cubic feet.
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Kelp can grow 18 inches in a day
In ideal conditions, kelp can grow up to 18 inches per day.
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Sunlight barely reaches below 200 meters in the sea
There is rarely any significant light deeper than 200 meters in the ocean, and sunlight does not reach below 1,000 meters.
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A tsunami can cross the ocean as fast as a jet
Over deep water, tsunami waves may travel as fast as jet planes, slowing only when they reach the shallows.
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