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Mercury

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048

Mercury

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If you ever go to Mercury, bring your sunscreen because it is the planet closest to the Sun. You'll also need a pair of thermal underwear because at night Mercury cools down fast. Temperatures can drop to as low as -292 degrees F! Now that's cold! You will also need a pair of hiking boots so you can travel and climb in and out of the craters that cover Mercury's scarred landscape.

The Strange Truth About Mercury
Mercury orbits the Sun much more quickly than Earth. Earth takes 365 days to orbit the Sun, while Mercury only takes 88! Mercury spins so slowly on its axis, that one day on Mercury lasts as long as 167 Earth days. Mercury is a tricky planet to observe with a telescope. In fact many people have never had the chance to view Mercury in the night sky because it only appears during the early morning and evening hours. Most of the time, Mercury is hidden by the Sun. Sometimes Mercury even crosses between the Sun and Earth. Because this planet moves so fast around the Sun, it was named after the Roman messenger god
-- he's so fast that he's usually shown with wings on his feet.

The best time to look at Mercury is:

in the middle of the night

when you can't see the Moon

right after sunset or just before sunrise

Are you right?

Correct!

Mercury is so close to the Sun, we can only see it when the Sun is just below the horizon. It's visible during the day, but looking for it will fry your eyes. Never look at or near the Sun without special equipment!

Frank Summers, astrophysicist

Mercury's surface shows its history of impacts back to the beginning of the solar system. Mercury lacks wind, rain, volcanoes, or other erosion that would erase the craters.

Mercury's huge metal core stretches 3/4 of the way to its surface.

Fact
or
Fiction
?

Fact

Mercury is so dense it must be mostly metal. As the solar system formed, the lightest materials were sent farthest into space.

Diameter: 3,000 miles Location: 1st planet from
Sun Average Distance from Sun: 35 million miles
Average Surface Temperature: 330 degs. F
Number of Moons: 0
Orbital Period: 88 Earth days
Characteristics: fastest orbit of any planet in solar system, atmosphere is the thinnest, and its temperatures, ranging from 180 to 450 degrees C, are the most extreme in the solar system

Image credits: courtesy of JPL, California Institute of Technology and NASA; Frank Summers: AMNH.