Pluto :
Cloze Activity Answers
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Word Bank :
Tombaugh
farthest
dot
moon
spacecraft |
mass
gravity
8
1978
ninth |
direction
Sun
orbit
Pluto
asteroid |
Pluto is the ninth and usually the farthest planet from the Sun in our Solar System; it is also the smallest planet in our Solar System. This cold, rocky planet was the last planet to be discovered. Clyde W. Tombaugh discovered Pluto in 1930. Pluto is the only planet in our Solar System that has not been visited by our spacecraft yet. We only have blurry pictures of its surface. From Pluto, the Sun would look like a tiny dot in the sky.
Pluto is about 1,413 miles (2274 km) in diameter. This is about 1/5 the diameter of the Earth. It is smaller than a lot of the other planets' moons, including our moon .
Pluto's mass is about 1.29 x 10 22 kg; it is the least massive planet in our Solar System. Pluto is about 1/500th of the mass of the Earth. The gravity on Pluto is only 8% of the gravity on Earth. A 100 pound person on Pluto would weigh only 8 pounds.
Each day on Pluto takes 6.39 Earth days. Each year on Pluto takes 247.7 Earth years (that is, it takes 247.7 Earth years for Pluto to orbit the Sun once).
Pluto has a very eccentric orbit ; that means that its distance from the sun varies a lot during its orbit around the sun. Pluto also rotates about its axis in the opposite direction from most of the other planets. Pluto's orbit is tilted from the plane of the ecliptic. This angle, its orbital inclination, is 17.15°. This is the largest inclination of any of the planets. Pluto's unusual orbit makes some scientists think that Pluto is not a regular planet, but perhaps an asteroid .
Pluto has one moon, Charon, that is almost as big as Pluto itself. Charon was discovered by Jim Christy in 1978 . Charon was named after the mythological demon who ferried people across the mythological river Styx into Hades.
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