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A day on Venus is longer than its year
Venus takes about 243 Earth days to rotate once but only about 225 Earth days to orbit the Sun.
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Space facts, with the why included.
Planets, moons, and the surprising mechanics of our solar system. Each claim includes context and a source you can inspect.
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The space station sees about 16 sunrises a day
The International Space Station circles Earth roughly every 90 minutes, giving its crew about 16 sunrises and sunsets in 24 hours.
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Sunsets on Mars can appear blue
Near the setting Sun, fine dust in the Martian atmosphere can produce a blue glow instead of the red sunset familiar on Earth.
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Uranus rotates on its side
Uranus has an axial tilt of about 98 degrees, so the planet appears to roll around the Sun on its side.
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Triton orbits Neptune backward
Neptune's largest moon, Triton, travels around the planet in the direction opposite Neptune's rotation.
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The Moon is drifting away from Earth
The Moon moves about an inch farther from Earth every year.
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Saturn's north pole has a hexagon
A six-sided jet stream circles Saturn's north pole in the shape of a hexagon.
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Hubble circles Earth every 95 minutes
The Hubble Space Telescope orbits at about 17,000 miles per hour and circles Earth once every 95 minutes.
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1.3 million Earths could fit inside the Sun
It would take 1.3 million Earths to fill the Sun's volume.
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The Sun holds 99.8% of the solar system's mass
The Sun accounts for 99.8 percent of all the mass in the solar system.
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Ceres is the largest object in the asteroid belt
The dwarf planet Ceres is the largest object in the asteroid belt between Mars and Jupiter.
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Jupiter's Great Red Spot is bigger than Earth
The Great Red Spot is a giant storm on Jupiter that is bigger than Earth and has raged for hundreds of years.
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Voyager carries greetings in 55 languages
The Voyager Golden Record holds spoken greetings in 55 languages and 115 images.
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About 48 tons of space rock fall on Earth daily
Scientists estimate that about 48.5 tons of meteoritic material falls on Earth each day.
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A year on Neptune lasts 165 Earth years
Neptune takes about 165 Earth years to complete one orbit of the Sun.
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Neptune was found with mathematics
Neptune was the first planet located through mathematical predictions rather than by regular observation of the sky.
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Venus is hotter than Mercury
Venus is the hottest planet in the solar system, even though Mercury is closer to the Sun.
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Mars is red because it is rusty
Mars looks red because iron minerals in its dirt oxidize, or rust.
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Uranus was the first planet found by telescope
Uranus was the first planet found with the aid of a telescope, by William Herschel in 1781.
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Jupiter has rings too
Jupiter has rings, discovered in 1979 by NASA's Voyager 1 spacecraft.
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Voyager 1 is the farthest spacecraft from Earth
No spacecraft has gone farther than Voyager 1, which crossed into interstellar space in August 2012.
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Titan is the only moon with a thick atmosphere
Saturn's moon Titan is the only moon in the solar system known to have a substantial atmosphere.
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All asteroids together weigh less than the Moon
The total mass of all the asteroids combined is less than that of Earth's Moon.
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Jupiter has the shortest day of any planet
Jupiter spins once in about 9.9 hours, the shortest day in the solar system.
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Mars has the largest volcano in the solar system
Olympus Mons on Mars is the largest volcano in the solar system, with a base as large as the state of Arizona.
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Mercury is the fastest planet
Mercury zips around the Sun every 88 Earth days, faster than any other planet.
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Earth is the only planet not named for a god
Every planet except Earth was named after a Greek or Roman god or goddess.
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Mars is slowly pulling its moon Phobos in
Phobos draws about six feet closer to Mars every hundred years.
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Parker Solar Probe flies at 430,000 mph
At its closest approach to the Sun, Parker Solar Probe travels at about 430,000 miles per hour.
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A canyon on Mars would span the United States
Valles Marineris on Mars is long enough to stretch from California to New York.
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Comets have two tails
A comet has two tails, one of dust and one of ionized gas.
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Pluto is about half as wide as the United States
Pluto is only about 1,400 miles wide, roughly half the width of the United States.
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A light-year is about 6 trillion miles
A light-year is the distance light travels in one Earth year, about 6 trillion miles.
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