True or False Space Facts
Explore true or false facts about planets, moons, stars and spaceflight. Read a statement, then open its answer and explanation
On Venus the Sun would rise in the west and set in the east
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TrueVenus spins backward compared with most planets, and very slowly, so its Sun crosses the sky the wrong way
Source: science.nasa.gov
Pluto is only about 70% as wide as Earth's Moon
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TruePluto measures around 2,380 km across and the Moon 3,470 km, and Pluto has less than 20% of the Moon's mass
Source: science.nasa.gov
The far side of the Moon never gets sunlight, so it is called the dark side
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FalseBoth sides of the Moon get about two weeks of sunlight in turn; we just never see the far side from Earth
Source: science.nasa.gov
A typical shooting star is caused by a rock about the size of a football
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FalseMost are made by specks between a grain of sand and a pea, which burn up high in the atmosphere
Source: science.nasa.gov
If the Sun turned into a black hole of the same mass, Earth would be sucked in
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FalseGravity at Earth's distance would stay the same, so Earth would keep orbiting, only in darkness and cold
Source: science.nasa.gov
Astronauts become taller in space because their spines stretch without gravity
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TrueWith no gravity pressing it down, the spine lengthens and height can grow by as much as 3% until they return to Earth
Source: nasa.gov
Jupiter is almost massive enough to have become a star
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FalseIt would need about 80 times more mass to start fusion like a star, so Jupiter is nowhere near the limit
Source: nasa.gov
Saturn is so light for its size that it is less dense than water
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TrueSaturn is mostly hydrogen and helium, so its average density is below that of water, unlike every other planet
Source: science.nasa.gov
The Moon is drifting away from Earth by a few centimeters every year
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TrueLaser beams bounced off mirrors that Apollo crews left on the Moon show its distance growing by about 3.8 cm a year
Source: eclipse.gsfc.nasa.gov
The Sun is about 400 times wider than the Moon and about 400 times farther away
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TrueThat near-perfect match makes both look the same size in the sky, which makes total solar eclipses possible
Source: science.nasa.gov
The Sun's outer atmosphere, the corona, is cooler than its visible surface
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FalseThe corona reaches up to about 2 million degrees Celsius, far hotter than the roughly 5,500 degrees of the visible surface
Source: science.nasa.gov
Earth is closest to the Sun in the middle of the northern summer
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FalseEarth is closest in early January and farthest in July; the tilt of its axis, not distance, causes the seasons
Source: spaceplace.nasa.gov
The Andromeda galaxy is visible without a telescope under dark skies
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TrueAndromeda is about 2.5 million light-years away, yet it shows as a faint misty patch to the unaided eye
Source: science.nasa.gov
Laika, a Soviet dog, was the first animal ever sent into space, in 1957
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FalseMonkeys had flown to space on rockets years earlier; Laika was the first animal to orbit Earth
Source: nasa.gov
Sunsets on Mars look red, just like sunsets on Earth
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FalseMartian dust lets blue light pass through more easily than red, so the sky around the setting Sun looks blue
Source: svs.gsfc.nasa.gov
Uranus's upper atmosphere holds the gas that gives rotten eggs their smell
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TrueAstronomers detected hydrogen sulfide, the gas behind that smell, just above the main cloud layer of Uranus
Source: nature.com
Neptune's biggest moon Triton orbits in the same direction as the planet spins
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FalseTriton is the only large moon that circles its planet backward, a hint that Neptune captured it from the Kuiper Belt
Source: science.nasa.gov
The Moon is slowly shrinking as its interior cools, wrinkling its crust
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TrueIn several hundred million years it has grown about 50 meters narrower, and its cracking crust may still cause moonquakes
Source: nasa.gov
A spacecraft heats up on re-entry mainly because of friction with the air
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FalseThe air ahead of it is squeezed so fast that it heats to thousands of degrees; friction plays a smaller part
Source: nasa.gov
After a spacewalk, astronauts say their suits smell like seared steak and welding fumes
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TrueCrew members describe a strong metallic smell clinging to their suits, helmets, gloves and tools once they are back inside
Source: nasa.gov