Space222 sourced facts
Space facts
Surprising space facts that are actually true. Tap any card for the details and the source, then download or share it.
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SpaceSpace facts: all 222, explained
A day on Venus is longer than a year on Venus.
Venus takes about 243 Earth days to spin once on its axis, but only about 225 Earth days to orbit the Sun. It also spins backwards compared with most planets, so on Venus the Sun would rise in the west.
Source: Venus (Wikipedia) · Fact card
Astronauts’ footprints on the Moon could last for millions of years.
The Moon has almost no atmosphere, so there is no wind or rain to wear footprints away. The main threat is the slow rain of tiny meteorites, which takes a very long time to erase them.
Source: Moon (Wikipedia) · Fact card
A teaspoon of neutron star would weigh about a billion tonnes on Earth.
Neutron stars are the collapsed cores of massive stars, packing more mass than the Sun into a ball roughly 20 kilometres across. Their matter is so dense that a sugar-cube-sized piece would weigh as much as a mountain.
Source: Neutron star (Wikipedia) · Fact card
Sunlight takes about 8 minutes to reach Earth.
The Sun is about 150 million kilometres away, and light travels at about 300,000 kilometres per second, so the sunlight you see left the Sun about 8 minutes and 20 seconds ago.
Source: Sunlight (Wikipedia) · Fact card
Saturn is less dense than water.
Saturn is mostly hydrogen and helium, and its average density is lower than that of water. In theory, if you had a bathtub big enough, Saturn would float, although it would not survive the experience.
Source: Saturn (Wikipedia) · Fact card
Mars has a volcano about two and a half times as tall as Mount Everest.
Olympus Mons on Mars rises about 22 kilometres above the surrounding plains, and its base is roughly the size of the state of Arizona. It is one of the largest volcanoes in the Solar System.
Source: Olympus Mons (Wikipedia) · Fact card
Space is completely silent.
Sound needs a medium like air or water to travel through. In the near-vacuum of space, there are too few particles to carry sound waves, so explosions and engines make no sound outside a spacecraft.
Source: Sound (Wikipedia) · Fact card
Astronauts on the International Space Station see about 16 sunrises a day.
The ISS orbits Earth roughly every 90 minutes at about 28,000 km/h, so it passes from day to night around 16 times every 24 hours.
Jupiter’s Great Red Spot is a storm bigger than Earth.
The Great Red Spot is a giant storm in Jupiter’s atmosphere that has been observed for well over 150 years. It has been shrinking, but it is still wider than our planet.
Source: Great Red Spot (Wikipedia) · Fact card
About 1.3 million Earths could fit inside the Sun.
The Sun’s diameter is about 109 times Earth’s, so its volume is roughly 1.3 million times larger. Even so, the Sun is an average-sized star.
Source: Sun (Wikipedia) · Fact card
Uranus spins on its side.
Uranus is tilted by about 98 degrees, so it rolls around the Sun like a ball. Each pole gets about 42 years of continuous sunlight followed by 42 years of darkness. A giant collision long ago is the leading explanation.
Source: Uranus (Wikipedia) · Fact card
The first animal to orbit Earth was a dog called Laika.
Laika, a stray from the streets of Moscow, was launched aboard the Soviet Sputnik 2 in November 1957. She did not survive the flight, but her mission showed that a living creature could survive launch and weightlessness, paving the way for human spaceflight.
Source: Laika (Wikipedia) · Fact card
Mars is red because it’s covered in rust.
The dust and rocks on Mars contain a lot of iron oxide, the same compound as rust. Fine red dust blown into the air gives the sky an orange-pink tint too.
Source: Mars (Wikipedia) · Fact card
Sunsets on Mars are blue.
Fine Martian dust scatters blue light forward, near the direction of the Sun. As the Sun sets, the sky around it glows blue, the reverse of Earth.
Source: Mars (Wikipedia) · Fact card
Mars has two small, potato-shaped moons named Fear and Dread.
Phobos and Deimos are named after the sons of Ares, the Greek god of war, and mean fear and dread. Phobos is slowly spiralling closer to Mars and will eventually break apart or crash into it.
Source: Moons of Mars (Wikipedia) · Fact card
A day on Mars is only about 40 minutes longer than a day on Earth.
One Martian day, called a sol, lasts about 24 hours and 40 minutes. A Martian year, though, is 687 Earth days.
Source: Mars (Wikipedia) · Fact card
Saturn’s rings are huge but in many places only about 10 metres thick.
The main rings stretch hundreds of thousands of kilometres across but are extremely thin. They are made mostly of chunks of water ice, from tiny grains to pieces the size of a house.
Source: Rings of Saturn (Wikipedia) · Fact card
Saturn has more known moons than any other planet: over 270.
Astronomers keep finding small moons around Saturn, and its count passed 270 in 2025. The largest, Titan, is bigger than the planet Mercury and has lakes of liquid methane.
Source: Moons of Saturn (Wikipedia) · Fact card
Jupiter spins so fast that a day there lasts less than 10 hours.
Jupiter is the biggest planet in the solar system, yet it completes one rotation in about 9 hours and 56 minutes, the shortest day of any planet. The fast spin makes it bulge at the equator.
Source: Jupiter (Wikipedia) · Fact card
Jupiter’s moon Ganymede is bigger than the planet Mercury.
Ganymede is the largest moon in the solar system. It is the only moon known to have its own magnetic field and is thought to hide a salty ocean under its icy crust.
Source: Ganymede (moon) (Wikipedia) · Fact card
Jupiter is more than twice as massive as all the other planets combined.
Jupiter’s mass is about 318 times that of Earth and roughly two and a half times the mass of all the other planets in the solar system put together.
Source: Jupiter (Wikipedia) · Fact card
Neptune has the fastest winds in the solar system.
Winds on Neptune have been measured at around 2,000 km/h, faster than the speed of sound on Earth, even though the planet is far from the Sun’s heat.
Source: Neptune (Wikipedia) · Fact card
Neptune was found by maths before anyone saw it.
Astronomers noticed Uranus was being tugged off course and calculated where an unseen planet must be. In 1846, Johann Galle pointed a telescope at the predicted spot and found Neptune.
Source: Neptune (Wikipedia) · Fact card
Neptune completed its first full orbit since its discovery only in 2011.
Neptune takes about 165 Earth years to go around the Sun. It was discovered in 1846, so it did not return to the same spot until 2011.
Source: Neptune (Wikipedia) · Fact card
Venus is the hottest planet, even though Mercury is closer to the Sun.
Venus’s thick carbon dioxide atmosphere traps heat, keeping the surface at around 465 °C, hot enough to melt lead. Mercury has almost no atmosphere, so its heat escapes.
Source: Venus (Wikipedia) · Fact card
After the Moon, Venus is the brightest natural object in the night sky.
Venus is bright because it is close and covered in reflective clouds. It is often called the morning or evening star because it shines near sunrise or sunset.
Source: Venus (Wikipedia) · Fact card
Mercury and Venus are the only planets with no moons.
Every other planet in the solar system has at least one moon. Mercury is also the smallest planet and the closest to the Sun.
Source: Mercury (planet) (Wikipedia) · Fact card
On Mercury, temperatures swing from about 430 °C in the day to about minus 180 °C at night.
Mercury has almost no atmosphere to hold heat, so the sunlit side bakes and the night side freezes. A year on Mercury is only 88 Earth days.
Source: Mercury (planet) (Wikipedia) · Fact card
Uranus was the first planet discovered with a telescope.
William Herschel spotted Uranus in 1781, at first thinking it was a comet. All the planets closer to the Sun were known since ancient times because they are visible to the naked eye.
Source: Uranus (Wikipedia) · Fact card
Earth isn’t a perfect sphere. It bulges at the equator.
Earth’s spin flattens it slightly, so the distance through the equator is about 43 km more than from pole to pole. Because of the bulge, the peak of Chimborazo in Ecuador is the point farthest from Earth’s center.
Source: Earth (Wikipedia) · Fact card
Days on Earth are slowly getting longer.
The Moon’s pull on the oceans acts like a brake on Earth’s spin. Over time this adds a tiny fraction of a second to the length of a day, so in the age of the dinosaurs a day was shorter than 24 hours.
Source: Tidal acceleration (Wikipedia) · Fact card
The Sun makes up more than 99.8% of the mass of the solar system.
All the planets, moons, asteroids and comets together are a tiny fraction of the solar system’s mass. Jupiter accounts for most of what is left.
Source: Sun (Wikipedia) · Fact card
The Moon is drifting away from Earth by about 3.8 cm a year.
Laser measurements using reflectors left by Apollo astronauts show the Moon moves away from Earth by about 3.8 centimetres a year, roughly as fast as fingernails grow.
Source: Lunar Laser Ranging experiments (Wikipedia) · Fact card
We always see the same side of the Moon.
The Moon spins once on its axis in the same time it takes to orbit Earth, so the same face always points towards us. This is called tidal locking. The far side was first photographed by a Soviet probe in 1959.
Source: Tidal locking (Wikipedia) · Fact card
Pluto has a giant heart-shaped plain on its surface.
When NASA’s New Horizons probe flew past Pluto in 2015, it photographed a bright heart-shaped region, now called Tombaugh Regio after Pluto’s discoverer, Clyde Tombaugh.
Source: Pluto (Wikipedia) · Fact card
Pluto was a planet for 76 years.
Pluto was discovered in 1930 and counted as the ninth planet until 2006, when the International Astronomical Union reclassified it as a dwarf planet after similar objects were found beyond Neptune.
Source: Pluto (Wikipedia) · Fact card
The International Space Station circles Earth about every 90 minutes.
The ISS travels at about 28,000 km/h, roughly 7.7 km every second, completing about 15 or 16 orbits a day. You can often see it from the ground as a bright, fast-moving dot.
A year on Mars lasts 687 Earth days.
Mars is farther from the Sun than Earth, so it takes almost twice as long to complete an orbit.
Source: Mars (Wikipedia) · Fact card
Mars has a canyon system that would stretch across the United States.
Valles Marineris is about 4,000 kilometers long and up to 7 kilometers deep, making the Grand Canyon look small.
Source: Valles Marineris (Wikipedia) · Fact card
The air on Mars is about 100 times thinner than Earth’s.
The Martian atmosphere is mostly carbon dioxide, and its pressure at the surface is less than 1% of Earth’s, so liquid water would quickly boil or freeze.
Source: Atmosphere of Mars (Wikipedia) · Fact card
You would weigh only about 38% as much on Mars.
Mars is smaller and less massive than Earth, so its surface gravity is about 0.38 of ours. A 100-pound child would weigh about 38 pounds there.
Source: Mars (Wikipedia) · Fact card
Mars has ice caps at both poles.
The polar caps are made of water ice with a seasonal layer of frozen carbon dioxide that grows in winter and shrinks in summer.
Source: Martian polar ice caps (Wikipedia) · Fact card
Dust storms on Mars can cover the whole planet.
Global dust storms can last for weeks or months. One in 2018 blocked so much sunlight that NASA’s solar-powered Opportunity rover lost power and never woke up.
Source: Opportunity (rover) (Wikipedia) · Fact card
A small helicopter made the first powered flight on another planet, on Mars in 2021.
NASA’s Ingenuity helicopter flew on Mars on 19 April 2021 and went on to make 72 flights, far more than the five originally planned.
Source: Ingenuity (helicopter) (Wikipedia) · Fact card
Mars is the only planet known to be inhabited entirely by robots.
Rovers, landers and orbiters from several countries have explored Mars since the 1970s, including NASA’s Curiosity and Perseverance rovers and China’s Zhurong.
Source: Exploration of Mars (Wikipedia) · Fact card
Twelve people have walked on the Moon, all between 1969 and 1972.
Every Moon walker was an American astronaut on one of six Apollo landings. The first was Neil Armstrong in July 1969 and the last was Gene Cernan in December 1972.
The Moon has earthquakes, called moonquakes.
Seismometers left by Apollo astronauts recorded moonquakes, some caused by Earth’s pull and others by the Moon’s surface heating and cooling.
Source: Moonquake (Wikipedia) · Fact card
The Moon’s gravity causes most of the ocean tides.
The Moon pulls on Earth’s oceans, creating bulges of water that move around the planet as Earth turns. The Sun adds a smaller pull.
Source: Tide (Wikipedia) · Fact card
The Moon probably formed when a planet-sized object hit the early Earth.
The leading theory is that a Mars-sized body, often called Theia, struck Earth about 4.5 billion years ago and the debris came together to form the Moon.
Source: Giant-impact hypothesis (Wikipedia) · Fact card
There are golf balls on the Moon.
Apollo 14 astronaut Alan Shepard hit two golf balls on the lunar surface in 1971 using a club head attached to a sample-collecting tool.
Source: Alan Shepard (Wikipedia) · Fact card
Gravity on the Moon is about one sixth of Earth’s.
That is why astronauts bounced along in big hops. You could jump about six times higher on the Moon than at home.
Source: Moon (Wikipedia) · Fact card
The "dark side of the Moon" is not actually dark.
The far side gets as much sunlight as the near side. It is only hidden from Earth, not from the Sun.
Source: Far side of the Moon (Wikipedia) · Fact card
Temperatures on the Moon swing by nearly 300°C between day and night.
With no air to hold heat, the surface can reach over 120°C in sunlight and drop below minus 170°C in darkness.
Source: Moon (Wikipedia) · Fact card
Mars is about half as wide as Earth.
Its diameter is about 6,779 kilometers, roughly 53% of Earth’s, but its land area is about the same as all of Earth’s dry land.
Source: Mars (Wikipedia) · Fact card
Mars is the fourth planet from the Sun.
It orbits at an average distance of about 228 million kilometers, about one and a half times as far as Earth.
Source: Mars (Wikipedia) · Fact card
Mars is named after the Roman god of war.
Its blood-red color reminded ancient observers of war. Its moons Phobos and Deimos are named after the sons of the Greek war god Ares.
Source: Mars in culture (Wikipedia) · Fact card
Mars has seasons, like Earth.
Its axis is tilted about 25 degrees, close to Earth’s 23.4, so it has seasons, but each lasts roughly twice as long.
Source: Mars (Wikipedia) · Fact card
Mars is very cold: around minus 60°C on average.
Temperatures can reach about 20°C at the equator on a summer afternoon and fall below minus 120°C at the poles.
Source: Climate of Mars (Wikipedia) · Fact card
Mars once had rivers and lakes.
Dried riverbeds, deltas and minerals that form in water show that liquid water flowed on Mars billions of years ago.
Source: Water on Mars (Wikipedia) · Fact card
The first successful landing on Mars was in 1976.
NASA’s Viking 1 lander touched down in July 1976 and sent back the first photos from the Martian surface.
Source: Viking 1 (Wikipedia) · Fact card
A NASA rover has been collecting rock samples on Mars to bring back to Earth.
Perseverance, which landed in Jezero Crater in 2021, seals rock cores in tubes for a future sample-return mission.
Source: Perseverance (rover) (Wikipedia) · Fact card
Pieces of Mars have landed on Earth.
More than 300 meteorites found on Earth have been identified as Martian, blasted off Mars by asteroid impacts.
Source: Martian meteorite (Wikipedia) · Fact card
Mars comes closest to Earth about every 26 months.
At these oppositions Mars can come within about 56 million kilometers, which is when space agencies usually launch missions.
Source: Mars (Wikipedia) · Fact card
The daytime sky on Mars is a butterscotch color.
Fine dust in the air scatters light, giving the Martian sky a pinkish-tan color by day.
Source: Atmosphere of Mars (Wikipedia) · Fact card
Mars has a huge volcanic region called Tharsis.
Tharsis is home to four giant volcanoes, including Olympus Mons, and is so massive it may have shifted the planet’s tilt.
Source: Tharsis (Wikipedia) · Fact card
You could jump almost three times as high on Mars.
With gravity only about 38% of Earth’s, the same jump would take you nearly three times higher.
Source: Gravity of Mars (Wikipedia) · Fact card
Sunlight on Mars is less than half as strong as on Earth.
Because Mars is farther from the Sun, the light reaching it is about 43% as intense, which matters for solar-powered rovers.
Source: Mars (Wikipedia) · Fact card
From Mars, Earth looks like a bright evening or morning star.
Rovers have photographed Earth as a small bright dot in the Martian sky.
Source: Earth from Mars (Wikipedia) · Fact card
Mars has one of the biggest impact craters in the solar system.
Hellas Planitia is about 2,300 kilometers across and about 7 kilometers deep.
Source: Hellas Planitia (Wikipedia) · Fact card
Scientists have detected puzzling traces of methane on Mars.
NASA’s Curiosity rover measured small, changing amounts of methane, a gas that on Earth is often made by living things, though it can also come from geology.
Source: Atmosphere of Mars (Wikipedia) · Fact card
Mars lost its global magnetic field long ago.
Without a magnetic shield, the solar wind gradually stripped away much of Mars’s atmosphere.
Source: Mars (Wikipedia) · Fact card
The Moon is the fifth-largest moon in the solar system.
It is about a quarter as wide as Earth, which makes it unusually large compared with its planet.
Source: Moon (Wikipedia) · Fact card
The Moon is about 384,400 kilometers away.
All the other planets in the solar system could fit in the gap between Earth and the Moon.
Source: Lunar distance (Wikipedia) · Fact card
Moonlight takes about 1.3 seconds to reach Earth.
That small delay was noticeable in radio conversations with Apollo astronauts.
Source: Lunar distance (Wikipedia) · Fact card
The Moon has almost no atmosphere.
Without air to scatter light, the sky on the Moon is black even in daytime, and there is no wind or weather.
Source: Atmosphere of the Moon (Wikipedia) · Fact card
There is water ice on the Moon.
Ice has been found in permanently shadowed craters near the poles, which is why future bases are planned there.
Source: Lunar water (Wikipedia) · Fact card
The Moon goes through its phases every 29.5 days.
The phases happen because we see different amounts of the Moon’s sunlit half as it orbits Earth.
Source: Lunar phase (Wikipedia) · Fact card
The word "month" comes from the Moon.
Many early calendars were based on the cycle of lunar phases.
Source: Month (Wikipedia) · Fact card
A "blue moon" is usually the second full moon in a calendar month.
It happens about every two to three years. The Moon does not actually turn blue.
Source: Blue moon (Wikipedia) · Fact card
During a total lunar eclipse, the Moon turns red.
Sunlight bent through Earth’s atmosphere reaches the Moon, giving it a coppery color sometimes called a blood moon.
Source: Lunar eclipse (Wikipedia) · Fact card
The dark patches on the Moon are ancient lava plains.
Early astronomers thought they were seas and called them maria, Latin for "seas".
Source: Lunar mare (Wikipedia) · Fact card
The American flags left on the Moon have probably been bleached white.
Decades of strong sunlight without an atmosphere are thought to have faded the colors.
Source: Lunar Flag Assembly (Wikipedia) · Fact card
Astronauts drove cars on the Moon.
The Lunar Roving Vehicle was used on Apollo 15, 16 and 17, and all three are still there.
Source: Lunar Roving Vehicle (Wikipedia) · Fact card
China made the first landing on the Moon’s far side in 2019.
The Chang’e 4 mission landed in the Von Kármán crater and deployed a rover.
Source: Chang’e 4 (Wikipedia) · Fact card
Apollo astronauts brought back 382 kilograms of Moon rock.
Samples are still studied today and some are loaned to schools and museums.
Source: Moon rock (Wikipedia) · Fact card
A supermoon looks bigger because the Moon is closer.
The Moon’s orbit is an oval, so a full moon near its closest point can look up to about 14% larger than one at its farthest.
Source: Supermoon (Wikipedia) · Fact card
NASA plans to send astronauts back to the Moon under the Artemis program.
Artemis aims to land people near the Moon’s south pole, the first crewed landings since 1972.
Source: Artemis program (Wikipedia) · Fact card
The Moon "rang like a bell" when a rocket stage hit it.
Apollo seismometers recorded vibrations lasting over an hour after spent rocket stages crashed into the surface.
Source: Moonquake (Wikipedia) · Fact card
Jupiter is the fifth planet from the Sun and the largest.
It is about 11 times as wide as Earth, and more than 1,300 Earths could fit inside it.
Source: Jupiter (Wikipedia) · Fact card
Jupiter has no solid surface.
It is a gas giant made mostly of hydrogen and helium, getting denser and hotter toward a possible rocky core.
Source: Jupiter (Wikipedia) · Fact card
Jupiter has around 95 known moons.
The count keeps rising as telescopes find small, distant moons.
Source: Moons of Jupiter (Wikipedia) · Fact card
Galileo discovered Jupiter’s four biggest moons in 1610.
Io, Europa, Ganymede and Callisto are called the Galilean moons. Seeing them orbit Jupiter helped show that not everything circles Earth.
Source: Galilean moons (Wikipedia) · Fact card
Jupiter’s moon Io is the most volcanic place in the solar system.
Tidal squeezing from Jupiter heats Io’s interior, powering hundreds of active volcanoes.
Source: Io (moon) (Wikipedia) · Fact card
Jupiter’s moon Europa probably hides an ocean under its ice.
Scientists think the ocean holds more water than all of Earth’s oceans, making Europa a target in the search for life.
Source: Europa (moon) (Wikipedia) · Fact card
Jupiter has faint rings.
They are made of dust and were discovered by the Voyager 1 probe in 1979.
Source: Rings of Jupiter (Wikipedia) · Fact card
A year on Jupiter lasts about 12 Earth years.
Jupiter orbits the Sun at an average of about 778 million kilometers.
Source: Jupiter (Wikipedia) · Fact card
Jupiter has the strongest magnetic field of any planet.
It is about 20,000 times stronger than Earth’s and traps intense radiation belts around the planet.
Jupiter has auroras bigger than Earth.
They glow at the poles in ultraviolet light and are powered partly by material from the moon Io.
Source: Jupiter (Wikipedia) · Fact card
NASA’s Juno spacecraft has orbited Jupiter since 2016.
Juno studies the planet’s interior, gravity and magnetic field from a polar orbit.
Source: Juno (spacecraft) (Wikipedia) · Fact card
A comet smashed into Jupiter in 1994.
Fragments of Comet Shoemaker-Levy 9 hit Jupiter over several days, leaving dark scars larger than Earth.
Source: Comet Shoemaker-Levy 9 (Wikipedia) · Fact card
Jupiter’s gravity may protect Earth from some comets.
Its huge gravity pulls in or flings away many objects, though scientists still debate how much it shields Earth.
Source: Jupiter (Wikipedia) · Fact card
Jupiter is often the fourth-brightest object in the night sky.
Only the Moon and Venus are usually brighter, and sometimes Mars at close approach.
Source: Jupiter (Wikipedia) · Fact card
Jupiter is named after the king of the Roman gods.
Many of its moons are named after figures from myths about Jupiter, or Zeus in Greek myth.
Source: Jupiter (mythology) (Wikipedia) · Fact card
Jupiter’s stripes are bands of clouds moving in opposite directions.
Light zones and dark belts are separated by powerful jet streams.
Source: Atmosphere of Jupiter (Wikipedia) · Fact card
Jupiter’s top clouds are made of ammonia ice.
Lower layers are thought to contain ammonium hydrosulfide and water clouds.
Source: Atmosphere of Jupiter (Wikipedia) · Fact card
The Great Red Spot is shrinking.
It was about three Earths wide in the late 1800s and is now a little wider than one Earth.
Source: Great Red Spot (Wikipedia) · Fact card
Ganymede is the only moon known to have its own magnetic field.
It probably comes from a molten iron core inside the moon.
Source: Ganymede (moon) (Wikipedia) · Fact card
Callisto is one of the most heavily cratered objects in the solar system.
Its ancient surface has barely changed for billions of years.
Source: Callisto (moon) (Wikipedia) · Fact card
The first spacecraft to fly past Jupiter was Pioneer 10, in 1973.
It sent back the first close-up images of the planet.
Source: Pioneer 10 (Wikipedia) · Fact card
Jupiter gives off more heat than it receives from the Sun.
It is still slowly releasing heat left over from its formation.
Source: Jupiter (Wikipedia) · Fact card
Jupiter would need to be about 80 times more massive to become a star.
That is roughly the minimum mass needed to start hydrogen fusion.
Source: Jupiter (Wikipedia) · Fact card
Thousands of asteroids share Jupiter’s orbit.
The Trojan asteroids gather in two groups ahead of and behind Jupiter. NASA’s Lucy mission launched in 2021 to visit them.
Source: Jupiter trojan (Wikipedia) · Fact card
A NASA spacecraft is on its way to study Europa.
Europa Clipper launched in October 2024 and is due to arrive at Jupiter in 2030.
Source: Europa Clipper (Wikipedia) · Fact card
Europe’s JUICE mission is heading to Jupiter’s icy moons.
The European Space Agency’s probe launched in 2023 and will eventually orbit Ganymede.
Saturn is the sixth planet from the Sun and the second largest.
It is about nine times as wide as Earth.
Source: Saturn (Wikipedia) · Fact card
Saturn’s rings are made mostly of chunks of ice.
The pieces range from tiny grains to boulders as big as houses.
Source: Rings of Saturn (Wikipedia) · Fact card
Saturn’s main rings would stretch most of the way from Earth to the Moon.
The main rings extend up to about 280,000 kilometers across.
Source: Rings of Saturn (Wikipedia) · Fact card
Saturn’s rings seem to disappear every 13 to 16 years.
When Earth passes through the plane of the rings, we see them edge-on and they almost vanish from view. This happened in 2025.
Source: Rings of Saturn (Wikipedia) · Fact card
Galileo thought Saturn had "ears".
His 1610 telescope could not show the rings clearly. Christiaan Huygens first described them as a ring in 1655.
Source: Rings of Saturn (Wikipedia) · Fact card
Saturn’s moon Titan has a thicker atmosphere than Earth.
It is the only moon with a dense atmosphere, made mostly of nitrogen.
Source: Titan (moon) (Wikipedia) · Fact card
Titan has lakes and seas of liquid methane.
It is the only place besides Earth known to have stable liquid on its surface.
Source: Lakes of Titan (Wikipedia) · Fact card
A probe landed on Titan in 2005.
The European Huygens probe touched down after a parachute descent, the most distant landing ever made.
Source: Huygens (spacecraft) (Wikipedia) · Fact card
Saturn’s moon Enceladus shoots water into space.
Geysers at its south pole spray water from an ocean under the ice, and the spray feeds Saturn’s E ring.
Source: Enceladus (Wikipedia) · Fact card
There is a giant hexagon-shaped storm at Saturn’s north pole.
Each side of the six-sided jet stream is longer than Earth is wide.
Source: Saturn’s hexagon (Wikipedia) · Fact card
A day on Saturn lasts about 10.5 hours.
Its fast spin makes the planet bulge noticeably at the equator.
Source: Saturn (Wikipedia) · Fact card
A year on Saturn lasts about 29 Earth years.
It orbits the Sun at an average of about 1.4 billion kilometers.
Source: Saturn (Wikipedia) · Fact card
NASA crashed its Cassini spacecraft into Saturn on purpose.
After 13 years orbiting Saturn, Cassini dove into the planet in 2017 so it could not contaminate moons that might support life.
Source: Cassini-Huygens (Wikipedia) · Fact card
Winds on Saturn can reach about 1,800 km/h.
The fastest winds blow around the equator.
Source: Saturn (Wikipedia) · Fact card
Saturn is made mostly of hydrogen and helium.
Like Jupiter, it has no solid surface to stand on.
Source: Saturn (Wikipedia) · Fact card
Saturn’s moon Mimas looks like the Death Star.
A giant crater, Herschel, covers almost a third of its width.
Source: Mimas (moon) (Wikipedia) · Fact card
Saturn’s moon Iapetus is two-toned.
One side is dark as coal and the other is bright as snow.
Source: Iapetus (moon) (Wikipedia) · Fact card
Saturn is named after the Roman god of farming and wealth.
The day Saturday is also named after Saturn.
Source: Saturn (mythology) (Wikipedia) · Fact card
Saturn was the farthest planet known in ancient times.
It is the most distant planet easily seen without a telescope.
Source: Saturn (Wikipedia) · Fact card
Saturn’s rings may be young, in planetary terms.
Some measurements suggest they could be a few hundred million years old, though this is still debated.
Source: Rings of Saturn (Wikipedia) · Fact card
Saturn’s rings are slowly raining onto the planet.
Ice particles fall into Saturn’s atmosphere, so the rings are gradually losing material.
Source: Rings of Saturn (Wikipedia) · Fact card
Pioneer 11 was the first spacecraft to visit Saturn, in 1979.
Voyager 1 and Voyager 2 followed in 1980 and 1981.
Source: Pioneer 11 (Wikipedia) · Fact card
Small "shepherd moons" keep some of Saturn’s rings in shape.
Moons such as Prometheus and Pandora help confine the narrow F ring.
Source: Rings of Saturn (Wikipedia) · Fact card
Saturn has giant storms that circle the whole planet.
A huge storm in 2010 and 2011 stretched all the way around the northern hemisphere.
Source: Great White Spot (Wikipedia) · Fact card
Gravity at Saturn’s cloud tops is close to Earth’s.
Despite its huge mass, Saturn is so wide and light that its gravity at the cloud tops is only slightly stronger than ours.
Source: Saturn (Wikipedia) · Fact card
NASA plans to fly a drone on Titan.
The Dragonfly rotorcraft mission is planned to launch in 2028 and explore Titan’s surface.
Source: Dragonfly (Titan space probe) (Wikipedia) · Fact card
Saturn’s moon Hyperion looks like a giant sponge.
Its porous, irregular body tumbles chaotically as it orbits.
Source: Hyperion (moon) (Wikipedia) · Fact card
Neptune is the eighth and farthest planet from the Sun.
It orbits about 4.5 billion kilometers from the Sun, around 30 times farther than Earth.
Source: Neptune (Wikipedia) · Fact card
A year on Neptune lasts about 165 Earth years.
It has completed just one orbit since it was discovered in 1846.
Source: Neptune (Wikipedia) · Fact card
A day on Neptune lasts about 16 hours.
Like the other giant planets, it spins much faster than Earth.
Source: Neptune (Wikipedia) · Fact card
Neptune is an "ice giant".
Below its atmosphere it is made largely of water, ammonia and methane in hot, dense forms rather than gas.
Source: Ice giant (Wikipedia) · Fact card
Methane helps make Neptune blue.
Methane in the atmosphere absorbs red light and reflects blue.
Source: Neptune (Wikipedia) · Fact card
Neptune is about four times as wide as Earth.
It is about 17 times as massive as Earth.
Source: Neptune (Wikipedia) · Fact card
Neptune was first seen through a telescope in 1846.
Johann Galle spotted it in Berlin using predictions by Urbain Le Verrier, based on wobbles in Uranus’s orbit.
Source: Discovery of Neptune (Wikipedia) · Fact card
Galileo saw Neptune in 1612 but thought it was a star.
His notes show he recorded it but did not realize it was a planet.
Source: Discovery of Neptune (Wikipedia) · Fact card
Only one spacecraft has ever visited Neptune.
Voyager 2 flew past in August 1989 and sent back the first close-up images.
Source: Voyager 2 (Wikipedia) · Fact card
Neptune had a storm as big as Earth, the Great Dark Spot.
Voyager 2 photographed it in 1989; by 1994 the Hubble Space Telescope found it had disappeared.
Source: Great Dark Spot (Wikipedia) · Fact card
Neptune’s largest moon, Triton, orbits backward.
Triton circles opposite to Neptune’s spin, a sign it was probably captured from the Kuiper Belt.
Source: Triton (moon) (Wikipedia) · Fact card
Triton has geysers of nitrogen.
Voyager 2 saw dark plumes rising several kilometers above its frozen surface.
Source: Triton (moon) (Wikipedia) · Fact card
Triton is one of the coldest places measured in the solar system.
Its surface is about minus 235°C.
Source: Triton (moon) (Wikipedia) · Fact card
Triton is slowly spiraling toward Neptune.
In billions of years it may be torn apart and form a ring.
Source: Triton (moon) (Wikipedia) · Fact card
Neptune has 16 known moons.
Triton holds more than 99% of the mass of all of them combined.
Source: Moons of Neptune (Wikipedia) · Fact card
Neptune has dark, faint rings.
The rings are named after astronomers linked to its discovery, including Galle, Le Verrier and Adams.
Source: Rings of Neptune (Wikipedia) · Fact card
Neptune’s outer ring has clumps named Liberty, Equality and Fraternity.
The arcs in the Adams ring carry the French revolutionary motto, in French: Liberté, Égalité and Fraternité.
Source: Rings of Neptune (Wikipedia) · Fact card
Neptune gives off more than twice the heat it gets from the Sun.
Its internal heat source may drive its extreme winds.
Source: Neptune (Wikipedia) · Fact card
Neptune has seasons that last about 40 years each.
Its axis is tilted about 28 degrees, similar to Earth’s, and its year is 165 Earth years long.
Source: Neptune (Wikipedia) · Fact card
Neptune is named after the Roman god of the sea.
Its astronomical symbol is a trident.
Source: Neptune (mythology) (Wikipedia) · Fact card
Neptune became the farthest planet again in 2006.
When Pluto was reclassified as a dwarf planet, Neptune became the outermost planet.
Source: Pluto (Wikipedia) · Fact card
Pluto is sometimes closer to the Sun than Neptune.
Pluto’s oval orbit crossed inside Neptune’s from 1979 to 1999, but the two never collide.
Source: Pluto (Wikipedia) · Fact card
It may rain diamonds inside Neptune.
Lab experiments suggest the pressure deep inside ice giants could turn carbon into diamonds that sink toward the core.
Source: Neptune (Wikipedia) · Fact card
Gravity at Neptune’s cloud tops is a little stronger than Earth’s.
It is about 1.1 times Earth’s gravity.
Source: Neptune (Wikipedia) · Fact card
Sunlight takes about four hours to reach Neptune.
From Neptune, the Sun looks like a very bright star.
Source: Neptune (Wikipedia) · Fact card
Neptune has its own Trojan asteroids.
Small bodies share its orbit, gathered ahead of and behind the planet.
Source: Neptune trojan (Wikipedia) · Fact card
Neptune’s moon Nereid has one of the most stretched-out orbits of any moon.
Its distance from Neptune varies enormously during each orbit.
Source: Nereid (moon) (Wikipedia) · Fact card
Venus is the second planet from the Sun.
It is the closest planet to Earth in size and is sometimes called Earth’s twin.
Source: Venus (Wikipedia) · Fact card
Venus spins backward.
Compared with most planets, it rotates in the opposite direction, so the Sun rises in the west there.
Source: Venus (Wikipedia) · Fact card
The air pressure on Venus is about 90 times Earth’s.
That is like being about 900 meters under the sea on Earth.
Source: Atmosphere of Venus (Wikipedia) · Fact card
Venus is covered in clouds of sulfuric acid.
The thick clouds reflect sunlight, which is one reason Venus shines so brightly.
Source: Atmosphere of Venus (Wikipedia) · Fact card
Venus’s atmosphere is about 96% carbon dioxide.
This creates a runaway greenhouse effect that traps heat.
Source: Atmosphere of Venus (Wikipedia) · Fact card
The surface of Venus is about 465°C.
That is hot enough to melt lead, day and night.
Source: Venus (Wikipedia) · Fact card
Venus is called the morning star and the evening star.
It is often visible just before sunrise or just after sunset, and ancient people sometimes thought these were two different objects.
Source: Venus (Wikipedia) · Fact card
The first spacecraft to land on another planet landed on Venus.
The Soviet Venera 7 probe touched down in 1970 and sent signals from the surface.
Source: Venera 7 (Wikipedia) · Fact card
The first photos from another planet’s surface came from Venus.
Venera 9 sent back images in 1975 before the heat and pressure destroyed it.
Source: Venera 9 (Wikipedia) · Fact card
No lander has survived on Venus for more than about two hours.
The record is held by Venera 13 in 1982, which lasted about 127 minutes.
Source: Venera 13 (Wikipedia) · Fact card
Venus sometimes crosses in front of the Sun.
Transits of Venus come in pairs eight years apart, more than a century apart. The last was in 2012 and the next is in 2117.
Source: Transit of Venus (Wikipedia) · Fact card
Venus is named after the Roman goddess of love and beauty.
It is the only planet named after a female figure.
Source: Venus (Wikipedia) · Fact card
Venus has more volcanoes than any other planet.
Radar maps show hundreds of large volcanoes, and recent studies suggest some may still be active.
Source: Volcanism on Venus (Wikipedia) · Fact card
Venus’s surface was mapped by radar.
NASA’s Magellan spacecraft mapped almost the whole surface through the clouds in the early 1990s.
Source: Magellan (spacecraft) (Wikipedia) · Fact card
Venus’s clouds race around the planet in about four days.
The upper atmosphere moves about 60 times faster than the planet turns, a pattern called super-rotation.
Source: Atmosphere of Venus (Wikipedia) · Fact card
A year on Venus lasts about 225 Earth days.
Its slow spin means one Venus day lasts about 243 Earth days.
Source: Venus (Wikipedia) · Fact card
Venus comes closer to Earth than any other planet.
At its closest it is about 38 million kilometers away.
Source: Venus (Wikipedia) · Fact card
Venus has phases like the Moon.
Galileo’s observations of these phases in 1610 supported the idea that planets orbit the Sun.
Source: Phases of Venus (Wikipedia) · Fact card
Almost every feature on Venus is named after a woman.
The one main exception is Maxwell Montes, its highest mountain, named after physicist James Clerk Maxwell.
Source: Maxwell Montes (Wikipedia) · Fact card
Scientists have debated for decades whether Venus has lightning.
Spacecraft have recorded radio bursts that may be lightning, but the evidence is still argued over.
Source: Atmosphere of Venus (Wikipedia) · Fact card
A 2020 study sparked debate about possible life in Venus’s clouds.
Astronomers reported phosphine, a gas linked to life on Earth, but later studies disputed the detection.
Source: Phosphine (Wikipedia) · Fact card
New missions to Venus are planned.
NASA’s VERITAS and DAVINCI and Europe’s EnVision are being developed to study the planet.
Source: EnVision (Wikipedia) · Fact card
On Venus, the time from one sunrise to the next is about 117 Earth days.
Its backward spin and orbit combine to give a solar day shorter than its rotation.
Source: Venus (Wikipedia) · Fact card
You cannot see Venus’s surface with a normal telescope.
Its clouds hide the surface completely; we see it only with radar or by landing.
Source: Venus (Wikipedia) · Fact card
Venus has strange flat volcanoes called pancake domes.
They were formed by thick, sticky lava and can be tens of kilometers across.
Source: Pancake dome (Wikipedia) · Fact card
Much of Venus’s surface may be relatively young.
Few craters suggest the surface was largely resurfaced by volcanic activity within the last several hundred million years.
Source: Geology of Venus (Wikipedia) · Fact card
The Sun is a fairly ordinary star called a yellow dwarf.
Astronomers class it as a G-type main-sequence star. Its light is actually white; the atmosphere makes it look yellow from Earth.
Source: Sun (Wikipedia) · Fact card
The Sun is about 4.6 billion years old.
It is roughly halfway through its life as a main-sequence star.
Source: Sun (Wikipedia) · Fact card
In about 5 billion years the Sun will swell into a red giant.
It will then shed its outer layers and end as a small, dense white dwarf.
Source: Sun (Wikipedia) · Fact card
The Sun’s core is about 15 million °C.
There, hydrogen fuses into helium, releasing the energy that makes sunlight.
Source: Solar core (Wikipedia) · Fact card
The Sun’s surface is about 5,500 °C.
The visible surface, the photosphere, is far cooler than the core.
Source: Photosphere (Wikipedia) · Fact card
The Sun’s outer atmosphere is hotter than its surface.
The corona reaches over a million degrees, and why it is so hot is still being studied.
Source: Stellar corona (Wikipedia) · Fact card
The Sun is made mostly of hydrogen and helium.
By mass it is about 73% hydrogen and 25% helium.
Source: Sun (Wikipedia) · Fact card
The Sun turns about 4 million tonnes of matter into energy every second.
This is the mass lost as hydrogen fuses into helium in its core.
Source: Sun (Wikipedia) · Fact card
Energy made in the Sun’s core can take thousands of years to reach the surface.
It is absorbed and re-emitted countless times on its way out, then reaches Earth in about eight minutes.
Source: Sun (Wikipedia) · Fact card
Sunspots are cooler, darker patches on the Sun.
They are caused by strong magnetic fields and can be larger than Earth.
Source: Sunspot (Wikipedia) · Fact card
The Sun has an activity cycle of about 11 years.
Sunspots, flares and eruptions rise and fall over each cycle.
Source: Solar cycle (Wikipedia) · Fact card
The northern and southern lights are caused by the Sun.
Charged particles from the Sun hit Earth’s magnetic field and make gases in the upper atmosphere glow.
Source: Aurora (Wikipedia) · Fact card
The Sun constantly blows a stream of particles into space.
This solar wind travels at hundreds of kilometers per second and fills the solar system.
Source: Solar wind (Wikipedia) · Fact card
A solar storm in 1859 made telegraph lines spark.
The Carrington Event produced auroras seen near the tropics and disrupted telegraph systems.
Source: Carrington Event (Wikipedia) · Fact card
The Sun spins faster at its equator than near its poles.
The equator turns about once every 25 days, the poles about every 35.
Source: Solar rotation (Wikipedia) · Fact card
The Sun is about 400 times wider than the Moon and about 400 times farther away.
That coincidence is why the Moon can just cover the Sun in a total solar eclipse.
Source: Solar eclipse (Wikipedia) · Fact card
Never look straight at the Sun, even during an eclipse.
It can permanently damage your eyes. Use certified eclipse glasses or a pinhole projector.
Source: Solar eclipse (Wikipedia) · Fact card
A spacecraft has flown through the Sun’s atmosphere.
NASA’s Parker Solar Probe became the closest human-made object to the Sun and, in December 2024, passed about 6 million kilometers from its surface.
Source: Parker Solar Probe (Wikipedia) · Fact card
The Sun orbits the center of the Milky Way.
One trip around the galaxy takes about 230 million years.
Source: Sun (Wikipedia) · Fact card
Almost all life on Earth depends on energy from the Sun.
Plants capture sunlight through photosynthesis, and it drives our weather and climate.
Source: Sunlight (Wikipedia) · Fact card
Your skin makes vitamin D using sunlight.
Ultraviolet B rays trigger vitamin D production, which helps keep bones healthy.
Source: Vitamin D (Wikipedia) · Fact card
Solar flares release enormous energy in minutes.
The biggest can disturb radio communications and GPS on Earth.
Source: Solar flare (Wikipedia) · Fact card
The Latin word for the Sun is "sol".
That is where words like "solar" come from. Sunday is named after the Sun.
Source: Sun (Wikipedia) · Fact card
The average distance from Earth to the Sun is about 150 million kilometers.
Astronomers call this distance one astronomical unit (AU).
Source: Astronomical unit (Wikipedia) · Fact card
Earth is closest to the Sun in early January.
Seasons are caused by Earth’s tilt, not its distance from the Sun.
Source: Perihelion and aphelion (Wikipedia) · Fact card
Sunlight contains every color of the rainbow.
A prism or raindrops split white sunlight into its colors.
Source: Sunlight (Wikipedia) · Fact card
Earth lights up the Moon’s dark side.
Sunlight reflected off Earth, called earthshine, makes the unlit part of a crescent Moon faintly visible.
Source: Earthshine (Wikipedia) · Fact card
Venus may once have had water on its surface.
Some studies suggest early Venus could have had shallow oceans before a runaway greenhouse effect boiled them away, though this is still debated.
Source: Venus (Wikipedia) · Fact card
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