GO UNIVERSE GO

Blast Off to Your Space Adventure!

Launch your rocket, explore amazing planets, and discover awesome space facts in the coolest learning game ever.

Launch Rockets

Explore Planets

Learn Facts

What kids are saying

"Have you found space yet?"

Emma, age 7 · Jan 2026

"I'm in space already!"

Liam, age 9 · Jan 2026

"Can you make Mars bigger, it's hard to find!"

Noah, age 6 · Feb 2026

What you'll discover

20+ destinations

Explore 9 planets with 3D surfaces, a hyperspace station, and 11 deep space locations like black holes, pulsars, and nebulae.

380+ space facts

NASA-sourced facts about planets, stars, black holes, and more, all written for kids to understand.

Zero cost, zero ads

Completely free. No accounts, no downloads, no advertising. Just learning.

Works everywhere

Desktop, tablet, or phone. Touch controls, voice narration, and keyboard support built in.

Solar system facts for kids

Discover amazing facts about every planet in our solar system. Launch the game above to explore each world in 3D.

Mercury

Hot AND Cold!

Mercury has the wildest temperature swings of any planet! The sunny side can reach 800 degrees Fahrenheit (hot enough to melt lead!), but the dark side drops to minus 290 degrees! That is a difference of over 1,000 degrees!

Ice on a Hot Planet!

Believe it or not, there is ICE on Mercury! Deep inside craters at Mercury's north and south poles, the Sun's rays never reach the bottom. These permanently shadowed spots are cold enough to keep water ice frozen forever!

A Weird Year!

A year on Mercury is only 88 Earth days long, but a single Mercury day-night cycle takes 176 Earth days! That means a Mercury day is actually LONGER than a Mercury year!

The Tiniest Planet!

Mercury is the smallest planet in our solar system! It is only about 3,032 miles across - that is smaller than some moons! Jupiter's moon Ganymede and Saturn's moon Titan are both bigger than Mercury!

See all 20 Mercury facts →

Venus

The Hottest Planet!

Venus is the hottest planet in the entire solar system, even hotter than Mercury which is closer to the Sun! The surface temperature is about 900 degrees Fahrenheit (475 degrees Celsius) - hot enough to melt lead!

It Spins Backwards!

Venus is the only planet that spins backwards compared to most other planets! On Venus, the Sun rises in the WEST and sets in the EAST - the opposite of Earth! Scientists think a giant space collision billions of years ago may have flipped Venus upside down!

Volcano World!

Venus has more volcanoes than any other planet in the solar system - over 1,600 major volcanoes and possibly thousands more small ones! Scientists think some of them might still be active today.

Landing on Venus!

The Soviet Union sent several Venera spacecraft that actually landed on Venus in the 1970s and 1980s! They took the only photos ever from the surface of Venus. But the extreme heat and pressure destroyed each lander in less than 2 hours!

See all 20 Venus facts →

Earth

The Blue Marble

Earth is the only planet known to have liquid water on its surface! About 71% of Earth's surface is covered by oceans. From space, our planet looks like a beautiful blue marble floating in the darkness.

Perfect for Life!

Earth sits in the "Goldilocks zone" - not too hot, not too cold, but just right for life! It is the only planet we know of that has plants, animals, and people living on it.

A Giant Magnet!

Earth has a powerful magnetic field created by its spinning iron core! This invisible shield protects us from harmful solar radiation and creates the beautiful Northern and Southern Lights.

One Big Moon!

Earth's Moon is the fifth largest moon in the solar system! It is about one-quarter the size of Earth and is the only other world humans have ever walked on. The Moon controls our ocean tides!

Mars

Blue Sunsets!

On Mars, sunsets look BLUE instead of red and orange like on Earth! Martian dust in the air scatters light in a special way that turns the sky blue near the sun at sunset.

Tallest Volcano Ever!

Olympus Mons is the tallest volcano in the entire solar system! It is 3 times taller than Mount Everest and as wide as the entire state of Arizona! It is so huge that if you stood on top, you could not even see the edges.

Two Potato Moons!

Mars has two tiny moons named Phobos and Deimos, which mean "fear" and "dread" in Greek! They are not round like our Moon - they look like lumpy potatoes!

First Mars Helicopter!

NASA's Ingenuity helicopter made history by being the first aircraft ever to fly on another planet! It completed 72 flights on Mars before its mission ended in 2024.

See all 20 Mars facts →

Jupiter

The Great Red Spot

Jupiter has a giant storm called the Great Red Spot. It is bigger than Earth and has been raging for more than 300 years! Winds inside reach 335 miles per hour! Juno found its roots go 200 miles deep!

Almost a Star!

Jupiter is made of the same stuff as the Sun: hydrogen and helium! If it had been about 80 times more massive, it could have become a star instead of a planet!

Europa's Hidden Ocean

Jupiter's moon Europa has a huge ocean of liquid water hiding under thick ice! Scientists think alien life might swim in that ocean! NASA's Europa Clipper launched in 2024 to investigate!

LEGO in Space!

NASA's Juno spacecraft carries three special aluminum LEGO minifigures: the Roman god Jupiter, his wife Juno, and the scientist Galileo! They are orbiting Jupiter right now!

See all 27 Jupiter facts →

Saturn

It Would Float!

Saturn is so light and fluffy that if you found a bathtub big enough, Saturn would actually FLOAT in water! It is the only planet in our solar system that would do this. It is less dense than water!

Huge But Super Thin!

Saturn's rings stretch out 175,000 miles wide - that is nearly as far as from Earth to the Moon! But they are only about 30 feet thick. That is like a piece of paper compared to a football field!

The Hexagon Storm!

At Saturn's north pole, there is a giant six-sided storm called the Hexagon. It is wider than two Earths! A perfect six-sided shape spinning in space - scientists are still figuring out why it looks like that!

Titan's Liquid Lakes!

Titan has lakes, rivers, and seas on its surface - just like Earth! But instead of water, they are filled with liquid methane. It rains methane there too!

See all 20 Saturn facts →

Uranus

The Sideways Planet!

Uranus spins completely on its side! Its axis is tilted a whopping 98 degrees. Scientists think something huge - maybe an Earth-sized object - crashed into Uranus billions of years ago and knocked it over!

It Rains Diamonds!

Deep inside Uranus, the pressure is so incredibly intense that it squeezes carbon atoms into actual diamonds! Scientists believe it literally rains diamonds inside this planet.

The Coldest Planet!

Uranus holds the record for the coldest temperature ever measured on a planet in our solar system: minus 371 degrees Fahrenheit! That is even colder than Neptune, even though Neptune is farther from the Sun!

First Planet Discovered!

Uranus was the first planet ever discovered using a telescope! William Herschel found it in 1781. At first he thought it was a comet or a star, but it turned out to be a whole new planet!

See all 20 Uranus facts →

Neptune

Fastest Winds in the Solar System!

Neptune has the fastest winds of ANY planet - they blast at over 1,200 miles per hour! That is almost twice the speed of sound! Even the most powerful hurricanes on Earth are gentle breezes compared to Neptune!

Discovered With Math!

Neptune is the only planet that was discovered using math before anyone even saw it! Scientists noticed that Uranus was wobbling in a strange way, so they calculated that another planet must be pulling on it.

Triton: The Backwards Moon!

Neptune's biggest moon Triton orbits BACKWARDS compared to Neptune's spin! Scientists think Triton was actually a dwarf planet from the Kuiper Belt that Neptune captured with its gravity long ago!

165-Year Orbit!

Neptune takes about 165 Earth years to go around the Sun just once! Since Neptune was discovered in 1846, it has only completed ONE full orbit! It finished its first known trip around the Sun in 2011!

See all 20 Neptune facts →

The Sun

Incredibly Huge!

The Sun is so big that about 1.3 million Earths could fit inside it! Its diameter is about 864,000 miles - that is 109 times wider than Earth!

Insanely Hot Core!

The core of the Sun reaches 27 million degrees Fahrenheit (15 million degrees Celsius)! That is where nuclear fusion happens, smashing hydrogen atoms together to make helium and energy!

Super Heavy!

The Sun contains 99.86% of all the mass in our entire solar system! Everything else - all the planets, moons, asteroids, and comets - makes up only 0.14%!

Parker Solar Probe!

NASA's Parker Solar Probe launched in 2018 and has flown closer to the Sun than any spacecraft ever! It has reached speeds over 400,000 mph, making it the fastest human-made object!

See all 20 Sun facts →