Space & Planets
Tap a card to fly there The Sun · The Moon · Earth · Mars · Jupiter · Saturn · Comets · Astronauts · Telescopes · The Milky Way · Mercury · Venus · Uranus · Neptune · Pluto · Ceres · Eris · Dwarf Planets · The Solar System · Order of the Planets. Everything you see in the night sky is a real place.
Ages 7–10
What's inside
The Sun — our own star
The Sun is a star, exactly like the ones that twinkle at night — it just happens to be the closest one to us. It is a giant ball of glowing gas, and it is not on fire the way a candle is. It makes its light and warmth deep in its middle.
The Moon — our closest neighbour
The Moon is a rocky world that circles the Earth, about a quarter as wide as our planet. It has no air, no wind and no weather. It does not make its own light — it is simply catching sunlight and bouncing it back at you.
Earth — the only home we have
Earth is the third planet out from the Sun, and the only place anyone has ever found life. It is a ball of rock with a thin skin of air around it and oceans sloshing on top. From space it looks blue, white and green.
Mars — the rusty red planet
Mars is the next planet out after Earth, and it looks orange-red because its dust is full of rust — the same stuff that makes an old bike go orange. It has mountains, valleys, ice caps and enormous dust storms. Nobody has stood there yet, but our robots have.
Jupiter — the giant of them all
Jupiter is by far the biggest planet, so big that all the other planets together would still not match it. It is a gas giant, which means there is no solid ground to stand on — only deeper and deeper layers of cloud. Its stripes are bands of storm racing round the planet.
Saturn — the one with the rings
Saturn is the second biggest planet and the show-off of the Solar System, wrapped in the brightest rings anyone has ever seen. Like Jupiter it is a giant made of gas, with no surface to land on. Through even a small telescope, those rings snap into view and never stop being astonishing.
Comets — snowballs with tails
A comet is a lump of ice, dust and rock, usually only a few kilometres across, left over from when the planets were forming. Most of the time it drifts far out in the cold and does nothing at all. Then its orbit brings it close to the Sun, and it puts on a show.
Astronauts — people who live in orbit
Astronauts are ordinary people with extraordinary training who go and live in space for months at a time. Most of them stay on the International Space Station, a laboratory the size of a football pitch flying around the Earth. It has been lived in without a break since November 2000.
Telescopes — light buckets for your eyes
A telescope does not really magnify the sky so much as gather light. Your eye has a tiny opening; a telescope has a big lens or mirror that scoops up thousands of times more, so faint things suddenly become visible. Point one at a fuzzy dot and it turns into a planet with moons.
The Milky Way — our address in space
The Milky Way is not something you look at from outside — it is the place you are standing in. Because we sit inside its flat disc, we see it edge-on, as a pale milky stripe running right across the sky. That stripe is the reason it got its name, thousands of years before anyone knew what it was.
Mercury — the little scorched planet
Mercury is the smallest planet and the one nearest the Sun. It is a bare ball of grey rock covered in craters, with almost no air to hold in heat. That is why it has the wildest temperatures of any planet — burning hot on the sunny side and freezing cold in the dark.
Venus — the hottest planet of all
Venus is almost the same size as Earth, so it is sometimes called our twin. But it is nothing like a friendly twin: it is wrapped in thick, poisonous clouds and its air presses down harder than the deep sea. Under those clouds it is the hottest planet in the whole Solar System.
Uranus — the planet that rolls on its side
Uranus is a giant world made mostly of icy gases, four times wider than Earth and a soft blue-green colour. It is famous for one very odd habit: instead of spinning upright, it lies right over on its side and rolls around the Sun like a ball. It is so far away that you need a telescope to spot it.
Neptune — the windy blue giant far away
Neptune is the last of the eight planets, a deep-blue ice giant so far out that the Sun looks like just a very bright star from there. It is a windy, stormy world with no solid ground to stand on. It was the first planet found not by looking, but by working out with maths where it had to be.
Pluto — the famous little dwarf planet
Pluto is a small, icy world far out past Neptune, on the frozen edge of our Solar System. For a long time it was called the ninth planet, but scientists later decided it is a dwarf planet — one of a whole family of little worlds out there. It is so far away that sunlight takes over five hours to reach it.
Ceres — the round dwarf in the asteroid belt
Ceres is the biggest object in the asteroid belt, the ring of rocks that circles between Mars and Jupiter. It is round like a little planet, so it counts as a dwarf planet too. Even though it is the giant of the belt, it is still much smaller than any of the eight planets.
Eris — the faraway dwarf that shook things up
Eris is a far-off dwarf planet out in the icy edges of the Solar System, even more distant than Pluto. It is about the same size as Pluto, and when it was found in 2005 it caused a big rethink. Astronomers realised there could be many such worlds, and that is when they decided how to sort planets from dwarf planets.
Dwarf Planets — the small round worlds
Dwarf planets are worlds that are round like a proper planet but too small to be one of the main eight. To count as a full planet, a world must have swept its path clear of other rocks — and dwarf planets share their neighbourhood with lots of leftover chunks. So they get their own special group.
The Solar System — the Sun and its whole family
The Solar System is the Sun together with everything held by its gravity: eight planets, their many moons, and swarms of asteroids, comets and dwarf planets. The Sun sits in the middle, and everything else circles around it. It is our whole cosmic neighbourhood, and Earth is just one small part of it.
Order of the Planets — the eight in a row from the Sun
Starting from the Sun and moving outward, the eight planets go: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. The first four are small and rocky, and the last four are huge balls of gas and ice. Knowing the order helps you picture where our own Earth sits in the line-up.
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