Our Solar System

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

Mnemonic: 'My Very Educated Mother Just Served Us Nachos.' The initials stand for Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.

💡 Did you know? The four inner planets are rocky worlds, the four outer ones are gas and ice giants.

Mercury

Mercury orbits the Sun in just 88 days: faster than any other planet. It has almost no real atmosphere.

💡 Did you know? Despite being nearest the Sun, it is not the hottest planet; that is Venus.

Venus

Its dense CO₂ atmosphere causes an extreme greenhouse effect. It is about the size of Earth and is often called Earth's 'sister planet'.

💡 Did you know? In the night sky Venus is the brightest object after the Moon: the 'evening' or 'morning star'.

Earth

About 71 percent of its surface is covered by water; liquid water is considered essential for life.

💡 Did you know? Earth is the only planet not named after a Greek or Roman deity.

Mars

Mars has a thin atmosphere and two small moons, Phobos and Deimos. It is a prime target for space exploration.

💡 Did you know? Mars is home to Olympus Mons, the tallest known mountain in the Solar System.

Jupiter

Jupiter is so big that all the other planets together would fit inside it. Its 'Great Red Spot' is a storm larger than Earth.

💡 Did you know? Jupiter has over 90 known moons: only Saturn has more.

Saturn

The rings are made of countless chunks of ice and rock. Saturn is so light it would float in a giant tub of water.

💡 Did you know? Jupiter, Uranus and Neptune have rings too: but far fainter ones.

Uranus

Uranus is an icy gas planet and looks pale blue-green because of methane in its atmosphere.

💡 Did you know? Uranus was the first planet discovered with a telescope, in 1781.

Neptune

The blue gas giant has the fastest winds in the Solar System: over 2000 km/h. One orbit takes it about 165 years.

💡 Did you know? Neptune was first predicted by calculation in 1846 and then found exactly where predicted.

Mercury

Mercury looks grey and heavily cratered: its surface resembles the Moon, dotted with impact craters.

💡 Did you know? With no protective atmosphere, the craters have survived for billions of years.

Venus

Venus appears as an evenly cream-white to yellow sphere: you only ever see its thick cloud cover, never the surface.

💡 Did you know? The yellowish colour comes from clouds of sulfuric acid.

Earth

Earth is recognisable by its blue water, white clouds and brown-green continents: the ‘blue planet’.

💡 Did you know? The famous ‘Blue Marble’ photo was taken in 1972 on the way to the Moon.

Mars

Mars is known by its rusty-red, desert-like surface and bright icy polar caps.

💡 Did you know? The polar caps are partly made of frozen carbon dioxide (dry ice).

Jupiter

Jupiter is recognisable by its light and dark cloud bands and the ‘Great Red Spot’.

💡 Did you know? The bands are cloud currents flowing east-west.

Saturn

Saturn is unmistakable thanks to its wide, bright ring system.

💡 Did you know? Seen edge-on, the rings are so thin they almost disappear.

Uranus

Uranus shows up as a smooth, pale blue-green sphere with almost no visible features.

💡 Did you know? The colour comes from methane, which absorbs red light.

Neptune

Neptune appears as a deep-blue sphere: similar to Uranus but a stronger blue, with a few bright clouds.

💡 Did you know? In 1989 Voyager 2 photographed a dark storm, the ‘Great Dark Spot’.

Sun

The Sun is a star and holds over 99% of the Solar System's mass. It is made mostly of hydrogen and helium and produces energy by nuclear fusion.

💡 Did you know? The Sun's core reaches about 15 million degrees Celsius.

Moon

The Moon's gravity causes the tides, and because of tidal locking it always shows us the same side.

💡 Did you know? In 1969 Apollo 11 landed the first humans on the Moon.

Pluto

Pluto is smaller than Earth's Moon and orbits in the Kuiper Belt beyond Neptune.

💡 Did you know? In 2015 the New Horizons probe returned the first sharp images of Pluto.

Dwarf planet

A dwarf planet orbits the Sun and is rounded by its own gravity, but (unlike a planet) has not cleared its orbit of other objects.

💡 Did you know? They include Pluto, Ceres, Eris, Makemake and Haumea.

Asteroid belt

Millions of small rocky and metallic bodies orbit there; the largest is the dwarf planet Ceres.

💡 Did you know? Despite the many objects, the belt is so empty that spacecraft cross it safely.

Comet

As a comet nears the Sun its ice vaporises and forms a tail that always points away from the Sun.

💡 Did you know? Halley's Comet returns about every 76 years: last in 1986, next in 2061.

Meteor

If a body burns up completely only the streak remains; if a piece reaches the ground it is called a meteorite.

💡 Did you know? During "meteor showers" Earth crosses the dust trail of a comet.

Milky Way

The Milky Way is a spiral galaxy with hundreds of billions of stars; the Sun is one of them.

💡 Did you know? The Sun takes about 225 million years to orbit the centre of the Milky Way once.

Gravity

The Sun's enormous mass holds all the planets on elliptical orbits. Johannes Kepler described these orbits as ellipses.

💡 Did you know? Isaac Newton showed that the same force makes an apple fall and the Moon orbit.

Ganymede

Ganymede is even larger than the planet Mercury and has its own magnetic field.

💡 Did you know? Galileo Galilei discovered Jupiter's four large moons in 1610: now called the "Galilean moons".

Sun

The Sun appears as a dazzling, yellowish-white disc: sometimes with dark sunspots.

💡 Did you know? Sunspots are cooler, darker regions on the Sun's surface.

Moon

The Moon is a grey, crater-covered sphere with dark patches: the "lunar seas" of solidified lava.

💡 Did you know? The dark "seas" (maria) are actually dry plains of ancient lava.

Pluto

Pluto shows a brownish, pale surface with a large, heart-shaped bright plain.

💡 Did you know? That heart-shaped region is called "Tombaugh Regio", after Pluto's discoverer Clyde Tombaugh.