Space & Astronomy

eight

Since 2006 there are counted eight planets: from Mercury to Neptune. Pluto was reclassified as a 'dwarf planet' back then.

💡 Did you know? Four inner rocky planets and four outer gas giants make up the system.

Mercury

Mercury orbits the Sun in just 88 days. Despite being closest to the Sun, it is not the hottest planet; that is Venus.

💡 Did you know? On Mercury temperatures swing from over +400 °C by day to below −170 °C at night.

Jupiter

Jupiter is so large that all the other planets together would fit inside it. As a gas giant it has no solid surface.

💡 Did you know? Its 'Great Red Spot' is a storm that has raged for centuries and is larger than Earth.

Saturn

Saturn's spectacular rings are made of countless chunks of ice and rock. Other gas giants have rings too, but none so striking.

💡 Did you know? Saturn is so light that it would float in a giant tub of water.

Sun

The Sun is a star and holds over 99% of the entire mass of the Solar System. In its core hydrogen fuses into helium, releasing its energy.

💡 Did you know? About 1.3 million Earths would fit inside the Sun.

Milky Way

Our galaxy contains hundreds of billions of stars. The Sun is just one of them, far out in one of the spiral arms.

💡 Did you know? For a single lap around the galactic centre the Sun needs about 225 million years.

Big Bang

According to the Big Bang theory the universe arose about 13.8 billion years ago from an extremely hot, dense state and has been expanding ever since.

💡 Did you know? The 'afterglow' of the Big Bang is still measurable today as faint background radiation.

Mars

Mars owes its red colour to iron-rich dust (rust) on its surface. There are signs that water once flowed there.

💡 Did you know? It hosts Olympus Mons: at about 22 km the tallest known volcano in the Solar System.

distance

A light-year is not a unit of time but of distance: how far light travels in one year: about 9.5 trillion kilometres.

💡 Did you know? We see distant stars as they looked years ago: their light has been travelling for a long time.

Moon

The Moon is Earth's only natural satellite and responsible for the tides. It always shows us the same side.

💡 Did you know? The Moon drifts a few centimetres farther from Earth every year.

1971

In 1971 the Soviet Union placed the first space station, Salyut 1, into orbit: an early step towards permanent life in space.

💡 Did you know? Its first crew died tragically on the way back through a loss of pressure in the capsule.

1975

In 1975 European states joined together to form ESA, to conduct spaceflight jointly. It launches satellites and probes and takes part in the ISS.

💡 Did you know? ESA operates its own Ariane rockets, which launch from French Guiana.

1986

In 1986 the US shuttle Challenger broke apart shortly after launch; all seven astronauts died. The cause was a sealing ring that failed in the cold.

💡 Did you know? On board was a teacher meant to be the first 'ordinary' civilian in space.

1990

In 1990 the Hubble telescope was placed into orbit. Free of the disturbing atmosphere, it has delivered razor-sharp images of space for decades.

💡 Did you know? At first its mirror was ground incorrectly: astronauts had to repair it in space.

1997

In 1997 Mars Pathfinder landed on the red planet and released the small rover 'Sojourner': the first roving vehicle on Mars.

💡 Did you know? The landing was cushioned by giant airbags that bounced across the ground.

1998

In 1998 the assembly of the ISS began with its first module: a joint project of many nations. It orbits Earth at about 400 km altitude.

💡 Did you know? The ISS circles Earth roughly every 90 minutes: the crew sees 16 sunrises and sunsets a day.

2000

Since November 2000 the ISS has been continuously inhabited: one of the longest unbroken human presences off Earth.

💡 Did you know? So for over two decades there has always been at least one human in space.

2001

In 2001 US millionaire Dennis Tito flew to the ISS as the first paying tourist. He is said to have paid around 20 million dollars for it.

💡 Did you know? He paved the way for today's commercial space tourism.

2003

In 2003 the shuttle Columbia broke apart on re-entry; all seven astronauts died. At launch a piece of insulating foam had come loose and damaged the heat shield.

💡 Did you know? After the disaster the Space Shuttle programme was ended a few years later.

2003

In 2003 China put its first person into space with Shenzhou 5, becoming the third independent spacefaring nation after the USSR and the USA.

💡 Did you know? The astronaut Yang Liwei was celebrated as a national hero in China.