Space Facts for Kids
Out-of-this-world facts about the universe
Space is not a perfect vacuum. Every cubic metre of interstellar space contains roughly one atom of hydrogen, making it extraordinarily sparse but not truly empty.
Despite surface temperatures that can reach 430 degrees Celsius, Mercury has ice at its poles, hidden in permanently shadowed craters where sunlight never reaches.
The Sun is made up of about 73 per cent hydrogen and 25 per cent helium. Every second, it converts around 600 million tonnes of hydrogen into helium through nuclear fusion.
During the day, the Martian sky appears a dusty butterscotch colour because fine iron-oxide particles in the atmosphere scatter red light.
Stars appear to twinkle because Earth's atmosphere bends and distorts their light. In space, astronauts see stars as steady, unblinking points of light.
Sunsets on Mars appear blue. The fine dust particles in the Martian atmosphere scatter blue light more effectively near the direction of the Sun.
The upper atmosphere of Uranus contains hydrogen sulphide, the same compound that gives rotten eggs their terrible smell.
A single day on Mercury (one full rotation on its axis) lasts about 59 Earth days, while a full orbit around the Sun takes only 88 Earth days.
Scientists estimate there are at least two trillion galaxies in the observable universe — roughly 250 times more galaxies than people on Earth.
On Venus, it rains sulphuric acid. However, the drops evaporate before reaching the surface because the lower atmosphere is so intensely hot.