WELCOME TO SPACE
Wait, what? A goldilocks planet is a planet in the habitable zone around a star. It’s not so close that all the water burns away, and not so far away that everything freezes. Like Baby Bear’s porridge, its temperature is ‘just right’ for life. Scientists think there could be over 40 billion Goldilocks planets in the universe!
By Lizzie Cresswell Illustration by Louise Hannaford
In the 1920s, the astronomer Edwin Hubble came up with a brilliant new theory. But there was so much energy and heat, the bubble exploded! The universe began to stretch and grow, and particles began to collide and come together.
He had been studying the stars through his telescope, and saw they were moving away from Earth. In fact, the further away they were, the faster they were moving. Hubble thought this was because the universe is still expanding.
Over billions of years, all kinds of space phenomena were created. If you were to travel into space today, here’s what you might find:
90 years ago, this caused quite a stir! Nobody knew how vast space was, or that there are galaxies outside of ours.
Planets For a planet to be a planet, it must do three things: travel around a star, be big enough that its gravity makes it round, and be big enough to clear away any neighbouring objects.
Today we know lots about space, and we’ve sent people, spacecraft and satellites up to explore it. Hubble’s theory gave us some clues to why the universe looks like it does today… The Big Bang Everything in the universe is moving apart, which means it was once all together. 14 billion years ago, atoms, particles and gases were all squashed into a bubble smaller than the head of a pin.
The Earth is a goldilocks planet, but other planets are very different. Some are huge, hot and rocky, others tiny and frozen. Our solar system has eight planets, of which Jupiter is the largest – a huge gas giant. Jupiter is so big that you could fit 1,300 Earths into it!
Wait, what? An astronomer is a scientist who studies natural objects in space, like stars, planets, comets and moons.
Satellites In 1957, Russia sent the first man-made satellite, Sputnik 1, into space. Since then, we’ve sent up lots more. They beam us TV shows, weather images, navigation data and much more.
Comets Comets are big clumps of dirt, rocks and ice that orbit the Sun. When they get too close, they produce gases that burst into flames – giving them a huge burning head and long ‘tail’ of fire.
Moons Moons are natural satellites that orbit planets. (There’s a lot of orbiting in space!) Some planets have more than others. We only have one Moon, but Saturn has 82.
Astronomer Caroline Herschel discovered eight comets in the 1700s, including the 35P/Herschel– Rigollet comet. It has an orbit of 155 years, so we won’t see it again until 2092! Black holes If you were travelling into space, you’d be better off avoiding these! When a really big star burns out, the gravity around it is so strong that it collapses in on itself. That sometimes creates a black hole. It’s an area of gravity that’s so strong, nothing can escape it – not even light. Spooky stuff!
Stars There are lots of myths and legends about stars. In Greek mythology, the constellations were thought to be outlines of animals, people or objects placed there by the Gods. Now, we know each star is a huge ball of gases that has been burning for billions of years. And not all stars are seen at night. We can only see the closest star to us during the day – the Sun. Stars come in all different sizes and colours. The largest supergiants can be over 1,500 times bigger than our Sun, while the smallest neutron stars are about as big as a city. But the bigger a star, the cooler it is, as it’s more spread out.
6
7