Skip to 0 minutes and 8 seconds In this hospital in the sky, which we call a nebula, baby stars are being born. At the centre of these cots of gas and dust, stars are coming to life as they begin to produce their own light. We can use special cameras to see them hiding behind the dust. Young planets and moons form from the disc of material around each star. Though, just like humans, stars born at the same time can be very different to one another. Meet Otis who is a big blue extremely hot O-type star. Otis is 60 times more massive than our sun, and can be wild and hot-tempered, huffing and puffing to give off the strongest stellar winds and throwing his material out into space.
Skip to 0 minutes and 53 seconds Stars like Otis are rare. And to their energetic behaviour, they only live for a few million years. Otis will end his life with a violent supernova explosion and turn into a black hole. We definitely wouldn’t want to be living on a planet around a star like Otis.
Skip to 1 minute and 13 seconds Georgie is a G-type star and was born in the same nebula. Georgie is a small hot yellow star, but not as hot as Otis, and nowhere near as bright. She’s far calmer than Otis, but still has a few tantrums, letting off her frustration as strong winds and flares. Georgie will live for 10 billion years, after which, she’ll expand into a red giant star and throw off her outer layers of gas to form a beautiful nebula. Our sun is a lot like Georgie. We’ve got another five billion years until our sun expands into a red giant growing to swallow up Mercury and Venus and eventually scorching the Earth. It will end its life as a small, white dwarf star.
Skip to 2 minutes and 0 seconds And this is Markus, who’s a much smaller, cooler, red M-type star. Almost three quarters of the stars in our galaxy are like Markus, but they’re so dim, we can’t see them without a telescope. Although he still has lots of wild flares, Marcus’s slow and stingy use of fuel means he live for trillions of years. A planet around the starlight Markus could be an ideal home for us after it becomes too hot for us to live on Earth. We could live happily for trillions of years if we find a world that has the right temperature for liquid water and a suitable atmosphere for us to breathe.
Skip to 2 minutes and 39 seconds Maybe we could watch the sun evolve to the next stage of its life and to the leftovers of our solar system will become a nursery for the next family of stars.
How will the world end?
The Story of Stars video is aimed at children aged 7 to 11 and introduces them to the lifecycles of three different stars: Otis, Georgie and Markus. Here are the main stages in a star’s life:
- Stars are formed in a giant cloud of gas and dust called a nebula. There is a famous stellar nursery called the Orion Nebula, visible in the sword of the constellation Orion.
- Our Sun and solar system formed in a nebula 4.5 billion years ago.
- Some stars get really big, really hot and really bright - they shine blue. They have the shortest lifetimes.
- Some stars are medium-sized like the Sun, they are much cooler than the big blue stars and they appear yellow.
- Other stars are smaller, dimmer and cooler than the Sun, they appear orange/red and have the longest lifetimes.
- Eventually stars run out of fuel and they change. All stars expand and become red giant stars. The Sun will turn into a red giant in around 5 billion years time - its surface will reach the orbit of the Earth.
- Big blue stars explode - this is called a supernova. Medium yellow and small red stars lose their outer layers over hundreds of thousands of years forming a colourful nebula of their own.
- Big blue stars eventually become very small, very heavy glowing stars called neutron stars. Or they become black holes.
- Yellow Sun-like stars and small red stars eventually become small white dwarf stars which eventually fizzle away to become black dwarf stars.
- All of the material left over from these stars is used to form more baby stars, and planets and maybe life!
Think about ways you could teach your pupils about different stars - could you turn this topic into a science project? What resources would you need?
© Royal Observatory Greenwich