GCSE Astronomy

What is a light year?





Distances in Space

Distances to objects in space are very, very large. The nearest star (excluding the Sun), Alpha Centauri, is 41.23 trillion km, or 41,320,000,000,000 km!!



a starry background with a tape measure and the word year


What is a star?

We can see thousands of stars in the night sky - small points of light in the vastness of space. But what are stars? How do they make light? Why are they different colours? Watch this video to find out some more information about stars!



A photo of the Sun with the text What is a star? on a black background


What is a nebula?



Images of nebulae in space with a question mark in the centre


Investigate: Measure the Size of a Galaxy

Have you ever wondered how big a galaxy is? They contain millions to billions of stars but what does that really mean for size?

Reading about sizes in a book is one thing, but what if you could make an observation of a galaxy and then measure its size?



Picture of a galaxy with a ruler next to it and question marks


What is the Sun?





Make Your Own Star Wheel

Have you ever noticed how the night sky looks different every single day? This is because we are constantly moving in space so our view changes.



A picture of a starry sky with question marks over the top


Planet Facts Posters

Do you know how many planets in our Solar System have rings? Or how many have moons? Learn some interesting facts about the planets in our Solar System with these free printable posters!



Thumbnail of the 8 Planet Facts Posters


Lunar Libration

A video of lunar libration made by taking photos night after night for a month, showing a wobbleThe Moon is locked with the Earth, which means that we always see the same side of the Moon. You would think that this meant that we could only see 50% of the Moon's surface, but we can see slightly more from Earth.


Our Sun Quiz

Short Intro Text: 

The Sun is our closest star and the centre of our Solar System. However, it is only one of several billion stars in our galaxy.

Astronomers study and learn about the Sun using observations from telescopes along with data collected by space probes. But how much do you know about our star? Test your knowledge using this quiz!





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