Teamwork

Galaxies are collections of millions, or billions of stars. The Milky Way is the galaxy in which we live, orbiting around it’s centre in a distant spiral arm.

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?

From our viewpoint on Earth, we are the centre of a huge sphere in space. And all the objects in the night sky appear as points on the sphere.

Einstein showed that the speed of light is a universal constant. This means that it always travels at the same speed in a vacuum.