How do we find asteroids?

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?

The Sun is a constant presence in our life on Earth. It gives us the heat and light we need to survive. But it is not a stable place. The Sun is a ball of hot plasma which is constantly changing.