If you have a pair of binoculars or a small telescope look at Jupiter and see if you can make out the small dots of light surrounding Jupiter. These are the four largest moons of Jupiter, known as the Gallilean moons after Gallileo who was the first person to see them. Gallileo was the first person to use a telescope to observe the night sky. The binoculars or telescope you are using is almost certainly more powerful that the one he used to discover the moons of Jupiter!
In a small telescope they will look something like the image below (three moons are visible in a line in this image).
The moons move around Jupiter every few days so sometimes they are hidden by the planet or each other. So don't be surprised if you can't see all four.
Can you find out the names of each moon and how long they each take to orbit Jupiter?
