How big is the Milky Way?

The Milky Way has a diameter of approximately 100,000 light years, meaning that it would take that long to travel from one end to the next. However, our solar system – comprising the Sun, its orbiting planets, comets, asteroids and all kinds of other space bodies – doesn’t have a clear boundary. But if you use the orbit of the furthest known objects – the cloud of comets called the Oort Cloud (much farther from the Sun than Pluto) – it’s about two light years. That gives you an idea of how small our solar system is in comparison to the Milky Way as a whole.

Answered by Shanna Freeman, How It Works contributor.