Original Title: How the Universe Works
A users' guide to the cosmos, from the Big Bang to galaxies, stars, planets and moons: where did it all come from and how does it all fit together? A primer for anyone who has ever looked up at the night sky and wondered.
From the furthest reaches of space to our own cosmic backyard, we count down the discoveries that changed everything we know about our universe.
Examining a ninth planet that may be on the outer edge of the solar system. Scientists speculate that it could be 10 times the size of Earth and have moons capable of hosting life.