Now that we’ve finished our tour of the planets, we’re headed back to the asteroid belt. Asteroids are chunks of rock, metal, or both that were once part of smallish planets but were destroyed after collisions. Most orbit the Sun between Mars and Jupiter, but some get near the Earth. The biggest, Ceres is far smaller than the Moon but still big enough to be round and have undergone differentiation.
Professor Brian Cox explores the powerhouse of them all, the sun. In India he witnesses a total solar eclipse and in Norway, he watches the battle between the sun's wind and Earth, as the night sky glows with the northern lights. Beyond earth, the solar wind continues, creating dazzling aurora on other planets.