Is there another Earth out there with liquid oceans, rocky continents and life like us? Astronomers seek the answer with spectroscopy, direct imaging and telescopes. They hope to find evidence of atmospheres, magnetospheres and signs of life.
Before moving on from Jupiter to Saturn, we’re going to linger for a moment on Jupiter’s moons. There are 67 known moons, and 4 huge ones that we want to explore in greater detail. Ganymede is the largest - larger, in fact, than any other moon in the solar system and the planet Mercury! Callisto, orbiting the farthest out, is smaller but quite similar to Ganymede in many ways. Io, meanwhile, is most noteworthy for its tremendous volcanic activity. There’s also water on Ganymede and Europa!
The worlds that surround our planet are all made of rock, but there the similarity ends. Some have a beating geological heart, others are frozen in time. Professor Brian Cox travels to the tallest mountain on Earth, the volcano Mauna Kea on Hawaii, to show how something as basic as a planet's size can make the difference between life and death.
Ultra-sensitive telescopes have transformed alien planet-hunting from science fiction into enthralling hard fact. Join NOVA on a visit to exotic worlds orbiting distant suns to answer an age-old question with thrilling new science: are we alone?