Jupiter
Jupiter is the fifth planet from the Sun, the largest and oldest planet in the solar system, and more than twice as massive as all the other planets combined. Its hydrogen-helium atmosphere is banded by jet streams thousands of kilometres deep, its Great Red Spot has been observed for centuries, and its magnetosphere is the largest structure in the solar system. Juno has been orbiting Jupiter since 2016, ESA's Juice is on its way for a 2031 arrival, and NASA's Europa Clipper will reach the Jovian system in 2030 to study the icy moon Europa.