In the infrared images taken by the New Horizons spacecraft in 2007, Jupiter's highest-altitude clouds appear blue, its lower cloud tops are red, and its famous Great Red Spot here looks blue-white. While space agencies are planning to send more orbiters to study Jupiter and its moons in the next decade, probes remain impractical because the gas planet has no solid surface to land on. The single probe released into its atmosphere, in 1995, was crushed by the pressure and heat after 57 minutes of descent.
On the right is Io, one of Jupiter's four giant moons. What appears as a blue bulge on its top is actually a colossal gout of incandescent sulfurous material spouting from the northern volcano Tvashtar.