Hubble takes a grand tour of the solar system

The NASA/ESA Hubble Space Telescope has completed its annual grand tour of the outer Solar System. This is the realm of the giant planets--Jupiter, Saturn, Uranus, and Neptune--extending as far as 30 times the distance between Earth and the Sun. Unlike the rocky terrestrial planets like Earth and Mars that huddle close to the Sun's warmth, these far-flung worlds are mostly composed of chilly gaseous soups of hydrogen, helium, ammonia, methane, and other trace gases around a packed, intensely hot...