An artist's impression of the Galileo probe descending into Jupiter's atmosphere. The probe was the first to sample the atmosphere of a gas planet. It measured temperature, pressure, chemical composition, cloud characteristics, sunlight and energy internal to the planet, and lightning. During its 58-minute life, the probe penetrated 200 km (124 miles) into Jupiter's violent atmosphere before it was crushed, melted, and/or vaporized by the pressure and temperature of the atmosphere.