In the cores of the gas giants, temperatures may be in the tens of thousands of degrees, with pressures of tens of megabars. (Recall that a pressure of 1 bar corresponds closely to Earth’s atmospheric pressure at sea level. A megabar is a million times as great as 1 bar.) For comparison, when the submersible research vessel Alvin cruises Earth’s ocean bottoms 10,000 meters below the surface, it experiences a surrounding pressure of about 1,000 bars, or 1/1,000 of a megabar. Water is still liquid in the cores of the giant planets, at temperatures of tens of thousands of degrees. As in a super pressure cooker, the extremely high pressures at the centers of the giant planets prevent the water from turning to steam. The temperature at Jupiter’s center is thought to be as high as 35,000 K, and the pressure may reach 45 megabars. Central temperatures and pressures of the other, less massive giant planets are correspondingly lower than those of Jupiter.