Moon and Jupiter 
Jupiter is the largest planet in the solar system, and twice as massive as all the others put together. But new calculations suggest the mighty planet has a problem: its heart is dissolving.
Jupiter is classified as a gas giant, which means it consists mostly of hydrogen and helium. Jupiter’s enormous gravity, though, squeezes most of its hydrogen into a metallic fluid that conducts electricity. It wraps around a small, rocky core.
Planetary scientists at the University of California at Berkeley recently calculated what could happen to that rocky core under the extreme conditions at Jupiter’s heart, which is hotter than the surface of the Sun and has a pressure 40 million times that of Earth’s atmosphere. The calculations indicate that the rock dissolves into liquid, so Jupiter’s core could be slowly eroding.
Conditions are even more extreme at the centers of the even heavier planets found orbiting other stars. So gas giant planets that weigh several times more than Jupiter may have already destroyed their cores.
Scientists hope to get a better look at Jupiter beginning in 2016, when the Juno spacecraft enters orbit around the planet. By measuring the planet’s gravity field, Juno will provide new details on conditions in the giant planet’s heart.
Jupiter is quite low in the west at sunset this evening. But the brilliant planet is still fairly easy to find because it lines up directly below the crescent Moon as the sky grows dark.
Script by Ken Croswell, Copyright 2012