[/caption]Jupiter is a gas giant composed of a bout 90% hydrogen and 9.99% helium with a few other trace elements thrown in for fun. The gaseous nature of the planet makes a solid surface impossible. So, scientists devised a way to define the surface of Jupiter. The surface of the planet is defined as the point where the pressure of the atmosphere is 1 bar, which is equal to the atmospheric pressure at Earth’s surface.
This is happens to be the point at the bottom of Jupiter’s atmosphere where its upper clouds of ammonia ice are visible. If a spacecraft were to descend farther, it would encounter thicker clouds of ammonia, eventually reaching clouds of water vapor. Below the water vapor there is only ever thicker mixtures of hydrogen and helium until the craft hits the core. Scientists theorize that the center of Jupiter is a dense core of liquid metallic hydrogen with some helium with a temperature in the neighborhood of 36,000 Kelvin. There really isn’t any possible place to land a spacecraft on Jupiter.
It would be very difficult for a spacecraft to descend to or below the surface of Jupiter. The planet’s atmosphere is particularly harsh. Jupiter is perpetually covered with clouds composed of ammonia crystals and some may contain ammonium hydrosulfide. The clouds are located in the tropopause and are sub-divided into light-hued zones and dark belts. These conflicting patterns cause horrifically strong storms. Wind speeds in excess of360 km/h are common. The entire atmosphere is constantly charged with excited particles spewing from the volcanoes on the moon Io. Lightening is ever present in portions of the atmosphere, as well. Then there is the tremendous atmospheric pressure. Just a few km below the recognized surface of the planet, any spacecraft would be crushed by pressures topping the Earth’s by more than 1000%
Jupiter is not the only planet facing debate as to whether it has a surface or not. Scientists debate the pint about all of the gas giants. One model suggests that ll planets had to evolve from the solar nebula with a rocky in order to accrete their mass. The gas giants are believed to have evolved very early and were, therefore able to accumulate the lightest gases like hydrogen and helium. The model goes on to say that the core and rocky surface of Jupiter simply moved by convection into the atmosphere and on back into space, thus explaining why there currently is no surface of Jupiter to land on.
We have written many articles about Jupiter for Universe Today. Here’s an article that proposes that Jupiter might actually have a rocky core, and here’s the best ground image ever captured of Jupiter.
We have recorded a podcast just about Jupiter for Astronomy Cast. Click here and listen to Episode 56: Jupiter.