These planets, like Jupiter and Saturn in our solar system, don’t have hard surfaces and instead have swirling gases above a solid core. Gas giant exoplanets can be much larger than Jupiter, and much closer to their stars than anything found in our solar system.
As a gas giant, Jupiter doesn’t have a true surface. The planet is mostly swirling gases and liquids. While a spacecraft would have nowhere to land on Jupiter, it wouldn’t be able to fly through unscathed either.
Their atmospheres vary in density from Mercury’s extremely thin atmosphere to Venus’, which is thick with clouds of sulfuric acid. The four planets that are more distant from the sun—Jupiter, Saturn, Uranus, and Neptune—are called gas giants. Gas giants are huge compared with Earth, and they do not have solid surfaces.
The planets Mercury, Venus, Earth, and Mars, are called terrestrial because they have a compact, rocky surface like Earth’s terra firma. The terrestrial planets are the four innermost planets in the solar system.
Jupiter is made up almost entirely of hydrogen and helium, with some other trace gases. There is no firm surface on Jupiter, so if you tried to stand on the planet, you sink down and be crushed by the intense pressure inside the planet.
Surface. As a gas giant, Saturn doesn’t have a true surface. The planet is mostly swirling gases and liquids deeper down. While a spacecraft would have nowhere to land on Saturn, it wouldn’t be able to fly through unscathed either.
But in the dense atmospheres of planets like Jupiter and Saturn, whose massive size generates enormous amounts of gravity, crazy amounts of pressure and heat can squeeze carbon in mid-air — and make it rain diamonds.
The density and temperature changes the deeper into the planet you go, but Saturn can’t be said to have a solid surface. If you tried to walk on the surface of Saturn, you would fall into the planet, suffering higher temperatures and pressures until you were crushed inside the planet.
If a person wanted to actually walk on the surface of Pluto, the astronaut would probably need to add a significant amount of weight to his gear in order to keep his feet firmly enough on the surface of the planet to actually walk around.
First, getting there: “You essentially need three rockets to get to Mercury,” Hauck said: one to get off Earth, one to get from Earth to Mercury and one to carefully land on the planet (because it lacks an atmosphere that can slow down a spacecraft).
The cores of the gas giants are crushed under tremendously high pressures and they are very hot (up to 20,000 K), while the cores of the ice giants Uranus and Neptune are at 5000K and 5,400K respectively. Gas giants have been found around more than a thousand stars by the Kepler mission.
The layer of metallic hydrogen located in the mid-interior makes up the bulk of every gas giant, and is referred to as “metallic” because the very large atmospheric pressure turns hydrogen into an electrical conductor.
No, Jupiter doesn’t have a solid surface. It is the largest among planets but lacks a firm solid surface. If one tries to paraglide and land on the surface of Jupiter, he would fail to find a surface and would rather slide down through layers of gas, dust, vapor, and liquid and finally reach the hot core.
All known gas giants, like Jupiter and Saturn, have solid cores. These cores are either rocky or metallic, and aren’t completely solid throughout, with some of the core being comprised of molten metal and rock.
It has about the size of Earth and 5-15 times its mass. So if all of Jupiter’s gas went away the liquid core would remain as an ocean planet. An ocean of liquid metal and the remnant core having a surface gravity of 5-15 g. The Galilean moons would get ejected into a solar orbit.
To travel the billions of miles between Earth and Pluto, the amount of fuel you would have to bring with you isn’t a major problem for New Horizons, but for a manned mission, it would be prohibitive. Chemical fuels are heavy and you eventually hit a limit on how much mass a rocket can lift off the planet.
