How does the amount of gas in an outer planet differ from the amount of gas in an inner planet?

Answer 1

As opposed to the rocky planets, which have a sharp demarcation between their rocky surface and gaseous atmosphere, the gas giants have no such distinction. Rather, they are made almost entirely of gases, some of which in their outer atmosphere may have frozen to the point of becoming particles of ices; but their core is (as far as current science can verify) made up entirely of gas under such extreme pressure that it has been turned into a liquid.

As such, gas giants have no actual surface as we would define it: just increasingly thicker and denser layers of the same elements and simple compounds that can be found in various concentrations inside their atmospheres.

As for exploring such extreme environments: the hostile and hellish surface of Venus is a paradise compared to what can be found just a few hundred miles down inside the atmosphere of Jupiter, where hydrogen itself has been compressed into a liquid metal a lot like the element Mercury here on Earth. We currently know of no material (real or theoretical) that could survive the trip, much less send back useful data.

Answer 2

Outer planets like Jupiter and Saturn have much more gas compared to inner planets like Earth and Mars. Outer planets are predominantly composed of hydrogen and helium, while inner planets have rocky surfaces with thinner atmospheres composed of gases like nitrogen and oxygen. The mass of gas in outer planets makes them significantly larger in size and more massive compared to inner planets.