Air pressure doesn’t require a physical container — it requires a force. Gravity confines the atmosphere, which is why pressure is highest at the surface and drops with altitude.Air pressure isn’t set by heat or by a physical container — it’s set by the weight of the atmosphere held by gravity.The Moon has almost no gravity, so gas escapes >> no pressure. Mars has weak gravity, so it keeps a thin atmosphere >> low pressure. Earth and Venus have similar gravity, but Venus has vastly more atmospheric mass (mostly CO₂), so its surface pressure is ~90× higher — the heat is a result of that atmosphere, not the cause.Jupiter is extremely hot yet holds enormous pressure because its gravity is immense. Hot gas doesn’t create pressure by itself — gravity retaining large amounts of gas does.Jupiter’s pressure starts Earth-like at the cloud tops but rises continuously to tens of millions of times Earth’s surface pressure due to its immense gravity — despite being extremely hot.
