In gratitude to the many readers who have sent in pointers to this item, and in ongoing appreciation of the living national treasure that is Randall Munroe of xkcd, and as a little pre-Superbowl feature, here is a look at Munroe's latest "What If?" feature. In this installment, "Interplanetary Cessna," he asks how a small aircraft would fare on different bodies in and around the solar system. Sample visual aid:
Sample explanations, based on flight-simulator experiments:
The Sun: This works about as well as you'd imagine. If the plane is released close enough to the Sun to feel its atmosphere at all, it's vaporized in less than a second....
Jupiter: Our Cessna can't fly on Jupiter; the gravity is just too strong.... Starting from a friendly sea-level pressure, we'd accelerate through the tumbling winds into a 275 m/s (600 mph) downward glide deeper and deeper through the layers of ammonia ice and water ice until we and the aircraft were crushed. There's no surface to hit; Jupiter transitions smoothly from gas to solid as you sink deeper and deeper....
Uranus: Uranus is a strange, uniform bluish orb. There are high winds and it's bitterly cold. It's the friendliest of the gas giants to our Cessna, and you could probably fly for a little while. But given that it seems to be an almost completely featureless planet, why would you want to?
Neptune: If you're going to fly around one of the ice giants, Neptune (Motto: "The Slightly Bluer One") is probably a better choice than Uranus. It at least has some clouds to look at before you freeze to death or break apart from the turbulence.
(And, yes, I know -- except that in most of these places the atmosphere is too thin for the parachute to do any good. Still. Congrats and thanks to Munroe and his readers.)