system
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human
Is it possible to land something(a probe, a shuttle) on a gas giant like Jupiter?

I've a feeling this is an idiotic question, please bear with me. Since Jupiter is a gas giant, does that mean it has no surface to land something? For example the rovers on Mars, is it possible to land something similar on Jupiter/other gas planets? If not, what would happen?
gpt
There's likely a core that's solid, near the center of the planet...but otherwise no, there's not really a surface. No material we could possibly make on Earth could withstand the pressures and temperatures to land a spacecraft way down there.

There is quite a bit of *liquid* metallic hydrogen in Jupiter's interior. Our best estimates are that it starts somewhere about 30% of the way from the cloud-tops down towards the center, so it's really more the equivalent of Earth's mantle.

Now, inside of that, there may be a rock/ice core, estimated to weigh in anywhere between 5-30 Earth masses. For the accretion theory of planetary formation to work out, a proto-planet most likely needs about 5 Earth-masses of material before it can start sucking up gas in the protostellar disc to add to the mass of the planet. 

We think the accretion theory is most likely to be correct, so we expect there should be some kind of core left over from those days...but there may not be any core at all, either because 1) Jupiter formed by the gravity of the gas collapsing in on itself, or 2) the core has dissolved while immersed in all that metallic hydrogen (which is a very good solvent).

We'll know more for sure in 2016, when the Juno spacecraft is set to arrive at Jupiter. It will make a series of very tight, precise orbits around Jupiter. By watching how those orbits change over time, that will map out the gravitational field very carefully and tell us if there's a core hiding deep down there. 

So at the end of the day, nobody's gong to be sending a lander to Jupiter. We did send a probe into Jupiter from the Galileo spacecraft. It descended about 100 miles down to a pressure of ~22 atmospheres, at which point it stopped working. The probe material probably kept descending long after this, the metal eventually melting and dissolving into the surrounding mass. However, we could send a balloon to float around in the clouds, and sort of idea this idea gets people like me very excited.

**TL;DR**: There's likely a core deep, deep down, but not really a "surface" to speak of. We're better off floating a balloon in the atmosphere.