I believe on Titan they have lakes and rivers of liquid methane, but no oxygen. So the liquid fossil fuels are not combustible.
Good list. I’d add condensation of liquid from the atmosphere (dew) and deposition of solid from the atmosphere (frost).
Plasma <-> gas happens in the Earth’s upper atmosphere (ionosphere).
I think if we generalize things this far (which I think is OP’s intent), and we include the upper atmosphere of the Earth, then the Earth has an equivalent of every possible weather. We have tidal effects. Reduction is just oxidation from a different perspective. And you can find places on Earth where liquid boils into the atmosphere (e.g. Yellowstone).
With respect, that’s because you are marinated in this stuff. While I don’t find the result to be intellectually surprising, I did nonetheless receive a charge from those articles. Amazed.
There are things that specialists sort of expect. Non-specialists don’t form such expectations, because they don’t think as much about them. Plus we don’t have the same sense of relative certainty regarding different expectations. Flatter Bayesian priors produce more surprises.
When it comes to planetary science I’m barely more than a slightly educated enthusiast. I suspect that as our ability to detect and hopefully even image extrasolar planets, we are going to find things that would give Slartibartfast the willies.
Stranger
I hear that NASA is designing a space telescope capable of resolving fjords up to 80 light years away.
Note that the first extrasolar moon ever detected is absolutely not a typical moon. A weird monster moon like that, we can detect. A normal moon, we can’t. So it’s no surprise that the moon we detect is a weird monster one.
What we seem to have here is a large gas giant (approximately 10 times as massive as Jupiter) with a smaller object (about as large as Neptune) in orbit around it. This pairing sounds more like a double planet rather than a planet with a conventional gas giant moon around it.
Double planets of this kind probably form when one planet captures another - this doesn’t seem to be that unusual, since the Earth/Moon and Pluto/Chiron systems both seem to have formed through capture. A big gas giant capturing a little gas giant would be a spectacular sight, I think. There would have to be some mechanism to remove some of the momentum from one, or both of the planets concerned.
Just seeing those two objects as a system would be awesome in itself, as there would be a stream of gas flowing between them. A sufficiently large satellite might shed enough mass onto the primary to bring it to brown dwarf mass. If the two are orbiting a red dwarf near the GZ and the satellite is the appropriate metallicity, it might eventually reduce to a habitable body (with the brown dwarf distorting the bounds of the GZ). The weather on the moon would be quite interesting to speculate on.
There isn’t a clear technical distinction between planet-moon and doublet, but while Luna is about 1% of the mass of the Earth, Charon is about 12% of the mass of Pluto. A Neptune-sized “moon” orbiting a supergiant planet with ten times the mass of Jupiter would be about 0.5% the mass of its primary, and unless it orbited at an extreme distance the barycenter would be within the diameter of the primary which is the typical (if not particularly rigorous) distinction between a planet-moon and doublet system.
More important than the present characteristics of the system, though, is how it formed. With Pluto-Charon and its extended set of moonlets, it likely occurred due to some chaotic capture by the influence of Neptune, or else they were actually moons of Neptune that were ejected together, all having original come from the Kuiper belt. Earth-Luna is very different because there is virtually no way a simple capture could have occurred without the close influence of another body, hence the dominant theory that the Moon is the result of an impact on the primordial Earth by some larger object that struck and caused a large mass of material to be ejected.
I’m not sure there is even a working theory for the capture of an icy giant by a supermassive gas giant. The impact mechanism probably isn’t workable because of the way giant planets form, so it seems likely that there is some other mechanism, but without more details about the composition of the planets it is barely even guesswork.
And Chronos is correct; the moons, and for that matter, the planets that we observe around other stars do not represent a typical distribution because our ability to detect and image planets is very limited, so we can only detect specific configurations and generally larger planets (though with the transit method around dim main sequence stars it is possible to detect planets that are as small as Mars or potentially even smaller). So we do not see a standard distribution, but rather specific slices of the overall population that are most amenable to detection. We therefore need to be aware of what may exist that we cannot observe (yet). That was actually the whole purpose of the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) observatories that discovered the TRAPPIST-1 system with seven planets in sizes ranging in diameter from about that of Venus to slight more than Earth. The early pop-science claims that they were actually “Earth-like” were incorrect although -c and -e are close to Earth gravity and density; all are probably tidally locked or in spin-orbit resonance, and if liquid water exists it is due to tidal heating that likely produces Io-like seismic activity.
Stranger
The OP was looking for exotic weather; it seems to me that a planet warmed by tidal heating is pretty exotic. Worlds that should be frozen are heated by the action of tides so much that they are warm enough to hold liquid water. The fact that this warming is accompanied by continual volcanic activity is a disadvantage, of course.
That depends on what you mean by a “normal moon”. We could detect a roughly Luna-sized moon (of which there are 7 in the Solar System) in another star system, although it may depend on the mass of the planet it orbits. Even if we can’t detect the moon via the transit method, it’ll change the timing of the planet’s transit. The smaller the mass of the planet, the bigger the effect and the easier it would be. In fact, one of the pieces of evidence for that monster moon is that a transit ocurred 78 minutes earlier than expected.