I'm interested in what kind of events / processes would it take to make Titan's atmosphere more or less transparent.
The year is around 2150. The technology has progressed, sure, but it's nowhere near the point where people could toss around planets between orbits, or terraform them as they wish in a matter of years. This change, however, may be due to some unintended runaway reaction.
I'm aware of this question, which may seem similar but asks about constructing a new planet, rather than changing the Titan itself.
The accepted answer on that question also mentions more useful details:
The orange color as seen from space must be produced by other more complex chemicals in small quantities, possibly tholins, tar-like organic precipitates. The hydrocarbons are thought to form in Titan's upper atmosphere in reactions resulting from the breakup of methane by the Sun's ultraviolet light, producing a thick orange smog.
With that in mind, here are requirements for the solution I'm looking for:
- Transparent means enough to see the Sun and Saturn through. Stars aren't necessary, but more is better.
- Clouds or some amount of haze are okay, as long as first point is true.
- Atmosphere doesn't need to be stable in this state. Over time, it can dissipate, become colder or hotter, revert back to original state. I want it to maintain some kind of transparency for 3-5 years.
- The resulting makeup of atmosphere doesn't matter either, as long as it lets through enough visible light.
- Since the Sun and the Saturn are mentioned, it shouldn't require their total destruction.
- Earth and Mars shouldn't be made completely uninhabitable (as in Venus uninhabitable, or worse).
The solution doesn't need very hard-scienc-ey. It's alright to go for improbable, yet theoretically possible scenarios, and to resort to some assumptions about minute details of such process. What I want here is to avoid full-on handwaving away using some amazing unearthed alien artifacts, or just a completely unexplained change.