How might Titan become more like earth?

Answer 1

Possibly when The Sun swells to a Red Giant in 5 billion years time. It's surface temperature of -180 Celsius needs to be well above 0 Celsius for liquid water exist in three states (gas/liquid/solid) like on earth. It is unknown exactly how much Titan could warm up on average during the RG phase of the sun (it could vary from antarctic winter to a hot day in Death Valley/Sahara) but it's likely to be far more hospitable than the inner rocky planets. It's methane-rich world could be replaced by more water vapour in it's atmosphere when it evaporates from ice sheets into the atmosphere and falls as rain (albeit more slowly like snowflakes) and replaces the methane lakes. Most of the methane present would become mostly gas and less will exist as liquid and solid. It is unknown however how long it'll take for methane to replaced by water or whether another chemical will take it's role with a higher boiling point (e.g ethane/ethanol). If it does resemble earth in composition in the air and oceans like today in the distant future, due to it's smaller size and weaker gravitational pull, it will be short lived and may suffer the same fate like Mars possibly due to losing it's magnetosphere and been stripped of it's thick atmosphere by the solar wind (which may be significantly stronger in RG stage which could limit Titan's potential as the 'next earth'.