As we know, Venus had a runaway greenhouse effect that left it distinctly inhabitable for life as we know it. Perhaps, weirdly enough, Jupiter is to blame.
I’ll give this story to you quickly. Venus has a nearly perfectly circular orbit around our Sun, which is highly unusual. New models show that this orbit was not always the case and that Venus’ orbit was for more elliptical a billion years ago, while the planet was still possibly habitable. Where does Jupiter come into the story? Jupiter was closer to the Sun that same billion years ago, and it had to migrate out. As lead researcher Stephen Kane said: As Jupiter migrated, Venus would have gone through dramatic changes in climate, heating up then cooling off and increasingly losing its water into the atmosphere.
Habitability is not forever, it seems.
“Could the Migration of Jupiter Have Accelerated the Atmospheric Evolution
of Venus?,” Stephen R. Kane et al., 2020 September 4, The Planetary