Venus was habitable (with vast oceans, plate tectonics, soil and everything) for 3 billion years (almost 70% of its history!), until about 700 million years ago... it stopped being habitable because of Jupiter.

From Wikipedia:

Between 700 and 750 million years ago, a near-global resurfacing event triggered the release of carbon dioxide from rock on the planet, which transformed its climate. In addition, according to a study from researchers at the University of California, Riverside, Venus would be able to support life if Jupiter had not altered its orbit around the Sun.

Considering there's a good chance Jupiter obliterated our next door neighbours, an entire planet of organisms... yea it's not as nice as it seems

Oh well. Mars was also habitable for a few hundred million years – in fact, the river beds and remnants of the Martian oceans are still very clearly visible on 2/3 of the surface, even after 4 billion years, and NASA is on a mission to bring fossils of ancient Martian life back to Earth, if there are any. But all of its atmosphere leaked out into space because its dynamo (magnetic field generation) abruptly disappeared so... skill issue lol. One of the many possible contributing factors to that happening is that giant impacts during that period of time overheated its mantle which fucked up global heat flow & convection near the core so... Jupiter's fault again?

Me when i spread misinformation

mammals

Siblings, amirite?