Solar system evolution

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I think it's interesting that Uranus is in first density and has the potential to move through all densities, they are next in line it seems.

I found that part interesting as well. I thought that perhaps third-density on Uranus would happen when our sun had grown a considerable degree towards being a red giant. Maybe then the sun would reach closer to the planet, but who knows? It seems so inhospitable at this stage, but I guess that's the beauty of first-density evolution.

That's an interesting point. Uranus is way outside the habitable zone in our solar system so conditions would have to be very different for it to host life (as we know it at least).