Hello everyone, I have a theoretical question about an animation in the documentary I’ve linked in this post.

At timestamp 05:01, you can see an animation of Venus, suffering the effects of a change in gravitational forces. After being close enough to the expanding sun, Venus begins to lose material on its surface due to the stronger gravitational pull of the sun.

For me, this whole animation doesn’t seem right because the mass and the center of mass of the sun doesn’t change. I can imagine how the mater of the sun’s surface could change the gravitational pull that the material on Venus’ surface is experiencing, but would it be that strong at that point? I would’ve assumed that more and more of the sun’s mass will be concentrated in the core as the red giant is expanding and not leaving enough mater to overcome Venus’ gravity at its surface.

Once, Venus enters the denser parts of the suns’ atmosphere, I wouldn’t doubt that the atmospheric drag or the fall towards the denser core would scatter the material on the surface and eventually destroy Venus completely. Shortly before that, however, while Venus is still roughly maintaining an orbit similar to its current one, this doesn’t seem right to me.

Did they mess up this animation or will the sun, at its surface, have more gravitational pull than Venus?

  • Jeredin
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    10 months ago

    Do not that this video seriously as to what it will likely look like. Keep in mind that as our sun grows into a red giant it would already be releasing extremely lethal solar flares. The inner planets being consumed by the sun would only come long, long after cooking them. Gravity would also be interesting at this point because the sun would have less mass. This video seems to take a lot of liberties as to how the physics of transitioning into a red giant would play out.