It’s not density, it’s mass. A mass of 1kg compressed to the density of the Sun’s core would pull the Earth with just as much force as a 1kg ball of styrofoam.
Xkcd did a what if on a black hole moon (getting it to collapse into one may be impossible, but a black hole the mass of the moon is theoretically stable), and it has the same conclusion, except just slightly colder instead of slightly frozen. And by slightly, I mean almost imperceptible.
Just to add some formality to this, the original commenter might want to look up the shell theorem for classical mechanics and Birkhoff’s theorem for general relativity.
It’s not density, it’s mass. A mass of 1kg compressed to the density of the Sun’s core would pull the Earth with just as much force as a 1kg ball of styrofoam.
And is the Sun was replaced with a black hole of the same mass, the Earth would just keep on rotating around it without issues, if slightly frozen
Xkcd did a what if on a black hole moon (getting it to collapse into one may be impossible, but a black hole the mass of the moon is theoretically stable), and it has the same conclusion, except just slightly colder instead of slightly frozen. And by slightly, I mean almost imperceptible.
https://what-if.xkcd.com/129/
I mean, the Sun also contributes slightly more heat to the Earth compared to the Moon. And by slightly, I mean the difference between cold and frozen
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Just to add some formality to this, the original commenter might want to look up the shell theorem for classical mechanics and Birkhoff’s theorem for general relativity.