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Degenerate bodies obviously have gravity far beyond what any normal matter body has. I'm interested only in places where you can have normal matter, even if the environment is otherwise extreme.

Looking at the solar system we have 28g at the surface of the sun, the gravity obviously increases as you descent through the outer layers, but eventually you'll be below enough mass that it will decline as you go deeper. My gut says to look below the surface of a big O star that's at the Eddington limit, but I don't know enough to be confident in this, or any idea of how much gravity there will be.

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  • $\begingroup$ What exactly is "normal" matter? $\endgroup$
    – L.Dutch
    Commented Jul 21, 2022 at 15:50
  • $\begingroup$ @L.Dutch Non-degenerate. Not a white dwarf, not a neutron star, not a hypothetical quark star, not a black hole. $\endgroup$ Commented Jul 21, 2022 at 15:52

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Give you explicitly eliminate neutron stars (which have at most only a thin crust of even degenerate matter) and white dwarves (which are mostly degenerate matter), you'd want the largest mass of the coldest material that's too lightweight to crush electrons into their nuclei.

This is probably several times the mass of Jupiter.

"But the Sun?!" If you cool the Sun enough to have a solid surface to stand on, the core will crush into degenerate matter (this is essentially what happens after a star too light to become a supernova collapses from its red giant stage). I recall reading that there may even be a small degenerate core in some brown dwarves -- simply because there isn't enough mass to produce sustained fusion in the core, so there isn't additional heat or radiation pressure to support the upper layers.

Now, if you're okay trying to survive temperatures above the boiling points of nearly all materials, and pressures in Gigapascals, then yes, you could go diving into the envelopes of O supergiants. Good luck with that...

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    $\begingroup$ I doubt gigapascals are a big enough unit. $\endgroup$ Commented Jul 21, 2022 at 15:59
  • $\begingroup$ @LorenPechtel You're probably right, but they're enough to produce metallic hydrogen in gas giant planetary cores. I doubt you could construct a gravimeter from any material that would survive both the temperature and the pressure down there... $\endgroup$
    – Zeiss Ikon
    Commented Jul 22, 2022 at 11:15

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