Planets collapsing into black holes?

AI Thread Summary
A hypothetical scenario discusses a planet with Earth's mass and radius but with a gravity constant 500 million times larger, leading to a significantly increased Schwarzschild radius. This change would likely cause the planet to collapse immediately due to the immense gravitational pull. The discussion also clarifies the relationship between GM/c² and 2GM/c², noting that GM/c² represents a gravitational radius, which is half the size of the Schwarzschild radius. The concept of adjusting the gravitational constant is acknowledged as unfeasible, but it serves to illustrate the theoretical implications of extreme gravity. Overall, the conversation explores the conditions under which a planet could collapse into a black hole.
Lamdbaenergy
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If you had a planet with the exact same mass and radius as the Earth, and adjusted the gravity constant to some value five-hundred million times larger, the schwarzschild radius should become considerably big, right? Instead of being about 8 millimeters, it would now be about 60 to 70 percent the radius of the body itself. So would this cause the planet to start collapsing immediately, and just how strong would the gravity have to be to cause the surface of the planet to start falling in on itself?
Also, what does GM/c2 mean compared to 2GM/c2?

I totally know that changing the gravity constant is impossible, let alone to that ridiculously high value.
 
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Yes, if you plug in a different and unphysical value for G, you get a different and unphysical value for R.

Lamdbaenergy said:
Also, what does GM/c2 mean compared to 2GM/c2?

It's half as big. (I think we're missing some context here)
 
Vanadium 50 said:
Yes, if you plug in a different and unphysical value for G, you get a different and unphysical value for R.
It's half as big. (I think we're missing some context here)

Why does the schwarzschild radius have to be twice as big as GM/c2? Is GM/c2 another special kind of radius that is always half the length of the schwarzschild radius? Thanks.
 
I don't think there is anything special about the 2.
 
Never mind the GM/c2 part. I found out that it is called a gravitational radius and it is half as large as the black hole.
 
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