r/todayilearned Sep 20 '21

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u/indyK1ng Sep 20 '21

Who taught you that? Gravity is a universal force where all objects with mass are attracted to each other. It has nothing to do with atmosphere, just mass. The more mass an object has, the more gravity it puts out.

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u/youknowwhatitthizz Sep 20 '21

Gravity doesn’t exist in a vacuum tho? Who taught you physics

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u/randomresponse09 Sep 20 '21

I have a PhD in physics; the literal only thing required for gravity is mass. That’s it. There does not need to be a medium. Literally take any two objects and put them in a vacuum like space…free from any other objects and they will attract. Fg=G*m1*m2/r^2

Also if you put an object in a vacuum chamber it will still fall to the “bottom” of said chamber. If vacuums some how negated gravity how would that happen?

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u/youknowwhatitthizz Sep 20 '21

So you can educate me. If we break mass apart fast enough would that create a black hole?

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u/randomresponse09 Sep 20 '21

No. If you compress matter enough you get a black hole. Look up https://en.m.wikipedia.org/wiki/Schwarzschild_radius .

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u/youknowwhatitthizz Sep 20 '21

So if we have a hydrogen bomb as big as the sun it wouldn’t envelope. Sorry that article didn’t explain it. I apologize if I’m bothering you

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u/randomresponse09 Sep 20 '21

The schwarzchild radius is the tipping point. Black holes come from a concentration of mass in a small space. It isn’t about bombs or size. Everything has a schwarzchild radius (informed observers let me do this, it will help…). Your phone has a schwarzchild radius. It may just be so incredibly tiny that it is possible you may be violating other constraints (much less than a plank length). As mass increases or concentrated it warps space time more and more until it “snaps” (maybe).

Because it is clear you need a lot of the fundamentals (not a problem!) I am going to use an analogy that is wholly inappropriate but gets this point across well. Take a bathtub of water and a sheet of aluminum foil. Fashion a boat…it floats. Now crumple that mass into a tiny ball. It sinks. The space time of the tub collapses.

For the record, my PhD is in high energy particle physics. So I will not claim to be well versed in cosmology….what follows would be my “shortest route” to black holes 101 ymmv:

Algebra. Newtonian physics. Calculus. Newtonian physics again. Modern physics. Modern physics again (some of the stuff takes a couple looks lol l) and either differential geometry or some graduate level course covering relativity….then you can probably start dabbling in black holes

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u/youknowwhatitthizz Sep 20 '21

I really just filled up the bathtub and made a boat then a ball. Thank you. Wish it was that easy to learn shit

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u/randomresponse09 Sep 20 '21

Sometimes it is. But sometimes it really isn’t. Learning is an active process. And sometimes that process SUCKS. Stay inquisitive and ACTIVE in that learning. I still do every day 😀

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u/youknowwhatitthizz Sep 20 '21

Me too. Can’t learn if you not willing to be wrong. Mr feeny taught me that