asakiyume: (squirrel eye star)
[personal profile] asakiyume
Your poem reminded me about some thoughts I'd been having re: weight/mass and gravity, [personal profile] amaebi!

If you imagine something the size of a baseball, but that you are unable to pick up because it's so heavy, then that item is going to affect the ground it's on more/differently than a baseball would. If the ground is soft, the uncannily heavy ball is going to sink into it more, right? And if it were so heavy that an earthmover couldn't lift it up, it would--under normal physics--probably sink deep into the ground, right? Because an earth mover could scoop up **underneath** it otherwise--and the only way that wouldn't work would be if the thing were at the bottom--which it would be, if it were heavier/more massy than stuff around it... right?

So if you want to have an item that can't be lifted, but **doesn't** deform the land around it in this way, then normal physics aren't in operation.

... Is that correct?

Date: 2018-02-09 03:05 pm (UTC)
larryhammer: a low-fidelity picture of a man, label: "some guy" (Default)
From: [personal profile] larryhammer
The strength of something is not the same as its mass. The dirt under the superheavy ball can be capable of holding it up without being heavier than it.

It likely, under ordinary physics, will get heavily compressed, and the superball sink down somewhat. But it won't necessarily sink deeply -- the dirt can compress only so much.

Date: 2018-02-09 03:46 pm (UTC)
larryhammer: a low-fidelity picture of a man, label: "some guy" (Default)
From: [personal profile] larryhammer
I can see two possibilities: the soil under the heavyball might be so densely compacted the earthmover can't push its blade through it; if it can, at that point, then it simply wouldn't be able to lift it.
Edited Date: 2018-02-09 03:47 pm (UTC)

Date: 2018-02-10 05:35 pm (UTC)
marycatelli: (Default)
From: [personal profile] marycatelli
No, not through it, probably. If it were that dense, it would fly straight through the earth and start oscillating up and down, just as a basketball would do on a planet of pure air.

Date: 2018-02-10 07:04 pm (UTC)
marycatelli: (Default)
From: [personal profile] marycatelli
Well, if it were in a very early universe when not much beyond hydrogen and helium existed. . . .

If not, that's still what a basketball would do it in.

Date: 2018-02-09 09:02 pm (UTC)
noachoc: (Default)
From: [personal profile] noachoc
Tangential, but I've always wanted to try to pick up a gold brick.

Date: 2018-02-10 05:29 am (UTC)
From: [personal profile] khiemtran
Every action has an equal and opposite reaction. So, if the ground is exerting enough force on the ball to hold it up, then the ball is pressing down into the ground with the same force. Normally, that would be enough to deform the surface, and hence the ball would be pressed into the ground.

Note that equal and opposite reactions also apply to someone trying to lift the object. So, if you were trying to lift the ball upwards, you would feel your feet pressing into the earth downwards. An earthmover that scooped underneath the object, would likewise find itself pressing into the ground as it tried to lift it. Because it has a wider surface area than a baseball, you would expect that it wouldn't deform the earth as much as the ball did (under normal physics).

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