Ecmandu, come at it from a different direction: Suppose you don’t know what’s inside the ball. You have two ball made of the same material. Let’s say the density of water is 1, so the first ball has mass X and volume Y such that X/Y = 1. The second has mass Z and volume Y such that Z/Y < 1. The second ball will rise, right?
That’s all that’s happening here. Replacing the center of the ball will with vacuum while maintaining the volume is just reducing the total mass of the ball without reducing the volume, so the density of the ball decreases. An air-filled ball rises because it has less mass per unit of volume, and the vacuum-filled ball just has yet less mass.
I think you’re right that in practice some of the material on the inside of the ball would sublimate into the vacuum, so it wouldn’t remain a pure vacuum; in practice a pure vacuum may not be possible on earth. Indeed, I don’t think a pure vacuum exists in space either, it’s an idealized concept. But we can and do create stable space-like vacuums on earth.
A pure vacuum cannot persist because it will be violated by quantum fluctations almost instantaneously
And as far as black holes are concerned they will have less mass over time because they will evaporate
Back to the original question : some answers on Quora claim that the determining factor is not vacuum but density
In a tank the ball will float if it has less density than the water surrounding it and it will sink if it has more density
And so two balls of equal density will behave in exactly the same way even if one does not have a vacuum in its centre and the other one does
Equally so two balls of equal vacuum but different density will not behave in exactly the same way especially if one has a higher density than
the water surrounding it and the other one has a lower density than the water surrounding it - so vacuum is not at all relevant in this scenario
Theres no such thing as a persistent absolute vacuum as quantum mechanics has demonstrated
So whatever is at the centre of a black hole is not absolute or infinite even if it is a singularity
For a singularity cannot contain infinite density because that is both logically and physically impossible
As a dead star with finite density cannot suddenly possess infinite density after it becomes a black hole
Aren’t those things, mass density and vacuum, opposites?
Gravity stems from having a high mass. A vacuum, having no mass, could not have gravity at all.
In general isn’t this an issue of average density of a given volume? Given a specific volume and considering that in one case the average density is that of pure water while in another case that same volume is mostly void of mass so with a lower average mass density, the one with the lower average density will get pushed away from the source of high gravity - the Earth (having tremendous mass in comparison).
The average density of a volume considers both the highest and the lowest mass (the water-weight shell and the vacuum together) to arrive at a medium density over all. It seems obvious that the rigid vacuum ball would rise even faster than an air filled balloon.
It seems disturbing that this would even be a question for anyone beyond primary school.
Guy de Maupassant wrote (as a sexual line) “nature abhors a vacuum and every vessel demands to be filled”
One of the greatest lines in literature.
What’s the difference between an absolute vacuum (that instantaneously sucks everything in) and absolute gravity (that also instantaneously sucks everything in)?!?!
You guys are still thinking in the box about vacuums.
Let alone offsets (Particle balances) (which we haven’t delved into yet).
Your primary school was worse a teacher to you than me dropping out of it.
Demanding something and getting it are two different things.
The difference is at least two fold. A vacuum is what is left after everything (at least the mass particles) have been attracted out of it or freed to leave the region. And also a vacuum doesn’t “suck” anything. A vacuum is the lack of anything that could do any sucking or anything else. Energized atoms (mass) race about and like migrants pouring into America, filling any unprotected (walled ) void but also race out of it. The vacuum is merely what hasn’t been yet filled by loose mass particles buzzing about (or any worthy thoughts filling a void of ignorance).
Just keep protecting that empty bubble. Maybe one day it will expand enough to float.
You put a bomb on the side of a plane. What happens? No cabin pressure anymore. The velocity of the plane (greater mass) sucks everything out of the hole you just made (lesser mass).
You’re really going to stand here with a straight face and tell me that no mass has a different property than infinite mass in terms of attraction?
Wipe your ass with your degree because it means nothing.
The air rushing by is what disallows an even number of atoms of air to enter the plane as the number that are carried away. More air leaves (on its own) than what enters. If the plane was not moving, has its mass changed? You really didn’t go to school (honest question)? And if you don’t mind, what country were you raised in?
I am still trying to figure out whether mass has any attraction at all (James has proposed a reason to believe that it doesn’t). But I am very confident that a vacuum, nothing at all, has no abilities to do anything. A vacuum is nothing but space. It just sits there. It isn’t really even an “it”. It is a region where there is no mass particles. It is up to mass-like things to enter that region or not due to whatever is propelling them at the time - their energy. If nothing around an empty space has any energy or motion of its own, the space would remain empty.
This is merely what the words mean. The word “vacuum” means that there is nothing there - nothing to do any sucking, blowing, or anything else. Otherwise it would not be called a “vacuum”.
The faster you pull the air out of a balloon, it will implode to destroy the structural integrity of the balloon. It will still pop, just as if you over extended it.
Here’s the deal with absolute vacuums:
They will scrunch every particle in existence at infinite speed so that they all collide with each other … this will create an explosion/expansion as they all hit each other at infinite speed and blow up! Like fireworks blow up or an atom bomb blow up.
You know… the thing I hate about physicists is that they think light is a cosmological constant. This is just bible and ancient Egyptian and mesapotamian cosmology (the sun god/the sun is the center of all things). I hate these backwards religious fucks.
Truth is: if a Big Bang really did occur, and light is a constant — our entire night sky would be white.
That means that something travels faster than light on some of our celestial objects (but not all of them)
So how does this relate to an absence of bosons?
Or radio waves, or light?
An absence of everything has the same gravitational pull as everything.
The concept is demonstrated over and over again when less air pressure pulls shit towards it that has greater air pressure. The ‘vacuum’ in this example.
The concept is also demonstrated when something with greater mass pulls something towards it.
What this means, and this is rudimentary science, is that masslessness acts the same as mass.
Well, if you leave me with a vacuous bubble, I’ll eventually absorb more knowledge and wisdom than the world combined. The bubble will erode at some point, if not collapse instantly, and all the knowledge of existence will flood into my brain.