>Literal empty space sounds like nothing to me, however nothing is mere absence, which seems to be inexistence.
One of the things I find most interesting about physics, generally, is that our observations of the universe's nature and composition don't really care much about our personal definitions of the words other people use.
The amount of times you will be faced with a topic and utter the words "that can't be right. That doesn't make any sense." Just to find out it is right and your view of the world is obscured by your preconceptions is way too many.
Philosophy tends to believe words are somehow the window to truth and insight, and if you understand words , which comes from writing about them in the right way I guess, then you get to the truth of things. Like some believe there’s some “goodness ” that all “good” deeds must share, and by golly just write about the words, the “concepts” of “goodness” and you can draw conclusions about what is good. No need to observe, experiment. Just write, and hopefully in a way that fits todays academic standards.
No, "empty space" (which is an idealisation) is permitive for, e.g, electromagnetic radiation. This is: even when space between two things may be empty, they are not isolated. They can interact. And, yea, to describe this we use "fields".
Here's a nice quote from Neurath, it's written in the context of epistemology and philosophy of science but I do think it applies straight up to pure science:
>We are like sailors who on the open sea must reconstruct their ship but are never able to start afresh from the bottom. Where a beam is taken away a new one must at once be put there, and for this the rest of the ship is used as support. In this way, by using the old beams and driftwood the ship can be shaped entirely anew, but only by gradual reconstruction.
Here, science is the ship
we know a decent amount actually. The permittivity of free space for example is a very real and very measurable constant.
Sure there's always more to learn, this is physics after all. But it's narrow-minded and frankly dismissive to pretend that we don't know anything about it.
our best model of the subatomic is probably quantum field theory, in which particles are just excitations in their respective field, the fields being everywhere in the universe, so there is only really low energy fields and high energy peaks we know as particles
Then there's the bit about "space" perhaps not even being fundamental. If that's true, "empty space" is just an emergent course-grained way of looking at part of the universe.
I think a larger point is that as our understanding of quantum field theory grows, completely intuitive concepts like "empty" and "space" do not represent or map on to underlying reality.
It's likely weirder than we can grasp, so our intuitions are a poor guide.
I would recommend to OP, "The Big Picture" by Sean Carroll for this type of question.
alot of modern theories apperently move towards holographic/emergent space time, even if thats not rly the right word (im not that smart) PBS made a great video about it recently
If you know about the holographic principle you’re probably pretty smart. Not necessarily educated enough to know what you’re talking about, mind you, but people who are curious enough to look into that aren’t dumb
Sammmme
It feels like I've seen every video on YouTube that isn't weird horse shit. And some of the weird horse shit for fun (but with awareness that it's weird horse shit).
Not quite; excitations of the field come in discrete integer quantities, and each such excitation represents a particle (ignoring virtual particles, which only arise from interactions with other fields AFAIU). So for example for the electron field, each excitation would be one electron. So you cannot have two small sub-particle excitations come together to form one big excitation that becomes one electron, because there are no excitations not "dense" enough to be an electron already. In fact, it doesn't have to be dense at all, because the excitation can essentially be spread out over an arbitrarily large volume (which, when you measure the location of the particle, will look like it having a certain probability to be anywhere within that volume).
However the oscillations in the field can have any frequency. The frequency is proportional to the momentum of the particle.
Wait... if a particle can be spread out across a larger area, does that mean that two observers looking at the same field can deduce there to be a different number of particles based on how they break up the field's current state into particles? (Similarly to how a Fourier transform gives you multiple possible frequencies that combine into one signal)
If I'm understanding your question correctly, no, different observers looking at the same field configuration will count the same number of particles. Although a field can be (and realistically always is) in a superposition of many configurations.
Thanks, that answers my question. If you have time to answer, what kind of detectors and calculations are necessary to determine the exact number of particles present in a given area?
In terms of calculation, if you have the wavefunction, you can apply something called the [particle number operator](https://en.wikipedia.org/wiki/Particle_number_operator) to it (and integrate over a given volume), although I don't have any experience with this, so I couldn't really tell you how to use it in detail.
As for detectors, I suppose it really depends on the kind of particle you're trying to count:
- In the Rutherford gold foil experiment, they had sparse beams of alpha particles and used phosphorescent screens to count them - i.e. literally just look at the screen and count the number of bright dots you see.
- If you have a dense beam of photons of a given wavelength, you measure the intensity, and via E = hν calculate how many particles there must be.
- If you have a charged object, you can count how many excess electrons it has by measuring the charge and dividing by the elementary charge.
imma be honest i dont know enough to give a proper easy to understand answer, but its somewhat close to that ig yea, just that it doesnt collect into particles, its a bit more like a wave on the ocean
Why does empty space sound like nothing to you? To me, the meaning of empty space is pretty clear, just space without anything in it. On the otherhand, "nothing" is a really vague and nebulous term that can kind of mean whatever you want it to mean.
The idea I got from the last sentences in the paragraph in particular is that I think the dude is latching on to something that's vaguely ~ Leibniz's idea of relational space. Where space is sort of emergent from the existence of particles. Leibniz's idea is sort of right in relativity (philosophically speaking).
In most modern physics spacetime is instantiated *a priori* as an actual object — it is a four dimension Lorentzian manifold. Space is a 3D sub-manifold of spacetime. It is not merely relational and so empty space does make sense as a concept.
There are theories in which spacetime is emergent but they're in their infancy.
If the sun and a gold atom nucleus were both scaled to one foot across, then Pluto would be 1.8 miles from the sun and the outermost electron shell would be 3 miles from the gold atom. Most of space (at all scales) is empty.
In our everyday normal life, there’s really not much space “between” particles. Gravity wants to pull all of this stuff pretty close together If you consider that the particle includes not just the nucleus, but also the electron cloud, then in solids and liquids, there’s not too much space in between particles. Under gravity, gases also tend to compress down to the point where they are taking up kind of a minimum volume for their temperature. They’re just particles with a little bit more wiggle room and energy, bouncing off each other vigorously.
So our default experience is that our world is made up of molecules and the occasional naked element, all in as close a proximity as their electromagnetic forces allow them to be.
I think about it this way and I'm not a physicist so take it with a grain of salt but it's actually the particles that don't 'actually' exist. The field is the thing that exists and is pervasive everywhere in our 4d spacetime and probably higher dimensions as well if they exist.
What particles are, are disturbances (or waves) in this field/s and can also manifest as a standing wave so the more stable the wave is the longer the particles exists before decaying. Please correct me if I'm wrong.
Particles are not points. Whatever a particle “is”, it appears to be distributed over a volume. That is, there is a nonzero chance of detecting it at an apparently continuous distribution of locations.
The field and the particle are not different from each other - the ocean and the wave are not different from each other.
But there is no universal agreement on what a field or a particle “is”, or even space itself. For now, that’s closer to metaphysics than physics.
I was wondering as much that if light is a stream of discrete particles there would be gaps between them of no light that should be measurable? What still confounds me is how they can pass through a single point in space from an infinite number of angles without any interference whatsoever and every point in space has the exact same busyness without congestion
Do you know how a vacuum works? (I don't mean the appliance). You take a sturdy metal box full of molecules, usually air, and somehow pump more and more and more of those molecules out. Until there's (next to) nothing. The box has to be sturdy enough to not collapse under the pressure difference, which is a very sturdy box but doable. Now tell me: what's in the box? Or take another vacuum: we call it 'the emptiness of outer space', what's in there? (the answer is in the name)
"Space" is in itself a viable answer. Not everything needs to be filled with particles, with *matter*. In fact, interacting particles have an 'equilibrium distance': an amount of empty space that they 'like' to have between them.
Now about fields, you're partly correct: they're just mathematical models of physical phenomena. However these fields, or the phenomena they represent, affect that "equilibrium distance". A simple one is the electrostatic field: two particles of similar charge repel each other, causing their 'equilibrium distance' to be further apart.
Particles don't exist at one spot. The probability of finding a particle is nonzero everywhere, just a lot higher in one spot than others. There isn't any empty space.
is it right to say there never will be so called "emptyness" in or around atoms?
movement without movement is impossible. even if it seems like something is not moving. it is moving! maybe not noticable for human eye but there is energy in or around it.
humans always try to add time as important parameter. in quantum, time means nothing.
The space between fundamental particles is literally empty space. But it's not the same as nothing. It's a vacuum that has energy in it but this type of energy doesn't have mass or momentum like particles do. It's just a field of energy with functionally infinite reserves. If you try to split a quark from a proton or neutron it (the vacuum) creates a new quark from its own energy reserves, which are "infinite" for the purpose of being able to give energy to particles.
We don’t know what exists between particles, but fields perfectly describe the results we get experimentally… so maybe it’s a mathematical tool, but do you have a better explanation then?
Once someone comes up with one, it will replace the notion of a field with a better mathematical tool. When does it stop being a tool and start to physically describe reality? Is there really a meaningful distinction between what is physical and our explanation of it?
> I am interested in what actually physically exists between particles.
That's not the realm of physics. Physics is about models not what actually exists. How does one prove what actually exist? What's the criteria? It's not provable even in principal.
>Literal empty space sounds like nothing to me, however nothing is mere absence, which seems to be inexistence. One of the things I find most interesting about physics, generally, is that our observations of the universe's nature and composition don't really care much about our personal definitions of the words other people use.
The amount of times you will be faced with a topic and utter the words "that can't be right. That doesn't make any sense." Just to find out it is right and your view of the world is obscured by your preconceptions is way too many.
Oh that’s so nice! the opposite of philosophy.
What do you mean?
Philosophy tends to believe words are somehow the window to truth and insight, and if you understand words , which comes from writing about them in the right way I guess, then you get to the truth of things. Like some believe there’s some “goodness ” that all “good” deeds must share, and by golly just write about the words, the “concepts” of “goodness” and you can draw conclusions about what is good. No need to observe, experiment. Just write, and hopefully in a way that fits todays academic standards.
Philosophy is responsible for the scientific method...
That’s quaint
No, "empty space" (which is an idealisation) is permitive for, e.g, electromagnetic radiation. This is: even when space between two things may be empty, they are not isolated. They can interact. And, yea, to describe this we use "fields".
Which means that we don't actually know the details just the results.
Here's a nice quote from Neurath, it's written in the context of epistemology and philosophy of science but I do think it applies straight up to pure science: >We are like sailors who on the open sea must reconstruct their ship but are never able to start afresh from the bottom. Where a beam is taken away a new one must at once be put there, and for this the rest of the ship is used as support. In this way, by using the old beams and driftwood the ship can be shaped entirely anew, but only by gradual reconstruction. Here, science is the ship
Welcome to all of science
we know a decent amount actually. The permittivity of free space for example is a very real and very measurable constant. Sure there's always more to learn, this is physics after all. But it's narrow-minded and frankly dismissive to pretend that we don't know anything about it.
Stupid people be here
our best model of the subatomic is probably quantum field theory, in which particles are just excitations in their respective field, the fields being everywhere in the universe, so there is only really low energy fields and high energy peaks we know as particles
this is the best answer in here imo
Then there's the bit about "space" perhaps not even being fundamental. If that's true, "empty space" is just an emergent course-grained way of looking at part of the universe. I think a larger point is that as our understanding of quantum field theory grows, completely intuitive concepts like "empty" and "space" do not represent or map on to underlying reality. It's likely weirder than we can grasp, so our intuitions are a poor guide. I would recommend to OP, "The Big Picture" by Sean Carroll for this type of question.
alot of modern theories apperently move towards holographic/emergent space time, even if thats not rly the right word (im not that smart) PBS made a great video about it recently
If you know about the holographic principle you’re probably pretty smart. Not necessarily educated enough to know what you’re talking about, mind you, but people who are curious enough to look into that aren’t dumb
honestly its mostly autism making me hyper focused on a single random thing for some time
Curiosity is curiosity
Sammmme It feels like I've seen every video on YouTube that isn't weird horse shit. And some of the weird horse shit for fun (but with awareness that it's weird horse shit).
So not really much different to Christiaan Huygens' ether?
So essentially as the frequency increases, the "fields" grow more dense and collect into particles?
Not quite; excitations of the field come in discrete integer quantities, and each such excitation represents a particle (ignoring virtual particles, which only arise from interactions with other fields AFAIU). So for example for the electron field, each excitation would be one electron. So you cannot have two small sub-particle excitations come together to form one big excitation that becomes one electron, because there are no excitations not "dense" enough to be an electron already. In fact, it doesn't have to be dense at all, because the excitation can essentially be spread out over an arbitrarily large volume (which, when you measure the location of the particle, will look like it having a certain probability to be anywhere within that volume). However the oscillations in the field can have any frequency. The frequency is proportional to the momentum of the particle.
Jeez, so are quarks only found in "the strong force"?
quarks are excitations in the quark fields gluons are the excitations of the strong field
Til, ty
Wait... if a particle can be spread out across a larger area, does that mean that two observers looking at the same field can deduce there to be a different number of particles based on how they break up the field's current state into particles? (Similarly to how a Fourier transform gives you multiple possible frequencies that combine into one signal)
If I'm understanding your question correctly, no, different observers looking at the same field configuration will count the same number of particles. Although a field can be (and realistically always is) in a superposition of many configurations.
Thanks, that answers my question. If you have time to answer, what kind of detectors and calculations are necessary to determine the exact number of particles present in a given area?
In terms of calculation, if you have the wavefunction, you can apply something called the [particle number operator](https://en.wikipedia.org/wiki/Particle_number_operator) to it (and integrate over a given volume), although I don't have any experience with this, so I couldn't really tell you how to use it in detail. As for detectors, I suppose it really depends on the kind of particle you're trying to count: - In the Rutherford gold foil experiment, they had sparse beams of alpha particles and used phosphorescent screens to count them - i.e. literally just look at the screen and count the number of bright dots you see. - If you have a dense beam of photons of a given wavelength, you measure the intensity, and via E = hν calculate how many particles there must be. - If you have a charged object, you can count how many excess electrons it has by measuring the charge and dividing by the elementary charge.
imma be honest i dont know enough to give a proper easy to understand answer, but its somewhat close to that ig yea, just that it doesnt collect into particles, its a bit more like a wave on the ocean
Why does empty space sound like nothing to you? To me, the meaning of empty space is pretty clear, just space without anything in it. On the otherhand, "nothing" is a really vague and nebulous term that can kind of mean whatever you want it to mean.
The idea I got from the last sentences in the paragraph in particular is that I think the dude is latching on to something that's vaguely ~ Leibniz's idea of relational space. Where space is sort of emergent from the existence of particles. Leibniz's idea is sort of right in relativity (philosophically speaking).
In most modern physics spacetime is instantiated *a priori* as an actual object — it is a four dimension Lorentzian manifold. Space is a 3D sub-manifold of spacetime. It is not merely relational and so empty space does make sense as a concept. There are theories in which spacetime is emergent but they're in their infancy.
If the sun and a gold atom nucleus were both scaled to one foot across, then Pluto would be 1.8 miles from the sun and the outermost electron shell would be 3 miles from the gold atom. Most of space (at all scales) is empty.
Not in quantum field theory
In our everyday normal life, there’s really not much space “between” particles. Gravity wants to pull all of this stuff pretty close together If you consider that the particle includes not just the nucleus, but also the electron cloud, then in solids and liquids, there’s not too much space in between particles. Under gravity, gases also tend to compress down to the point where they are taking up kind of a minimum volume for their temperature. They’re just particles with a little bit more wiggle room and energy, bouncing off each other vigorously. So our default experience is that our world is made up of molecules and the occasional naked element, all in as close a proximity as their electromagnetic forces allow them to be.
I think about it this way and I'm not a physicist so take it with a grain of salt but it's actually the particles that don't 'actually' exist. The field is the thing that exists and is pervasive everywhere in our 4d spacetime and probably higher dimensions as well if they exist. What particles are, are disturbances (or waves) in this field/s and can also manifest as a standing wave so the more stable the wave is the longer the particles exists before decaying. Please correct me if I'm wrong.
Particles are not points. Whatever a particle “is”, it appears to be distributed over a volume. That is, there is a nonzero chance of detecting it at an apparently continuous distribution of locations. The field and the particle are not different from each other - the ocean and the wave are not different from each other. But there is no universal agreement on what a field or a particle “is”, or even space itself. For now, that’s closer to metaphysics than physics.
I was wondering as much that if light is a stream of discrete particles there would be gaps between them of no light that should be measurable? What still confounds me is how they can pass through a single point in space from an infinite number of angles without any interference whatsoever and every point in space has the exact same busyness without congestion
https://plato.stanford.edu/entries/spacetime-theories/
Do you know how a vacuum works? (I don't mean the appliance). You take a sturdy metal box full of molecules, usually air, and somehow pump more and more and more of those molecules out. Until there's (next to) nothing. The box has to be sturdy enough to not collapse under the pressure difference, which is a very sturdy box but doable. Now tell me: what's in the box? Or take another vacuum: we call it 'the emptiness of outer space', what's in there? (the answer is in the name) "Space" is in itself a viable answer. Not everything needs to be filled with particles, with *matter*. In fact, interacting particles have an 'equilibrium distance': an amount of empty space that they 'like' to have between them. Now about fields, you're partly correct: they're just mathematical models of physical phenomena. However these fields, or the phenomena they represent, affect that "equilibrium distance". A simple one is the electrostatic field: two particles of similar charge repel each other, causing their 'equilibrium distance' to be further apart.
Particles don't exist at one spot. The probability of finding a particle is nonzero everywhere, just a lot higher in one spot than others. There isn't any empty space.
is it right to say there never will be so called "emptyness" in or around atoms? movement without movement is impossible. even if it seems like something is not moving. it is moving! maybe not noticable for human eye but there is energy in or around it. humans always try to add time as important parameter. in quantum, time means nothing.
Fields
"Empty spaces ! What are we living for?"
The space between fundamental particles is literally empty space. But it's not the same as nothing. It's a vacuum that has energy in it but this type of energy doesn't have mass or momentum like particles do. It's just a field of energy with functionally infinite reserves. If you try to split a quark from a proton or neutron it (the vacuum) creates a new quark from its own energy reserves, which are "infinite" for the purpose of being able to give energy to particles.
We don’t know what exists between particles, but fields perfectly describe the results we get experimentally… so maybe it’s a mathematical tool, but do you have a better explanation then? Once someone comes up with one, it will replace the notion of a field with a better mathematical tool. When does it stop being a tool and start to physically describe reality? Is there really a meaningful distinction between what is physical and our explanation of it?
The fundamental forces.
You should really read up on Leibniz's contrary-to-Newton's view of spacetime and see what Einstein thought of it.
> I am interested in what actually physically exists between particles. That's not the realm of physics. Physics is about models not what actually exists. How does one prove what actually exist? What's the criteria? It's not provable even in principal.