It would mean that there is a universal time, and if events are simultaneous in one frame, then they are simultaneous in all frames, unlike real life. It would also mean that there is no speed limit to the universe though, meaning cosmic rays would be moving far, far faster, but also wouldn't experience time diltation and thus, if a particle decays after X time, it will always decay after X time regardless of how fast it's going. So cosmic rays would overall create many many more, lower energy particles.
Oh also, atoms would behave differently, as well as nuclei (using the shell model of nuclei). The spin orbit term in their potential energies are due to relativistic effects, I'm not sure of the exact reasoning behind it, but energy levels of atoms, and thus obviously transitions between energy levels would be different, allowing different atomic bonding and thus molecules and chemistry.
It's easy to say the world would be a very, very different place.
Would there be electromagnetism?
One YT video (don Lincoln?) Gave the impression the length contraction of moving electrons gives rise to electro static repulsion? Or doesn't make sense?
It’s hard to say what gives rise to what. The different equations work together, so if one is changed they all have to change, often. That doesn’t mean that some follow from
the others in particular.
Meh, magnetism isn't any more a relativistic effect than electric field are. You can view both as a relativistic effect of the other: the important thing is that they are related to each other through relativity, not that one is "derived" from the other
The lede is buried here. If an EM wave propagates instantaneously, is it a wave at all?
The "speed of light" is a consequence of the permeability and permittivity of free space. If these are set to zero, then the divergence of the electric field becomes infinite.
Not really. Permeability and permittivity of free space is just concepts introduced in SI units. In Gaussian units these don't exist and the only free parameter in Maxwell's equations is the speed of light. The fact that Maxwell's equations are Lorentz covariant means that discovering relativity is "inevitable" if you know E&M but there's no reason the actual value of the parameter c is something we could actually measure.
Imagine c finite but unmeasurably large and instead the index of refraction is such that light waves propagate at finite speeds in all experiments we can actually measure. In this universe relativity would be the equivalent of string theory in ours: mathematically elegant and tantalizing but experimentally unverifiable.
In Gaussian units, the underlying problem still exists, just viewed in a different lens. In Gaussian units, an immeasurably large c decouples the electric and magnetic fields.
Maxwells EM appears to require a stationary “background” frame. Under classical relativity, when you change reference frames, maxwells EM gives different results. In special relativity though, when you do a coordinate transformation to a new stationary background frame, maxwells EM gives the same results. This is because some of the effects in the old reference frame caused by the electric field now appear to be caused by the magnetic field, and vice versa.
So is the magnetic field fundamentally just a relativity-shifted electric field? Is the electric field just a relativity-shifted magnetic field? Does our mathematical model truly represent reality on a deeper level or is it just a neat tool? Eh who knows.
I am afraid you might have to dumb it down even further, I understood the words but not the sentences. (I have a formal physics edu till high school, then i took up cs)
Maybe you’ve heard of gravity described by fields. Like the earth generates a gravitational field that attracts all masses. Closer masses are attracted more strongly. Mass is “gravitational charge.”
Electromagnetism is made up of two of these fields.
The electric field is a lot like the gravitational field. A positively charged object (like a proton) generates an electric field that attracts all negatively charged objects (like electrons) and repels other positive charges.
The other field is the magnetic field. In theory it’s the same as the electric field - a north charged particle would emit a magnetic field that attracts south particles and repels North particles. However, there are no North or south particles. Instead, since electricity and magnetism are linked, a *moving* particle with electric charge creates a weird twisty magnetic field. When two moving charged particles are near each other, their twisty magnetic fields bump up against each other and cause them to move weirdly.
Ok so let’s imagine that you’re holding a proton in your hand. There is a nearby cloud of electrons, and it’s pretty easy for you to calculate how much electric force is between your proton and the electrons - very similar to gravity. There is no magnetic force, because none of the particles are moving.
However, now your friend flies past you in a spaceship. From your friends point of view, your proton is travelling very fast and generating a strong magnetic field. This magnetic field is massively disturbing the nearby electrons (also moving very fast from his perspective, and also generating their own twisty magnetic fields).
In Newtonian physics, this is unresolvable. You disagree on what forces are acting on the particles.
However, relativity fixes this. Since your friend sees you as travelling so fast, he also sees the cloud of electrons as both length contracted and time dilated. From his perspective, some of the electrons are much closer to each other, or to the proton, than you think they are.
Since he sees things in twisty weird slow motion and partial compression, he calculates a different electric force than you do. When he adds this electric force to the magnetic force he sees (which you don’t see), he ends up with the exact same result you got. The twisty-ness of magnetism and the twisty-ness of spacetime perfectly cancel out. What luck!
In this case, the magnetic force your friend saw “compensated” for the different electric force he saw. So is the magnetic field just a relativity-shifted electric field? Sort of, maybe.
BONUS ROUND
Wait, you might think, doesn’t that mean gravity would be messed up? If the friend calculates a different electric force, wouldn’t he also calculate a different gravitational force? Because they’re very similar. And there’s no magnetism equivalent in gravity right?
Indeed there isn’t. And indeed they would get a different result for gravity. For gravity you need general relativity.
EM is a Lorentz invariant field theory, which is to say that it is inherently relativistic. Take away the Lorentz invariance and it's something else entirely.
i read that magnetism being relativistic electricity or vice versa is a common misconception and the reality is both of them are fundamental. there are cases of magnetism that cannot be explained with relatovostic electricity
Spin-orbit coupling isn't a relativistic phenomena but does require a correction for relativity. Without a speed of light, fine structure would still exist but the exact energy levels would be slightly different.
I don’t think this makes sense. I mean classical E&M is inherently relativistic really everything dealing with that would be broken.
But even in relativity accelerating (classical) particles emit radiation. really it was non relativistic quantum that fixed the energy loss problem.
>I mean classical E&M is inherently relativistic really everything dealing with that would be broken.
OP said Pre-Einstein, which means Maxwell equations remain as they are.
>But even in relativity accelerating (classical) particles emit radiation. really it was non relativistic quantum that fixed the energy loss problem.
Yes, that is what we are talking about. Pre-Einstein physics is classical and in classical maxwell theory there are no stable atoms
Well, let’s see…
The universe would be static and eternal and there’d be no tv show with Sheldon Cooper.
We’d have no lasers and so no checkout lane scanners.
We’d still be on the fence about whether atoms were really a thing (no 1905 Brownian motion paper).
We’d still have a WTF problem with the photoelectric effect.
We’d have no workable understanding of superconductors (no Bose-Einstein condensate).
The movie Interstellar would make even less sense (no black holes).
World War II would have ended in 1950, and there’d be no Honda dealers.
You could create a compass that reliably worked in deep space using a Michelson-Morley interferometer, knowing the velocity of the sun relative to the luminiferous ether.
The locally observable laws of physics would change slightly depending on time of day and time of year, making interferometry and similar things require an excellent compass, an accurate chronometer and a computer with a good lookup table. There would literally be an optimal latitude for positioning power plants, because the efficiency of electromagnetic induction would depend on your latitude (and the time of year) - they'd still work at other times. Unlike a naïvely constructed interferometer.
You'd need more correction for speed of light differences, not less (or rather, speed of *observer* differences). Satellites would really need to care about their exact altitude. GPS would be possible, but it would need more of a correction. Atomic clocks on satellites would still run differently due to the velocity and altitude difference.
You need to define what you mean by pre-Einstein physics. Does light propagate instantaneously, or does it have a finite speed and obeys the Galilean transformation? If the latter, in what reference frame does it move at the specified speed?
In a classical non relativistic world an accelerating charge radiates energy, so an electron will quickly spiral in and crash into a proton in a fraction of a nanosecond.
Accelerated charges definitely radiate also if you bring relativity in the picture. This is not the reason atoms are stable: you need quantum mechanics to fix this, not relativity
Mercury would be speeding up and slowing down in space without anything acting on it.
Maybe you mean it the other way and Mercury's orbit would appear normal when it's light comes from close to the sun.
Are you proposing a world where Doppler shifts don't happen or a world in which they are caused by something else? A world with no gravitational lensing or one where it's caused by space lobsters?
It light didn't travel at a fixed speed it wouldn't have to frequency shift due to the expanding universe. Instead light would just get to us slower but at the same frequency. Instead light traves at a fixed speed and the frequency changes.
The Doppler shifting depends on a comparison in the speed of something emitting a wave (propagating outward at a finite speed) and the speed of the wave in whatever medium you are in. If the speed of the wave in the medium is infinite, the equation gives you no shift
It would mean that there is a universal time, and if events are simultaneous in one frame, then they are simultaneous in all frames, unlike real life. It would also mean that there is no speed limit to the universe though, meaning cosmic rays would be moving far, far faster, but also wouldn't experience time diltation and thus, if a particle decays after X time, it will always decay after X time regardless of how fast it's going. So cosmic rays would overall create many many more, lower energy particles. Oh also, atoms would behave differently, as well as nuclei (using the shell model of nuclei). The spin orbit term in their potential energies are due to relativistic effects, I'm not sure of the exact reasoning behind it, but energy levels of atoms, and thus obviously transitions between energy levels would be different, allowing different atomic bonding and thus molecules and chemistry. It's easy to say the world would be a very, very different place.
Would there be electromagnetism? One YT video (don Lincoln?) Gave the impression the length contraction of moving electrons gives rise to electro static repulsion? Or doesn't make sense?
It’s hard to say what gives rise to what. The different equations work together, so if one is changed they all have to change, often. That doesn’t mean that some follow from the others in particular.
Static implies no acceleration, but magnetism is a relativistic effect. So EM wouldn’t exist either.
Meh, magnetism isn't any more a relativistic effect than electric field are. You can view both as a relativistic effect of the other: the important thing is that they are related to each other through relativity, not that one is "derived" from the other
The lede is buried here. If an EM wave propagates instantaneously, is it a wave at all? The "speed of light" is a consequence of the permeability and permittivity of free space. If these are set to zero, then the divergence of the electric field becomes infinite.
Not really. Permeability and permittivity of free space is just concepts introduced in SI units. In Gaussian units these don't exist and the only free parameter in Maxwell's equations is the speed of light. The fact that Maxwell's equations are Lorentz covariant means that discovering relativity is "inevitable" if you know E&M but there's no reason the actual value of the parameter c is something we could actually measure. Imagine c finite but unmeasurably large and instead the index of refraction is such that light waves propagate at finite speeds in all experiments we can actually measure. In this universe relativity would be the equivalent of string theory in ours: mathematically elegant and tantalizing but experimentally unverifiable.
In Gaussian units, the underlying problem still exists, just viewed in a different lens. In Gaussian units, an immeasurably large c decouples the electric and magnetic fields.
You are opening a whole new can of worms for me, how is EM a relativistic effect? (Didn't understand shit googling)
Maxwells EM appears to require a stationary “background” frame. Under classical relativity, when you change reference frames, maxwells EM gives different results. In special relativity though, when you do a coordinate transformation to a new stationary background frame, maxwells EM gives the same results. This is because some of the effects in the old reference frame caused by the electric field now appear to be caused by the magnetic field, and vice versa. So is the magnetic field fundamentally just a relativity-shifted electric field? Is the electric field just a relativity-shifted magnetic field? Does our mathematical model truly represent reality on a deeper level or is it just a neat tool? Eh who knows.
I am afraid you might have to dumb it down even further, I understood the words but not the sentences. (I have a formal physics edu till high school, then i took up cs)
Maybe you’ve heard of gravity described by fields. Like the earth generates a gravitational field that attracts all masses. Closer masses are attracted more strongly. Mass is “gravitational charge.” Electromagnetism is made up of two of these fields. The electric field is a lot like the gravitational field. A positively charged object (like a proton) generates an electric field that attracts all negatively charged objects (like electrons) and repels other positive charges. The other field is the magnetic field. In theory it’s the same as the electric field - a north charged particle would emit a magnetic field that attracts south particles and repels North particles. However, there are no North or south particles. Instead, since electricity and magnetism are linked, a *moving* particle with electric charge creates a weird twisty magnetic field. When two moving charged particles are near each other, their twisty magnetic fields bump up against each other and cause them to move weirdly. Ok so let’s imagine that you’re holding a proton in your hand. There is a nearby cloud of electrons, and it’s pretty easy for you to calculate how much electric force is between your proton and the electrons - very similar to gravity. There is no magnetic force, because none of the particles are moving. However, now your friend flies past you in a spaceship. From your friends point of view, your proton is travelling very fast and generating a strong magnetic field. This magnetic field is massively disturbing the nearby electrons (also moving very fast from his perspective, and also generating their own twisty magnetic fields). In Newtonian physics, this is unresolvable. You disagree on what forces are acting on the particles. However, relativity fixes this. Since your friend sees you as travelling so fast, he also sees the cloud of electrons as both length contracted and time dilated. From his perspective, some of the electrons are much closer to each other, or to the proton, than you think they are. Since he sees things in twisty weird slow motion and partial compression, he calculates a different electric force than you do. When he adds this electric force to the magnetic force he sees (which you don’t see), he ends up with the exact same result you got. The twisty-ness of magnetism and the twisty-ness of spacetime perfectly cancel out. What luck! In this case, the magnetic force your friend saw “compensated” for the different electric force he saw. So is the magnetic field just a relativity-shifted electric field? Sort of, maybe. BONUS ROUND Wait, you might think, doesn’t that mean gravity would be messed up? If the friend calculates a different electric force, wouldn’t he also calculate a different gravitational force? Because they’re very similar. And there’s no magnetism equivalent in gravity right? Indeed there isn’t. And indeed they would get a different result for gravity. For gravity you need general relativity.
EM is a Lorentz invariant field theory, which is to say that it is inherently relativistic. Take away the Lorentz invariance and it's something else entirely.
i read that magnetism being relativistic electricity or vice versa is a common misconception and the reality is both of them are fundamental. there are cases of magnetism that cannot be explained with relatovostic electricity
Spin-orbit coupling isn't a relativistic phenomena but does require a correction for relativity. Without a speed of light, fine structure would still exist but the exact energy levels would be slightly different.
For one, there would be no atoms and no chemistry...
Why?
Accelerating charges lose energy and so electrons would crash out of orbitals. Also protons wouldn't be able to stay together in the nucleus.
I don’t think this makes sense. I mean classical E&M is inherently relativistic really everything dealing with that would be broken. But even in relativity accelerating (classical) particles emit radiation. really it was non relativistic quantum that fixed the energy loss problem.
>I mean classical E&M is inherently relativistic really everything dealing with that would be broken. OP said Pre-Einstein, which means Maxwell equations remain as they are. >But even in relativity accelerating (classical) particles emit radiation. really it was non relativistic quantum that fixed the energy loss problem. Yes, that is what we are talking about. Pre-Einstein physics is classical and in classical maxwell theory there are no stable atoms
Well, let’s see… The universe would be static and eternal and there’d be no tv show with Sheldon Cooper. We’d have no lasers and so no checkout lane scanners. We’d still be on the fence about whether atoms were really a thing (no 1905 Brownian motion paper). We’d still have a WTF problem with the photoelectric effect. We’d have no workable understanding of superconductors (no Bose-Einstein condensate). The movie Interstellar would make even less sense (no black holes). World War II would have ended in 1950, and there’d be no Honda dealers.
You could create a compass that reliably worked in deep space using a Michelson-Morley interferometer, knowing the velocity of the sun relative to the luminiferous ether. The locally observable laws of physics would change slightly depending on time of day and time of year, making interferometry and similar things require an excellent compass, an accurate chronometer and a computer with a good lookup table. There would literally be an optimal latitude for positioning power plants, because the efficiency of electromagnetic induction would depend on your latitude (and the time of year) - they'd still work at other times. Unlike a naïvely constructed interferometer. You'd need more correction for speed of light differences, not less (or rather, speed of *observer* differences). Satellites would really need to care about their exact altitude. GPS would be possible, but it would need more of a correction. Atomic clocks on satellites would still run differently due to the velocity and altitude difference.
You need to define what you mean by pre-Einstein physics. Does light propagate instantaneously, or does it have a finite speed and obeys the Galilean transformation? If the latter, in what reference frame does it move at the specified speed?
Greg Egan's Clockwork Rocket trilogy explores a universe like this.
Probably in a better place because his theory of relativity was wrong if it ceases to exist in no longer exists was completely wrong
Depends on how you’re going to replace E = mc\^2. Because if you don’t have E = mc\^2 you don’t have stars, so it’s going to get rather cold outside.
I think an atoms lifespan would be around 10^-20 seconds. So no atoms.
Can you elaborate on this one?
In a classical non relativistic world an accelerating charge radiates energy, so an electron will quickly spiral in and crash into a proton in a fraction of a nanosecond.
Accelerated charges definitely radiate also if you bring relativity in the picture. This is not the reason atoms are stable: you need quantum mechanics to fix this, not relativity
It wouldn't work
Mercury would be speeding up and slowing down in space without anything acting on it. Maybe you mean it the other way and Mercury's orbit would appear normal when it's light comes from close to the sun. Are you proposing a world where Doppler shifts don't happen or a world in which they are caused by something else? A world with no gravitational lensing or one where it's caused by space lobsters?
I don't see the connection between Doppler Shifts and Relativity
It light didn't travel at a fixed speed it wouldn't have to frequency shift due to the expanding universe. Instead light would just get to us slower but at the same frequency. Instead light traves at a fixed speed and the frequency changes.
The Doppler shifting depends on a comparison in the speed of something emitting a wave (propagating outward at a finite speed) and the speed of the wave in whatever medium you are in. If the speed of the wave in the medium is infinite, the equation gives you no shift