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Magenta does not exist
I'm sorry if this shocks you. I'll leave you some time to recover. Of course magenta is a colour, you can see it. My little gay banner up there is magenta. But magenta only exists in your mind. Visible light is made up of the band of colours which represent electromagnetic radiation of between about 390 and 750 nm. Here is a diagram that represents the full range of wavelengths our eyes can see:
From general experience with mixing colours and intuition you would think that when the brain sees two wavelenghts at once you see a colour that is of a wavelength between those two. If you see red and yellow at once you interoperate it as orange. If you see yellow and blue at once you interoperate it as green. So if you see red and violet at once you interoperate it as, well, also green by that logic. Green is about half way between those two colours on the spectrum pictured above. But our brains know that seeing a mix of violet and red as the same as blue and yellow would be dumb, so that's not actually how the brain does it. For mixing red and violent your brain invents a new colour that has no wavelength associate with it that we know as magenta.
(there are actually loads of shades that have do not have their own wavelength, not just magenta, but magenta is the most fabulous one).
Bonus fact: Our eyes are more sensitive to green that red or blue. If you turn on a red and green laser of exactly the same power the green one will appear brighter. We can also see more shades of green than the other two, which is why they use it for night-vision displays.
Magnetism does not exist
Magnetism is weird. Much weirder than people realise. I'm going to have to go into a bit of detail here. Magnetic fields only exist when electric charges are moving. In any bar magnet you have little swirls of electrons spinning around inside it creating the magnetic field around it. In an electromagnet when you put electricity through the electrons zipping along the coils. Actually, ever wire with electricity running through it generates a magnetic field, it's just they're normally extremely weak.
Part 1: Introduction to electromagnetism
Electric charges themselves are pretty simple. There are negative charges (electrons mostly) and positive charges (protons). Like charges repel each other and opposite charges attract each other and moving charges cause magnetic fields around them. Now here's the first really weird part. Magnetic fields also act on moving electric charges and only on moving charges. So all electric charges make an electric field that effect all electric charges, and magnetic fields that are made my moving electric charges and only affect moving electric charges.
And how magnetic fields affects electric charges is also weird. So, imagine in the room you're sitting there's a giant north pole of a magnet to your left and a giant south pole to your right. That means there's a strong magnetic field going from left to right and I'm going to be assuming that this field is uniform (ie, it's the same strength at every point in the room). Now imagine you have a ball with a positive charge on it. If it's sitting still the magnetic field will do nothing to it. Now, if you throw it forward you know where the magnetic field will push the ball? Upwards into the ceiling! Magnetic fields are weird.
Part 2: The apparent problem
But there is no such thing as an absolute measure of velocity. When we measure how fast something is going we measure it compared to the Earth, which we treat as stationary. But when we give the speed of the Earth we give it as a figure of how fast it's going around the Sun and treat that as stationary. But the Sun isn't stationary either, it's moving through the Milky Way the entire time.
We can only ever say how fast something is going relative to something else. That something else we call a reference frame. Like I said the usual reference frame is the Earth. But reference frames are arbitrary. We can pick any reference frame and it makes no difference to the laws of physics (unless the reference frame is accelerating but let's not get into that).
So remember when I said magnetic fields only affect charges that are moving? So lets go back to the example of a ball of charge going forward with magnets to either side of the room. In the reference frame of the room the ball moves forward through the magnetic field and as I said it flies upwards. In the reference frame of the ball it's not even moving so therefore it shouldn't feel any force from the magnetic field and nothing should happen. And no, the charge won't feel the field moving against it if it's a uniform field.
By the classical laws of physics when you do the calculations from one reference frame on thing happens and when you do it in another reference frame something else happens. This is not supposed to happen. So now I'm finally getting to the point of this. What is happening? Well I assume you've all heard of Einstein's Special Theory of Relativity, but I doubt most of you know it was devised to explain
Part 3: ****ing magnets, how do they work?
So imagine now we have a ball of electric charge like in the earlier example but this time we have it next to a wire with a current going through it. For simplicity we shall imagine the wire as being like a tube with two things in it: Electrons moving all with the same speed along the wire (electrons are negatively charged) and stationary ions (positively charged). Here's a diagram:
The negative electrons and positive ions are evenly spaced and our ball of positive charge feels no overall electric force from them. There is also a magnetic field present but it doesn't affect our ball as it's currently stationary. So lets say the ball starts to move. For simplicity I will assume the ball moves to the right at the same speed as the electrons (hence there will be no relative motion between the ball and the electrons). We know in the reference frame where the wire is stationary the ball will feel a force from the magnetic field (in this case it will be pushed down and away from the wire). But what happens in the frame where the ball is stationary and the wire is moving? Here's a new diagram:
So we have a stationary positive charge, stationary electrons and ions moving to the left now. You may have noticed that there are now more ions in the picture than electrons. This is not a mistake. Special relativity is an interesting thing. You've probably heard of the twin paradox. It's about how in special relativity that time moves slower for faster moving objects. There is a less known effect called length contraction where if something is moving towards or away from you, it is shorter based on how fast it's moving.
The individual electrons going along the wire in the first diagram are length contracted too but it doesn't affect the distribution of charge, but when the wire starts moving relative to the ball its length gets contracted and as the wire is made of these positive ions the ions get smushed closer together. Now there are more positive charges near our ball than negative charges and since the ball is also positive it will be pushed away from the wire, downward, just like it was in the reference frame where the wire was stationary and the ball was moving.
This is what magnetism is. As far as the charge is concerned it never feels a magnetic field, just an electric one. Magnetic fields are electric fields in a different reference frame due to special relativity. So now you know how magnets work and scientists no longer have to be getting you pissed!
I'm sorry if this shocks you. I'll leave you some time to recover. Of course magenta is a colour, you can see it. My little gay banner up there is magenta. But magenta only exists in your mind. Visible light is made up of the band of colours which represent electromagnetic radiation of between about 390 and 750 nm. Here is a diagram that represents the full range of wavelengths our eyes can see:
From general experience with mixing colours and intuition you would think that when the brain sees two wavelenghts at once you see a colour that is of a wavelength between those two. If you see red and yellow at once you interoperate it as orange. If you see yellow and blue at once you interoperate it as green. So if you see red and violet at once you interoperate it as, well, also green by that logic. Green is about half way between those two colours on the spectrum pictured above. But our brains know that seeing a mix of violet and red as the same as blue and yellow would be dumb, so that's not actually how the brain does it. For mixing red and violent your brain invents a new colour that has no wavelength associate with it that we know as magenta.
(there are actually loads of shades that have do not have their own wavelength, not just magenta, but magenta is the most fabulous one).
Bonus fact: Our eyes are more sensitive to green that red or blue. If you turn on a red and green laser of exactly the same power the green one will appear brighter. We can also see more shades of green than the other two, which is why they use it for night-vision displays.
Magnetism does not exist
Magnetism is weird. Much weirder than people realise. I'm going to have to go into a bit of detail here. Magnetic fields only exist when electric charges are moving. In any bar magnet you have little swirls of electrons spinning around inside it creating the magnetic field around it. In an electromagnet when you put electricity through the electrons zipping along the coils. Actually, ever wire with electricity running through it generates a magnetic field, it's just they're normally extremely weak.
Part 1: Introduction to electromagnetism
Electric charges themselves are pretty simple. There are negative charges (electrons mostly) and positive charges (protons). Like charges repel each other and opposite charges attract each other and moving charges cause magnetic fields around them. Now here's the first really weird part. Magnetic fields also act on moving electric charges and only on moving charges. So all electric charges make an electric field that effect all electric charges, and magnetic fields that are made my moving electric charges and only affect moving electric charges.
And how magnetic fields affects electric charges is also weird. So, imagine in the room you're sitting there's a giant north pole of a magnet to your left and a giant south pole to your right. That means there's a strong magnetic field going from left to right and I'm going to be assuming that this field is uniform (ie, it's the same strength at every point in the room). Now imagine you have a ball with a positive charge on it. If it's sitting still the magnetic field will do nothing to it. Now, if you throw it forward you know where the magnetic field will push the ball? Upwards into the ceiling! Magnetic fields are weird.
Part 2: The apparent problem
But there is no such thing as an absolute measure of velocity. When we measure how fast something is going we measure it compared to the Earth, which we treat as stationary. But when we give the speed of the Earth we give it as a figure of how fast it's going around the Sun and treat that as stationary. But the Sun isn't stationary either, it's moving through the Milky Way the entire time.
We can only ever say how fast something is going relative to something else. That something else we call a reference frame. Like I said the usual reference frame is the Earth. But reference frames are arbitrary. We can pick any reference frame and it makes no difference to the laws of physics (unless the reference frame is accelerating but let's not get into that).
So remember when I said magnetic fields only affect charges that are moving? So lets go back to the example of a ball of charge going forward with magnets to either side of the room. In the reference frame of the room the ball moves forward through the magnetic field and as I said it flies upwards. In the reference frame of the ball it's not even moving so therefore it shouldn't feel any force from the magnetic field and nothing should happen. And no, the charge won't feel the field moving against it if it's a uniform field.
By the classical laws of physics when you do the calculations from one reference frame on thing happens and when you do it in another reference frame something else happens. This is not supposed to happen. So now I'm finally getting to the point of this. What is happening? Well I assume you've all heard of Einstein's Special Theory of Relativity, but I doubt most of you know it was devised to explain
Part 3: ****ing magnets, how do they work?
So imagine now we have a ball of electric charge like in the earlier example but this time we have it next to a wire with a current going through it. For simplicity we shall imagine the wire as being like a tube with two things in it: Electrons moving all with the same speed along the wire (electrons are negatively charged) and stationary ions (positively charged). Here's a diagram:
The negative electrons and positive ions are evenly spaced and our ball of positive charge feels no overall electric force from them. There is also a magnetic field present but it doesn't affect our ball as it's currently stationary. So lets say the ball starts to move. For simplicity I will assume the ball moves to the right at the same speed as the electrons (hence there will be no relative motion between the ball and the electrons). We know in the reference frame where the wire is stationary the ball will feel a force from the magnetic field (in this case it will be pushed down and away from the wire). But what happens in the frame where the ball is stationary and the wire is moving? Here's a new diagram:
So we have a stationary positive charge, stationary electrons and ions moving to the left now. You may have noticed that there are now more ions in the picture than electrons. This is not a mistake. Special relativity is an interesting thing. You've probably heard of the twin paradox. It's about how in special relativity that time moves slower for faster moving objects. There is a less known effect called length contraction where if something is moving towards or away from you, it is shorter based on how fast it's moving.
The individual electrons going along the wire in the first diagram are length contracted too but it doesn't affect the distribution of charge, but when the wire starts moving relative to the ball its length gets contracted and as the wire is made of these positive ions the ions get smushed closer together. Now there are more positive charges near our ball than negative charges and since the ball is also positive it will be pushed away from the wire, downward, just like it was in the reference frame where the wire was stationary and the ball was moving.
This is what magnetism is. As far as the charge is concerned it never feels a magnetic field, just an electric one. Magnetic fields are electric fields in a different reference frame due to special relativity. So now you know how magnets work and scientists no longer have to be getting you pissed!
