Science is weird

ríomhaire

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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:
753uh.png


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:



2R3jG.png




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:



qSMql.png




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!
 
That's pretty awesome. I can officially say that I have learned something today.
 
Magenta was always smalltime.
 
We still love you dude, CMYK 4 LIFE.
 
How does this impact upon colourblindness? Does this mean colourblind people only see the TRUE colours? :O
 
How does this impact upon colourblindness? Does this mean colourblind people only see the TRUE colours? :O

Oh... interesting! Does anyone know what typical color blindness entails? What kind of variation are there? I know some can see only a few colors and others have trouble telling the difference between similar colors, but is there a type where their brain is unable to create these "mixtures?"
 
That is pretty cool.

Stupid question: Is brown a color? I know from just messing around that mixing red and green gives something kinda ugly-brownish, but it seems on the spectrum there's no brown either.
 
Oh... interesting! Does anyone know what typical color blindness entails? What kind of variation are there? I know some can see only a few colors and others have trouble telling the difference between similar colors, but is there a type where their brain is unable to create these "mixtures?"
The most common type of colour-blindness is not being able to tell the difference between red and green.
 
The most common type of colour-blindness is not being able to tell the difference between red and green.
* Certain kinds of green and red.

Very few people wouldn't be able to tell which is green and red if they saw the colours of blood and grass, for instance. I am red-green colour-blind, and colours that I sometimes confuse are green-grey, green-yellow, green-brown, green-blue (rarely), yellow-orange, red-pink, red-purple and blue-purple. Confusing red with green or vice versa is very rare, but I guess I confuse colours that contain either of those.

EDIT:
Like this:
800px-Lilac_Flower%26Leaves%2C_SC%2C_Vic%2C_13.10.2007.jpg
That colour can, to me, be either blue, pink or purple. I really have no idea.
 
What about the various lovely shades of brown? Can I get some brown light up in here?
 
So next time I go to mix some paint samples, I need to trick my own brain into thinking that the paint tint isn't there, its only a ****ing illusion?

my mind is officially blown
 
The ability to see colour is due to the cones in your eyes. Real colour is due to a distinct photon of relevant wavelength entering your eye, all other colours means your cones must be getting confused, maybe becuase more then one photon is hitting it at the same time.
 
I'll have to call my friend's little cousin and let her know she only exists in my mind.
 
This is weird indeed, so if our brain didn't make up a color for magenta, what would it look like?
 
Magenta is an invention man. God would never allow such a homosexual color into his majestic color kingdom.
 
This is officially awesome. Mind. Blown.
 
This is weird indeed, so if our brain didn't make up a color for magenta, what would it look like?

Well the Spectrum is only for single-wavelength colors. Since magenta is made up of blue and red wavelengths, your brain might perceive it as bouncing between the two.
 
This is why magenta is commonly used as alpha masks.


Not really.
 
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:



2R3jG.png




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:



qSMql.png




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!
 
Yes Monkey I've read that already. How does it in any way contradict what I said? The title was just to be eye-catching. All I said was magenta does not have a unique wavelength. I also acknowledged that this isn't unusual.
 
Light, just as all electromagnetic perturbations, are waves.
The color in electromagnetic spectrum are plane waves. Plane waves have simple, wavy forms.
Plane waves can be described by different wavelengths, which are the distances between two identical patterns on the wave. For example, violet has a smaller wavelength than red:
Red:
Red.gif

and Violet:
Violet.gif


By superimposing (aka adding up) plane waves of different wavelengths. We can generate all kind of waves. We get magenta by adding red to violet:
Magenta.gif


Obviously, magenta is no longer a plane wave. It is said that magenta has a waveform different from red and violet. Yet, we can still describe magenta's frequency, by counting the distance between two overlapping patterns. The mathematical wavelength of magenta is 2800nm (L.C.F. between 400nm of violet and 700nm of red is 2800nm).
By looking into this, we can understand that our eyes do not discern colors in term of their wavelengths (or frequencies). Rather, our eyes take their waveforms into account as well. Alternatively, we say that our eyes detect certain Fourier components of electromagnetic wave. But I won't get into too much mathematical content of it.
 
The world does not exist
I'm very sorry but the simulation is coming to a close. We've been trying to battle for funding for a very long time now but it has proved to have outlived or been inappropriate for its original purposes. The experiment was flawed from the beginning and observation-based physics were a mistake. The simulation has gotten exponentially slower and slower with scientific progress and observations. We have been told to shut down the project for good and have been given only a few days to do so. For you the simulation will end in a few months. The hardware cost of running has simply become to great. I'm in the process of making a backup and I will see if there is anything that I can do with it.

I'm sorry.
 
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