Is light a wave or a straight line before it hits something?

[Nugatory]

Astronauts are not ''blind'' in space, in space there is no air. It is not so obvious that light propagates in space

Ahhh... How do you think the light of distant stars makes it to your eyes, if that light did not propagate through the empty space between star and earth? Electrical and magnetic fields can exist in a vacuum, in air, or in any other matter, and where the fields exist there can be waves in them.

How do we know it is not only a wave when light is being interfered with?

We don't. We do know that the laws of electricity and magnetism, which were formalized in Maxwell's equations more than 150 years ago, say that there will be waves in the electrical and magnetic fields even when nothing is interacting with the propagating waves. We do know that centuries of observations of the behavior of light agree with the answers we get when we calculate what would happen if light is in fact a wave as described by these laws of electricity and magnetism. We do know that no one has ever been able to come up with any alternative that correctly describes the observed behavior of light. Putting all that together... The only sensible theory we have says that light is a wave in the electrical and magnetic fields and all the available evidence supports this explanation. That's as good as it ever gets in science.

How do we know that '''white light'' is really a mixture of frequencies?

You construct a light source that generates electromagnetic radiation with an appropriate mixture of frequencies, activate it, and see if the light that comes out is white. It is. Then you suppress some of the frequencies to get a different mixture, see if the light is still white. It isn't. That doesn't prove that white light is a mixture of frequencies, but it does support that hypothesis and it shifts the burden of proof to people who claim that they have some plausible alternative explanation.

Could a prism simply not just be a result of a Center of pressure (C.O.M), offset, the angular displacement of the prisms surface having effect on the radiation pressures force by angular distance travelled?

Can we use that model to correctly calculate the deflection of light of different colors (don't forget the stuff outside the visible spectrum, from radio waves to hard x-rays) when it encounters materials of different composition? And that agrees with all the other observations of light that we've been able to make over the centuries? The wave theory does all those things, and a lot more besides. For example...

What mechanism would a prism have to separate a mixture of incident frequencies to from individual outputs of a wavelength?

Set up the wave equation for waves of various frequencies intersecting an angled surface, solve it, see you get. If you do the calculation right, you'll get a result that says the waves of different frequencies are deflected by different angles. Now check those calculated results against the behavior of a real prism. The results will agree to within the limits of your measurement accuracy.

The real takeaway here should be that is pretty much impossible to replace (or even improve) a theory before you understand what it does.

 

[Heretoignore]

Set up the wave equation for waves of various frequencies intersecting an angled surface

I think I am saying the same thing but alternatively considering the radiation pressure on the angled surface. When light is ''compressed '' at its slowest passing rate we observe a wave=blue do we not?

And when light passes at its faster spectral rate and is more decompressed we observe a wave=red do we not?

Has seen in the Doppler effect.

And when light is as its constant, we observe a constant clarity? (white light)

So when we observe spectral content of emr, is this a temporal offset of the constant?

The word rather than propagate I needed to use is bottlenecking.

1. something that holds up progress, esp of a manufacturing process

 

[ogg]

@Nugatory. I'm doubtful that "hard vacuum" has EVER been created in the lab. Its a trivial point, but last I heard (long ago, admittedly) our very best lab vacuums were orders of magnitude dirtier than space. Your statement of course isn't false (whether I'm correct or not) since you didn't define "hard" vacuum. Last I heard, we need to get 100,000 miles or so away from Earth, to get a reasonably "clean" vacuum, and go out a hundred+ AU to get away from the Solar Wind, and then tens of thousands of lightyears to get to intergalactic space, and finally out millions of lightyears to get into space having density below the average density of the Universe (the Void).

The OP has been well answered, but I'd like to try to address the question in a different way: Thinking "Light is a particle" is wrong. Thinking "Light is a wave" is wrong. Light is light. We can DESCRIBE light AS IF it were a wave in some situations, and AS IF it were a particle in other situations (and as neither or both in others). We usually think of groups of photons as a wave or waves and single photons as particles (or quanta) (photons are the quanta of emr - we don't call them particles of emr (usually) because calling them 'quanta' helps distinguish them from the mathematical point-like particles in beginning Physics texts, and distinguishes them from the macroscopic stuff we see (and touch) all around us. A quantum mechanical particle is very very different from a rock or a grain of sand.) So, here is the question: if thinking "light is a wave/particle" is wrong, why do we describe it that way? The answer is: It is useful to think of light as a wave/particle in some situations because the mathematical treatment becomes much simpler. Its not clear, but is seems as if the OP thinks that the wave nature of light involves the path of a quanta to be wavy in space, moving to the left, then to the right (or up and down, or backwards and forwards). This is wrong. The wave nature of light is about the electric field and magnetic field oscillations and the way their change with time (or distance). Think of the pressure in a car's piston chamber. The pressure is a periodic function (a wave, although not a sine wave). So describing the pressure profile as a wave is accurate, but doesn't mean the car or the piston chamber or the gasses in the chamber are weaving down the road like a wave. So, I point out two errors: one: the MOTION of a photon is not ever "wave" motion; two: thinking of light at anyone instant as either a wave or a particle is wrong. Light is light. I also want to add that "light" is a word with many meanings. In physics it may mean "a photon", it may mean a group of photons, or it may mean a (very large) stream of photons. The (mathematical) models we use to deal with these different meanings are often quite different. We usually choose the model so that whatever problem we are working with can be handled most easily.

 

[Heretoignore]

@Nugatory. I'm doubtful that "hard vacuum" has EVER been created in the lab. Its a trivial point, but last I heard (long ago, admittedly) our very best lab vacuums were orders of magnitude dirtier than space. Your statement of course isn't false (whether I'm correct or not) since you didn't define "hard" vacuum. Last I heard, we need to get 100,000 miles or so away from Earth, to get a reasonably "clean" vacuum, and go out a hundred+ AU to get away from the Solar Wind, and then tens of thousands of lightyears to get to intergalactic space, and finally out millions of lightyears to get into space having density below the average density of the Universe (the Void).

The OP has been well answered, but I'd like to try to address the question in a different way: Thinking "Light is a particle" is wrong. Thinking "Light is a wave" is wrong. Light is light. We can DESCRIBE light AS IF it were a wave in some situations, and AS IF it were a particle in other situations (and as neither or both in others). We usually think of groups of photons as a wave or waves and single photons as particles (or quanta) (photons are the quanta of emr - we don't call them particles of emr (usually) because calling them 'quanta' helps distinguish them from the mathematical point-like particles in beginning Physics texts, and distinguishes them from the macroscopic stuff we see (and touch) all around us. A quantum mechanical particle is very very different from a rock or a grain of sand.) So, here is the question: if thinking "light is a wave/particle" is wrong, why do we describe it that way? The answer is: It is useful to think of light as a wave/particle in some situations because the mathematical treatment becomes much simpler. Its not clear, but is seems as if the OP thinks that the wave nature of light involves the path of a quanta to be wavy in space, moving to the left, then to the right (or up and down, or backwards and forwards). This is wrong. The wave nature of light is about the electric field and magnetic field oscillations and the way their change with time (or distance). Think of the pressure in a car's piston chamber. The pressure is a periodic function (a wave, although not a sine wave). So describing the pressure profile as a wave is accurate, but doesn't mean the car or the piston chamber or the gasses in the chamber are weaving down the road like a wave. So, I point out two errors: one: the MOTION of a photon is not ever "wave" motion; two: thinking of light at anyone instant as either a wave or a particle is wrong. Light is light. I also want to add that "light" is a word with many meanings. In physics it may mean "a photon", it may mean a group of photons, or it may mean a (very large) stream of photons. The (mathematical) models we use to deal with these different meanings are often quite different. We usually choose the model so that whatever problem we are working with can be handled most easily.

Thank you for the interesting post, but what if we considered that the Sun releases an isotropic outward quanta ''stream''? a continuous flow of quanta with no spacing between quanta, would this not give an illusion of a wave and a speed?
All mass being ''submerged'' in the isotropic quanta ''stream'' and effectively creating ''observer effect'' on the constant??

 

[nasu]

The illusion of a speed? What would you mean by this?

 

[berkeman]

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