outline the essential problem with light, the aether and the principle of relativity. (1 Viewer)

[some one body]

could someone help me out with this question, it's from the physics DOT POINT book:

dot point:describe the significance of the assumption of einstiens assumption of the constancy of the speed of light

Question: outline the essential problem with light, the aether and the principle of relativity.

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the book doesn't give an answer to the question only a summary to the dotpoint

thanks in advance

 

[annabackwards]

Re: outline the essential problem with light, the aether and the principle of relativ

Light --> they assumed it needed a medium to travel through like all other known waves back then for eg sound.

Aether --> was the proposed medium light travels through. It had many properties such as is being invisible, elastic enough to propagate light waves and that it permeated through everythying. However, the Michelson Morely experiment came up with a Null result no matter how many times they repeated it. This was the problem.

Principle of relativity --> gave an explanation for the null result as it said light traveled through a vaccuum, Einstein said aether's existence was "superfluous ".

 

[some one body]

Re: outline the essential problem with light, the aether and the principle of relativ

ty

 

[annabackwards]

Re: outline the essential problem with light, the aether and the principle of relativ

No worries

 

[richman92]

Re: outline the essential problem with light, the aether and the principle of relativ

if the aether existed then light made from different objects traveling in different directions in the aether would have different velocites relate to the aether, as a result, the observer could measure and determine they are moving in a inertial frame of reference . That violates the priciple of relativity since it states that a constant motion cannot be detected without refering to a fixed point outside the frame

 

[zaxmacks]

Re: outline the essential problem with light, the aether and the principle of relativ

Light --> they assumed it needed a medium to travel through like all other known waves back then for eg sound.

Aether --> was the proposed medium light travels through. It had many properties such as is being invisible, elastic enough to propagate light waves and that it permeated through everythying. However, the Michelson Morely experiment came up with a Null result no matter how many times they repeated it. This was the problem.

Principle of relativity --> gave an explanation for the null result as it said light traveled through a vaccuum, Einstein said aether's existence was "superfluous ".

A more accurate way of describing it is that they created the aether model because the constant c came up a lot in Maxwell's equations, and Galilean relativity states that all motion is relative, so the constant speed of light had to be relative to something. They made it so that light was a constant relative to the aether. I think they already knew that EM waves could propagate in a vacuum, because Maxwell described light as alternating electric and magnetic fields, perpendicular to each other.

Relativity did away with the aether model by proposing that light is relative to all frames of reference, not the all pervasive aether, and it accomplished this by introducing mass/time dilation and length contraction, to accommodate the constant velocity of light.

 

[Pwnage101]

Re: outline the essential problem with light, the aether and the principle of relativ

Principle of relativity --> gave an explanation for the null result as it said light traveled through a vaccuum, Einstein said aether's existence was "superfluous ".

Be careful - the Principle of Relativity did not state this, it states that, regarding an inertial frame of reference, without rteference to an outside frame of reference, one cannot determine whther theya re moving with constant velocity, or no motion at all.

This predates Einstein (although it was affirmed by him in his "statement" part of his Special Theory of Relativity), in fact it predates (and was generally accepted by) Newton and Galileo, but probably not as far back as aristotle.

Regarding outlining the essential problem with light, the aether and the principle of relativity.

Well the aether is 'superfluous', as stated above (and by Einstein), so there isn't so much a problem with it.

In answering this dot point, look into Einstein's thought experiment, with him asking the question "if i am sitting on a train tarvelling at c, will i see myereflection in a mirror i hold up infront of me?" [most textbooks will have this]. Also, i recommend having a look at the 2008 CSSA Trial (Question 19? from memory) and solutions, if you have access to it.

 

[zaxmacks]

Re: outline the essential problem with light, the aether and the principle of relativ

This predates Einstein (although it was affirmed by him in his "statement" part of his Special Theory of Relativity), in fact it predates (and was generally accepted by) Newton and Galileo, but probably not as far back as aristotle.

It pre-dates Galileo? I was pretty certain that when he came up with his theory of relativity, he wasn't building on previous work.

 

[k02033]

Re: outline the essential problem with light, the aether and the principle of relativ

Be careful - the Principle of Relativity did not state this, it states that, regarding an inertial frame of reference, without rteference to an outside frame of reference, one cannot determine whther theya re moving with constant velocity, or no motion at all.

Principle of relativity states that all laws of physics are identical in all inertial frames of reference.
What you have stated is a consequence of principle of relativity.
It was Einstein's belief in the principle of relativity that led him to propose his relativistic theory.
(he believed that the universe is elegant so he enforced this uniformity)

 

[warezfan]

Re: outline the essential problem with light, the aether and the principle of relativ

There is no problem with the aether. It's perfectly plausible that such a thing exist. Even with the null result it doesn't disprove the existence of the aether, it just proves that aether don't behave like the way MM thought it does.

 

[Pwnage101]

Re: outline the essential problem with light, the aether and the principle of relativ

It pre-dates Galileo? I was pretty certain that when he came up with his theory of relativity, he wasn't building on previous work.

He definitely was the first to formally state it, but i read somewhere that that the ideas behind it does pre-date him.