Speed of light in ether

  • #1
Luis Babboni
10
1
Hi people!

May be this could be an historical question.
Before Einstein, it is suppoused that speed of light in ether is always the same, I´m right?
I mean, if observer O is at rest respect ether and observer O´ is moving respect ether and O´ send a photon to O, the speed at which that photon arrives O (measured by O) is c cause, as I said, O is at rest respect ether? That is that the speed of O´, the source of the photon, must not be added to c.

Thanks for comment.
 

Answers and Replies

  • #2
Nugatory
Mentor
14,041
7,681
If you're going to talk about what physicist believed before 1905 you will have to pretend that you never heard the word 'photon"... but you can substitute the more appropriate phrases "flash of light" or "light signal" and your question still works.

And with that correction the answer is "yes". However, this answer is inconsistent with the negative result of Michelson-Morley experiments, and that's how we ended up where we are.
 
Last edited:
  • Like
Likes vanhees71, Ibix and berkeman
  • #3
Luis Babboni
10
1
Thanks Nugatory! :-)
 
  • #4
DrStupid
2,167
500
Before Einstein, it is suppoused that speed of light in ether is always the same, I´m right?

According to the classical ether theory the speed of light was always the same in the rest frame of the ether (in absence of matter).
According to Maxwell the speed of light was the same in every frame of reference (again in absence of matter).
 
  • #5
Luis Babboni
10
1
"According to Maxwell the speed of light was the same in every frame of reference (again in absence of matter)."
Good point!
Thanks DrStupid!
 
  • #6
Nugatory
Mentor
14,041
7,681
Mentor's note: Several off-topic posts about the Lorentz ether theory have been removed from this thread. Despite sharing the word "ether", this is a substantially different theory (not falsified by Michelson-Morley experiments) than historical ether theory that the original poster was asking about.

Even if it were on topic in this thread, we generally do not allow discussion of the LET: https://www.physicsforums.com/insights/pfs-policy-on-lorentz-ether-theory-and-block-universe/
 
  • #7
David Lewis
842
251
According to Maxwell the speed of light was the same in every frame of reference (again in absence of matter).
Does that mean everything is at rest with respect to a flash of light or light signal?
 
  • #8
Ibix
Science Advisor
Insights Author
9,711
9,963
Does that mean everything is at rest with respect to a flash of light or light signal?
No. It turns out to mean (coupled with the principle of relativity) that there is no such thing as "with respect to light". You can't define a frame where light is at rest.
 
  • Like
Likes David Lewis
  • #9
Luis Babboni
10
1
Mentor's note: Several off-topic posts about the Lorentz ether theory have been removed from this thread. Despite sharing the word "ether", this is a substantially different theory (not falsified by Michelson-Morley experiments) than historical ether theory that the original poster was asking about.

Even if it were on topic in this thread, we generally do not allow discussion of the LET: https://www.physicsforums.com/insights/pfs-policy-on-lorentz-ether-theory-and-block-universe/

The reason I asked about it is cause in our class we have a first practice that ask we what previous to Einstein physics thought about some things and then in following practices we must found what after Einstein physics thinks about the same things.
 
  • #10
m4r35n357
654
148
The reason I asked about it is cause in our class we have a first practice that ask we what previous to Einstein physics thought about some things and then in following practices we must found what after Einstein physics thinks about the same things.
There is some discussion on the history leading up to Special Relativity in this chapter of this book.
 
  • #11
Luis Babboni
10
1
Thanks!
 

Suggested for: Speed of light in ether

Replies
33
Views
914
  • Last Post
Replies
22
Views
673
  • Last Post
Replies
11
Views
578
  • Last Post
Replies
18
Views
633
  • Last Post
Replies
25
Views
966
Replies
8
Views
464
Replies
2
Views
440
Replies
57
Views
1K
  • Last Post
Replies
29
Views
695
Replies
11
Views
515
Top