Vesto Slipher, Christian Doppler & Albert Einstein
[quote=Wikipedia]In 1912, Vesto Slipher discovered that light from remote galaxies was redshifted, which was later interpreted as galaxies receding from the Earth. In 1922, Alexander Friedmann used Einstein field equations to provide theoretical evidence that the universe is expanding. In 1927, Georges Lemaître independently reached a similar conclusion to Friedmann on a theoretical basis, and also presented the first observational evidence for a linear relationship between distance to galaxies and their recessional velocity.[/quote]
[quote=Wikipedia]The Doppler effect or Doppler shift (or simply Doppler, when in context) is the change in frequency of a wave in relation to an observer who is moving relative to the wave source. It is named after the Austrian physicist Christian Doppler, who described the phenomenon in 1842.[/quote]
[quote=Wikipedia]In 1905 Albert Einstein postulated from the outset that the speed of light in vacuum, measured by a non-accelerating observer, is independent of the motion of the source or observer. Using this and the principle of relativity as a basis he derived the special theory of relativity, in which the speed of light in vacuum c featured as a fundamental constant, also appearing in contexts unrelated to light.[/quote]
The Doppler effect, by itself, is unable to distinguish actual motion of the galaxies away from each other and the expansion of the universe as in the space between galaxies is increasing. Insofar as the Doppler effect is concerned the galaxies can be treated as actually moving away from each other.
The Problem:
1. From Doppler effect measurements, some galaxies are "moving" at or faster than light speed.
2. Nothing can either travel at or faster than light.
The solution:
Space is expanding. The "motion" of galaxies is a mirage.
Issue
An empirical finding that indicates motion (the Doppler effect) is being treated as a mere illusion simply to prevent the collapse of a theory (Einstein's theory of relativity).
Attempting to be funny
Next time you get pulled over by cops for speeding (speed guns use the Doppler effect) ask them how they could tell you were moving at all let alone breaking a speed limit?
Please discuss.
[quote=Wikipedia]The Doppler effect or Doppler shift (or simply Doppler, when in context) is the change in frequency of a wave in relation to an observer who is moving relative to the wave source. It is named after the Austrian physicist Christian Doppler, who described the phenomenon in 1842.[/quote]
[quote=Wikipedia]In 1905 Albert Einstein postulated from the outset that the speed of light in vacuum, measured by a non-accelerating observer, is independent of the motion of the source or observer. Using this and the principle of relativity as a basis he derived the special theory of relativity, in which the speed of light in vacuum c featured as a fundamental constant, also appearing in contexts unrelated to light.[/quote]
The Doppler effect, by itself, is unable to distinguish actual motion of the galaxies away from each other and the expansion of the universe as in the space between galaxies is increasing. Insofar as the Doppler effect is concerned the galaxies can be treated as actually moving away from each other.
The Problem:
1. From Doppler effect measurements, some galaxies are "moving" at or faster than light speed.
2. Nothing can either travel at or faster than light.
The solution:
Space is expanding. The "motion" of galaxies is a mirage.
Issue
An empirical finding that indicates motion (the Doppler effect) is being treated as a mere illusion simply to prevent the collapse of a theory (Einstein's theory of relativity).
Attempting to be funny
Next time you get pulled over by cops for speeding (speed guns use the Doppler effect) ask them how they could tell you were moving at all let alone breaking a speed limit?
Please discuss.
Comments (12)
You can't claim that the earth is "fixed" using the Doppler effect or any other effect for that matter for the possibility remains that the earth's expansion rate and the relative motion between two objects cancel each other out - like walking on a treadmill or hamsters in a hamster wheel.
Hi Fool. I'm not going to get into the physics so much, more the history. But one thing to mentally separate is a particular cosmological model from the theory that generates it.
General relativity itself is consistent with a static universe, a collapsing universe, an expanding universe, whatever. The particular cosmological model Einstein was responsible for was a static universe. Far from twisting and bending to make empirical evidence fit theory, Einstein referred to the (empirically, but wrongly, derived) value for the cosmological constant he used as his "biggest blunder".
GR itself was unmolested by the expanding universe. It was just that particular model that had to be thrown out.
[1] Isn't that a problem? If a theory is compatible with "whatever", does it even matter that there's a theory at all?
[2] I don't think it's a blunder :point: Rise, Fall, and Comeback of the Cosmological Constant.
[3] Begging the question. The Doppler shift demonstrates that some objects (galaxies to be specific) are travelling at or faster than light speed. The reason why cosmologists posited an expanding universe was precisely because they didn't want to or were afraid to go against Einstein's theory of relativity. Is this how physics is going to be done? Every time we encounter an observation that contradicts GR, we invent an new theory that proves that the observation never actually falsified GR?
We could've followed a similar protocol with Mercury's orbit when it couldn't be explained by Newtonian physics?
[1] Nope
[2] No offense but I'll take Einstein over yourself as an authority on relativity :D
[3] My previous post treats this.
I'm using reason, you've put your faith in authority (Einstein). I'm 100% certain Einstein would've disapproved.
:smile: So the rule is if you disagree with someone, that someone is being irrational. I get it!
Quoting Kenosha Kid
You've missed the point, haven't you?
:rofl: You make me laugh!