The Math Forum

Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Math Forum » Discussions » sci.math.* » sci.math

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Replies: 4   Last Post: Nov 19, 2013 12:27 PM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Pentcho Valev

Posts: 6,212
Registered: 12/13/04
Posted: Nov 17, 2013 8:10 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply
John Stachel: "How can it happen that the speed of light relative to an observer cannot be increased or decreased if that observer moves towards or away from a light beam? Einstein states that he wrestled with this problem over a lengthy period of time, to the point of despair."

If a light source emits a series of pulses the distance between which is d = 300000 km, then an observer moving with speed v = 100000 km/s towards the source measures the frequency of the pulses to be (relativistic corrections are ignored, for the sake of simplicity):

Rational science: f' = (c + v)/d = (300000 + 100000)/300000

Relativity: f' = (c + v)/d = (300000 + 100000)/300000

The speed of the pulses relative to the observer is:

Rational science: c' = (f')d = 400000 = (4/3)c

Relativity: c' = (f')d' = 300000 = c

where d' is the procrusteanized distance between the pulses guaranteeing the equality c'=c, Divine Einstein, yes we all believe in relativity, relativity, relativity. In this particular case the distance is contracted:

d' = cd/(c + v) = (3/4)d

but it could be stretched as well - e.g. if the observer were moving with speed v AWAY from the source:

d' = cd/(c - v) = (3/2)d

Clearly relativity is invincible - starting from 1889 (FitzGerald performs the first length contraction), lengths always contract or stretch so that the constancy of the speed of light, c'=c, simply cannot be wrong. And once the irrational takes over and becomes official science, rational opposition disappears very quickly - nowadays there can be nothing more reasonable than shrinking or stretching lengths as long as the speed of light remains constant, Divine Einstein, yes we all believe in relativity, relativity, relativity.

Pentcho Valev

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© The Math Forum at NCTM 1994-2018. All Rights Reserved.