Re: When can we use special relativity?


"Tom Roberts" <tjroberts137@xxxxxxxxxxxxx> wrote in message
news:7hQah.16667$6t.3934@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
fitz wrote:
When can we use special relativity?

SR is strictly valid only in a flat Lorentzian manifold with the topology
of R^4. This of course is a very poor model of the world we inhabit.

But physics is not math, and we often use approximations. SR is
approximately valid when the curvature of the manifold is negligible over
the region of interest compared to one's measurement accuracy. That is, if
gravity is negligible (or compensated for), SR can probably be used. So,
for instance, most tabletop experiments (for which the components are
supported against gravity) can be analyzed using SR [#]. Virtually all
elementary particle experiments can likewise be analyzed using SR (mainly
because individual events have durations of only a few dozen nanoseconds).
This is only a loose characterization, and when in doubt a proper GR
computation or estimate should be performed.

[#] But not all -- a fiber gyroscope fits on a table but
can measure the rotation of the earth; the Eot-Wash
apparatus fits on a table but is sensitive enough to
respond to the gravity of the sun with exquisite precision.

Hmm.. about the fiber gyroscope, SRT is sufficient. And about Eot-Wash,
that's neat! Do you have a reference?

Thanks,
Harald


.

Relevant Pages

  • Re: When can we use special relativity?
    ... SR is strictly valid only in a flat Lorentzian manifold with the topology of R^4. ... That is, if gravity is negligible, SR can probably be used. ... Virtually all elementary particle experiments can likewise be analyzed using SR. ...
    (sci.physics.relativity)
  • SR is approximately valid, physics is not math.
    ... | SR is strictly valid only in a flat Lorentzian manifold with the ... | topology of R^4. ...
    (sci.physics.relativity)