c = 299 792 458 m/s and uncertainty


by DonnieD
Tags: m or s, uncertainty
DonnieD
DonnieD is offline
#1
Feb4-07, 01:19 PM
P: 9
c is 299 792 458 m/s without uncertainty? doesn't work the Heisenberg uncertainty principle for fotons?
Phys.Org News Partner Physics news on Phys.org
Physicists design quantum switches which can be activated by single photons
'Dressed' laser aimed at clouds may be key to inducing rain, lightning
Higher-order nonlinear optical processes observed using the SACLA X-ray free-electron laser
AlphaNumeric
AlphaNumeric is offline
#2
Feb4-07, 02:08 PM
P: 290
The distances typically involved in measuring c are sufficently big that quantum fluctuations are ignored.

Also, the length of 1m is defined by the distance light travels in a certain amount of time. Because of this definition, we're effectively defining light's speed, not measuring it, so it is exact.
Born2Perform
Born2Perform is offline
#3
Feb5-07, 07:24 AM
P: 80
Quote Quote by AlphaNumeric View Post
Also, the length of 1m is defined by the distance light travels in a certain amount of time. Because of this definition, we're effectively defining light's speed, not measuring it, so it is exact.
we define 1m, but we must still measure in how much time light crosses 1m; we measured c but it can be less or more, right?

russ_watters
russ_watters is offline
#4
Feb5-07, 12:14 PM
Mentor
P: 22,001

c = 299 792 458 m/s and uncertainty


No, the meter is defined as the distance light travels in a specified time.

http://www.mel.nist.gov/div821/museum/timeline.htm


Register to reply

Related Discussions
Uncertanty principal and repulsion forces of quark & gluons 2 question High Energy, Nuclear, Particle Physics 1