Astronomy and Astrophysics – Astrophysics
Scientific paper
2003-01-10
Astrophys.J. 585 (2003) L77-L80
Astronomy and Astrophysics
Astrophysics
Title change. One reference added. Final version accepted by ApJL
Scientific paper
10.1086/374350
We present a method of directly testing whether time continues to have its usual meaning on scales of <= t_P = sqrt(hbar G/c^5) ~ 5.4E-44 s, the Planck time. According to quantum gravity, the time t of an event cannot be determined more accurately than a standard deviation of the form sigma_t/t = a_o (t_P/t)^a, where a_o and a are positive constants ~1; likewise distances are subject to an ultimate uncertainty c \sigma_t, where c is the speed of light. As a consequence, the period and wavelength of light cannot be specified precisely; rather, they are independently subject to the same intrinsic limitations in our knowledge of time and space, so that even the most monochromatic plane wave must in reality be a superposition of waves with varying omega and {\bf k}, each having a different phase velcocity omega/k. For the entire accessible range of the electromagnetic spectrum this effect is extremely small, but can cumulatively lead to a complete loss of phase information if the emitted radiation propagated a sufficiently large distance. Since, at optical frequencies, the phase coherence of light from a distant point source is a necessary condition for the presence of diffraction patterns when the source is viewed through a telescope, such observations offer by far the most sensitive and uncontroversial test. We show that the HST detection of Airy rings from the active galaxy PKS1413+135, located at a distance of 1.2 Gpc, secures the exclusion of all first order (a=1) quantum gravity fluctuations with an amplitude a_o > 0.003. The same result may be used to deduce that the speed of light in vacuo is exact to a few parts in 10^32.
Hillman Lloyd W.
Lieu Richard
No associations
LandOfFree
The phase coherence of light from extragalactic sources - direct evidence against first order Planck scale fluctuations in time and space does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The phase coherence of light from extragalactic sources - direct evidence against first order Planck scale fluctuations in time and space, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The phase coherence of light from extragalactic sources - direct evidence against first order Planck scale fluctuations in time and space will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-583797