No. 29: Sep-Oct 1993
Astronomer A.P. Fairall has reported an "impossible" physical situation -- a strong scientific anomaly. It seems that a Seyfert galaxy (a very low-luminosity quasar) emits forbidden spectral lines that vary in intensity about every 30 minutes. It is not the "forbidden" character of the spectral likes that disturb the astronomers. ("Forbidden" simply means "improbable" in spectroscopy!) Rather, it is the half-hour variations that pose the dilemma. This is because most astronomers are convinced that the said forbidden lines are emitted by regions of the quasar that are 100-10,000 light years across.
A disturbance or physical change leading to a variation in intensity, even travelling at the speed of light, could not begin to move across this huge region in half an hour. Yet, the changes in intensity seem to be there, inferring a physical change that travels perhaps a million times faster than physics permits. Variations in intensity decades long would be acceptable, but half an hour is out-of-the-question! The author of this referenced comment in Nature believes that the observational procedures employed must be at fault.
(Gaskell, C. Martin; "Spectra That Defy Explanation," Nature, 304:212, 1983.)
Comment. This possible anomaly is closely related to the so-called superluminal velocities also observed in quasars, in which physical effects seem to travel faster than light. Apparently something is very wrong in our model of a quasar, or our distance scale, or even our basic physics.