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In the ABC News video New space discovery has astronomers buzzing at about 02:30 Dr. Hakeem M. Oluseyi explains that the shortness of FRBs (before dispersion) suggests a compact source size and illustrates this by using the Sun as an example.

I'd never though about this until just now, but the radius of the Sun is indeed about 2.3 light-seconds. It takes light from the edge of the Sun's disk over 2 seconds longer to reach us than light from the central area.

Are there any ways in which this light time difference is noticeable, or needs to be taken into account?

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    $\begingroup$ I wouldn't expect so, since that would require things to happen simultaneously at widely-separated points on the Sun's surface, and there's not a good way for that to happen. (The obvious way would be for something to happen in the center of the sun, and propagate out to reach the whole surface at once, but there's too much variable Sun-stuff in the way.) However, I am by no means an expert. $\endgroup$ – Trip Space-Parasite Feb 8 at 16:28
  • $\begingroup$ @TripSpace-Parasite see comments here for a possible example of something that can "happen simultaneously at widely-separated points on the Sun's surface". $\endgroup$ – uhoh Feb 8 at 20:18
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    $\begingroup$ I stand (well, slouch) corrected! $\endgroup$ – Trip Space-Parasite Feb 8 at 21:29
  • $\begingroup$ @TripSpace-Parasite I'm by no means an expert either. It's speculation at this point but I have a hunch it will pan out. $\endgroup$ – uhoh Feb 8 at 21:50
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    $\begingroup$ No, no, it's a good point. Helioseismology is a thing, so obviously waves can propagate across and through the Sun pretty well. I hadn't thought of that. $\endgroup$ – Trip Space-Parasite Feb 8 at 23:55

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