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If you ever see it go supernova, just remember it went supernova 642.5 years ago...or if it actually does go supernova in your lifetime, you unfortunately not see it.

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In astronomy we typically date events by observation date, not by date at the remote location. The reason is that distance is often poorly known and the estimates are subject to change over time. Time at the solar system barycenter on the other hand can be determined down to the nanosecond and can be compared very well between different observatories.

That and relative velocity between objects can greatly effect what year they would consider the event happening at in their "past" or "future".

I'd say the main reason is that there is no use for the "distance corrected" date. We're all basically in the same place so we can't really mix up the ordering by ignoring the travel time.

Honestly, the best use of this the light delay fact is that you can annoy transient observers by trying to get SN1987A renamed to SN-1678900A or something.

It depends on your frame of reference, there exist frames in which an event and the detection of light from it are simultaneous.

>there exist frames in which an event and the detection of light from it are simultaneous.

At the distance from Earth to Betelgeuse?

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