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Was Einstein wrong all along? Controversial theory suggests the speed of light is SLOWER than we think

Einstein claimed speed of light in a vacuum is 186,282 miles per second
But James Franson from Maryland University believes it is slower than this
In 1987, light particles of a supernova arrived 4.7 hours later than expected
Dr James Franson suggests this may be because of 'vacuum polarisation'
This, he claims, had a gradual, but significant, impact on speed of photons
If he is correct, it means scientists have to recalculate everything from our distance to the sun to some of the most distant objects in other galaxies

In 1987, light particles of a supernova arrived 4.7 hours later than expected

That one is a little far fetched to be believed. We know exactly when neutrinos from the 1987A supernova passed through earth (they were detected by several underground neutrino detector experiments), but I doubt we know exactly when photons from 1987A arrived. The moment that Canadian astronomer FIRST noticed 1987A visually from that observatory in Chile doesn't count as the moment the photons arrived.