Closest Supernova May Prove Light is Slower Than We Think...or something else
Physicist claims evidence that light is just a little bit slower than we think.
Do you remember 1987? I do. That was the year we detected the closest Supernova in 383 years. It was the first time that advanced human astronomers had a real close view of one. It was very exciting, I even threw a party (no I didn’t). It wasn’t in the Milky Way unfortunately. It was in a nearby (160,000 light years distant) dwarf galaxy called the Large Magellanic Cloud.
The very first indication of a supernova is not a star visibly brightening but the detection of ghost-like particles called neutrinos. These particles have no charge so they can go through everything (even light years of lead) without interacting with it. For that reason, once a star blows its top, neutrinos are the first particles to leave the party. Photons interact with matter much more than neutrinos do so with all that crazy shit going on during a supernova, they’re massively delayed. Photons are kinda like celebrities, everyone has to say goodbye first before they can leave.
As a result, we first detected a burst of neutrinos on that February day in 1987. Theory says that we should have detected the visible light from the explosion about 3 hours later. The weird thing was though, we detected another neutrino burst 4.7 hours later. This one however was followed by light 3 hours later.
Astronomers were in a pickle. Why two neutrino events? They ultimately decided to conclude that the initial burst was an anomaly. Probably unrelated to the supernova. Physicist James Franson looks at it differently however. He thinks the odds of the first burst being a coincidence is 1 in 10,000. He wants to know why the light took 7.7 hours to appear after the initial neutrino detection. He claims it’s because light travels a little more slowly than we think.
He invokes a long known quantum phenomenon called vacuum polarization. When this happens, a photon of light splits into a positron and an electron pair that then quickly recombine. The effect is tiny but if it happens often enough over vast distances, it could have an impact on the velocity of light that could account for the extra 4.7 hour delay.
The impact to science would be seriously non-trivial.
The innumerable calculations astronomers have performed over the years involving the speed of light would have to be re-evaluated and re-calculated. Many theories that have been developed based on observation and assuming the old zippier speed of light would need to be changed or dispensed with.
It’s obviously way too early to recall all the textbooks or to even get a little bit nervous (or excited). There’s tons of alternative explanations that would have to be falsified first (that’s science baby). Perhaps the core of the star collapsed in two stages. Some speculate it may even be a Quark Star. Maybe something mundane in space like dust or a toll booth slowed it down. Perhaps it was just a dumb coincidence after all. It’s hard to say especially since we only have one data point like this from a nearby supernova.
We may need to wait for the next nearby star to go kaplooey. If that does happen, I promise I’ll throw a party.
Image: Artist conception of SN 1987a today
Image credit: ALMA / ESO / NAOJ / NRAO / Alexandra Angelich, NRAO / AUI / NSF.