Supernova study might change how speed of light in vacuum is measured http://b4in.org/j4zy
Einstein’s theories suggest that light can not travel faster than c, a constant equal to the speed of light in a vacuum, which is 299,792,458 metres per second (by definition) or about 186,282.4 miles per second.
All of our standing physical models are based on this assumption, and so far this idea has yet to be proven wrong, despite the neutrino incident from CERN which was later found to be false (at some time neutrinos were found to travel slightly faster than photos, but this was later proven to be due an error in measuring). A study of a 25-year old supernova may lead to a revision of “c”, if its findings are found to be correct.
As you might imagine, the implications are huge since the speed of light in vacuum is used as a constant in all astronomical calculations and observations.
SN 1987A was first observed in February, 1987 when it baffled some scientists with an intriguing anomaly. After a star collapses, traditionally a super nova should immediately emit a burst of neutrinos, followed by a time delayed burst of photons. In the case of SN 1987, this time delay it greater than it should have been as the optical light arrived roughly 7.7 hours after the neutrinos, or 4.7 hours late instead of the expected 3 hours delay.
Why this differences? Three scenarios have been proposed: the optical photons traveled slower than c, they were emitted later than expected, or they originated from a totally separate and irrelevant event.
Typically the last scenario has been used to explain this phenomenon, but James Franson and colleagues at the University of Maryland claim they have found evidence that suggests that light doesn’t actually travel at c in a vacuum – a startling hypothesis which if found true will pose great implications for physics and astrophysics in particular.
When traveling through a medium like water or air, light gets slowed down because it meets all sorts of matter particles.
In the case of the vacuum of space, Franson says a natural property of photons themselves, called “vacuum polarization,” causes a slow down. This causes the photon to split into an electron-positron pair that later recombines back to form a photon.
Even if this split lasts for a moment, though, theory says that this phenomenon causes a gravitational potential between the two particle states.