In reply to Eric Walker's message of Tue, 1 Jul 2014 21:23:03 -0700: Hi, That the estimates for the time taken in the Sun vary between 10000 & 170000 years, then this tells me that such estimates are not on a very sound footing. If the difference is a factor of 17 for a constant star like the Sun, then I'm surprised that they only got if wrong by a factor of 2 for the supernova.
>On Tue, Jul 1, 2014 at 1:51 PM, <mix...@bigpond.com> wrote: > >The delay is caused by the photons trying to fight their way through the >> plasma >> and gas. Even after the explosion has taken place, some of them still have >> to >> fight their way through the expanding plasma cloud ... > > >Note also that in a star like the sun, the estimated time for radiation to >reach the surface is between 10,000 and 170,000 years [1]. I'm not sure >exactly how this time is apportioned for different starting points from the >center. But nonetheless if these values can be compared to the 4 hour >delay, then we can get a rough estimate of the speedup: > > 10,000 years / 4 hours = 8.76581E7 hours / 4 hours ~ 21,914,531 > >So if you're right about the delay being due to the light traveling slower >in the milieu of the supernova than in a vacuum, even then there's been a >21 million-fold increase in its velocity, which seems reasonable. I >imagine they're measuring the start of the four hours by looking for >radiation from the direction of the source above some minimum intensity? > >Eric Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
