[Omitting a longish rant, that once we give up Lorence invaraiance we do no longer know anything.] AFAIK it is essentially the fine tuning argument. So not really generic but in the absence of a good argument a reasonable default value.
> What's this timescale have to do with it?
The timescale was essentially meant illustrative, so a short everyday timescale compared to gigayears. ( And it is conservative, in the sense that I do not need to remember the exact details of a GRB spectra to use this one ;)
[Omitting a longish rant, that once we give up Lorence invaraiance we do no longer know anything.] AFAIK it is essentially the fine tuning argument. So not really generic but in the absence of a good argument a reasonable default value.
> What's this timescale have to do with it?
The timescale was essentially meant illustrative, so a short everyday timescale compared to gigayears. ( And it is conservative, in the sense that I do not need to remember the exact details of a GRB spectra to use this one ;)