SN_1987 shows that neutrinos travel at the speed of light almost all of the time but does not rule out that they might have velocities that exceed that of light very briefly at the moment they’re generated. See here for more. Note that I, like the author of the post I’ve linked, do not believe that this finding will stand up. It’s just that if it does stand up, it will be because the constant velocity assumption is wrong.
SN_1987 shows that neutrinos travel at the speed of light almost all of the time but does not rule out that they might have velocities that exceed that of light very briefly at the moment they’re generated. See here for more. Note that I, like the author of the post I’ve linked, do not believe that this finding will stand up. It’s just that if it does stand up, it will be because the constant velocity assumption is wrong.