3 ms·
They don't get 'slowed down' more, they get deflected more. So, the redder light that does reach us had to travel further to get here.
by deciplex 12y ago
They don't get 'slowed down' more, they get deflected more. So, the redder light that does reach us had to travel further to get here.
- Steuard 12y agoThat was one point where I wasn't sure quite how to talk about this. In the back of my mind, I have a sense that "gets deflected more" (meaning "longer distance") is actually referring to the same fundamental process that "gets slowed down more" (in the sense of index of refraction: v=c/n) refers to: either way, the time to pass through the medium is longer than it would take to pass through an equally large vacuum region. But I wasn't quite confident enough to phrase it that way in my main reply.