Cheap Astronomy - Dear CA # 133: Why It's Always C
Published: April 15, 2026
Duration: 14:40
Cheap Astronomy investigates why light moves at light speed in a vacuum.
Hosted by Steve Nerlich.
Shining a light!
Dear Cheap Astronomy – Why does a photon travel at speed c, part1
It may sound a bit strange to ask why light travels at the speed of light, but that's because c isn't really the speed of light – it's really a measure of the relationship between distance (or space) and time. It's become customary to call c the speed of light, but in reality light moves at different and slower speeds through air...