Photons travel, and, as far as we can tell, have always traveled, at the same constant speed in a vacuum. It's "so constant" that even if you try to fly away fr

Photons travel, and, as far as we can tell, have always traveled, at the same constant speed in a vacuum. It's "so constant" that even if you try to fly away from a photon at nearly c, it will still hit you with velocity c. Even if you try to fly into it at nearly c, it will still hit you with velocity c. No time dilation, not even from black holes, can slow down (or speed up) light. Instead, the light's frequency from your perspective is what changes. This is where redshift/blueshift comes from. (Imagine the waveform being compressed/stretched out.) This is one of the crucial insights of special relativity.