3 ms·

The frame of reference is us, now. And "slow" means the maximum speed of a photon was slower back then. The "back then" that we are now just observing from our

• cvoss 3y ago
  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.
• pdonis 3y ago
  > slow" means the maximum speed of a photon was slower back then No, it doesn't. The laws of physics, including the speed of light, were the same then as now. The article's description is seriously misleading. The effect it is talking about is only an appearance due to the redshift of light from back then. It does not mean that anything was "really" happening slower.
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• Vox_Leone 3y ago
  >The frame of reference is us, now. I was about to write that myself. It's our frame of reference vs distant massive frame of reference. It is a quite natural explanation.