On: Black hole merger challenges our understanding of black hole formation

[magicalhippo]

> From the perspective of a far-away observer it would look as if time is slowing down as the photons would take increasingly longer to escape.

Photons travel at the speed of light always, that's what Einstein told us.

So rather, the observed energy (frequency) of the photons decreases, and it takes longer between each photon.

At least that's my understanding.