Does the observer effect apply to light sources?

Question

A popular thought experiment for explaining how observation affects that which is observed, is to point out that observing an object requires bouncing photons off it, which will affect the object's momentum.
However, what if we are observing photons that are emitted by the object at regular intervals? Whether such photons intersect with a sensor or not does not appear to affect the momentum of the emitter.
How do we reconcile the results of these two thought experiments?

joseph h · Answer

Even if you are observing photons that are emitted from an object, when you detect them, they will still interact with whatever device you are using to do this. So while the momentum of the photons leaving the emitter might not be disturbed, their momentum will be changed when they enter the detector and interact with its constituents.

Answered by joseph h on March 27, 2021

Does the observer effect apply to light sources?

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