Here’s my question explained with a little more detail….
Room #1: Blackout curtains/blinds/shades have been drawn for one day. No sunlight whatsoever has entered the room that entire day.
Room #2: All curtains/blinds/shades have been kept open the entire time. However, the blackout curtains/blinds/shades have now been drawn, at the end of the day.
A scientist enters each now-darkened room. Can the scientist accurately detect or measure which room was the “sunnier” room during that day?
Putting aside long-term sun bleaching, which I understand can lighten fabrics when they are exposed to sunlight over a long period of time, my question is whether the photons of sunlight from a single day could be detectable, objectively, at the end of that day. Does sunlight “change” anything that can be measured, after the light is gone?
In: Physics
Yes.
Some of the photons were absorbed by the things in the room. Those absorbed photons have raised the temperature of the things they interacted with, so the warmer room is the one that you filled with sunlight for a while.
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