Wednesday, 15 July 2015

the sun - When we see the Sun, do we actually see its past?

The speed of light in a vacuum is 299,792,458 meters per second, not infinite. Let's say, for example, particle of a beam of light, the photon, is emitted. It takes ~8 minutes to get to us; when it hits our eyes, we see it. This means that we see a photon that was emitted from the sun 8 minutes ago. We aren't, per se, looking "back in time", but we're looking at a photon that is ~8 minutes old.

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