Where does our arrow of time come from?
Ethan Siegel

I thought this morning, you said in an earlier post that a photon takes 8 minutes to travel from the sun to the earth. But that photon doesn’t experience time. If I reflected that photon back to its origin, I suppose it would take another 8 minutes to reach the sun. And that photon still hasn’t experienced time passing. Although its origin has experienced 16 minutes of time passing.

Did the photon travel in time into the future of its origin?

If you and I parted ways and I could make you travel at the speed of light, if we re-met, wouldn’t I have traveled into your future?

Show your support

Clapping shows how much you appreciated Michael Kelly’s story.