from Hacker News

Clock time contra lived time: Bergson vs. Einstein

by danielam on 10/1/24, 8:20 PM with 1 comments

• by taylodl on 10/2/24, 1:28 PM

  Maybe this was an issue for those born and raised in the 19th century and then being hit with the "absurdity" of relativity, but for those of us born and raised several decades later, it's a moot point. We all understand that your experience of duration can be measured by your local clock that strapped around your wrist. Everything appears normal to every observer in their own reference frame, it's only when looking at other people in other reference frames that things appear "off."

  One interesting aspect of this is determining the age of the universe. Every point of the universe is literally in its own world line and would therefore measure a different time to the point of the so-called "Big Bang." To measure the "true" age of the universe cosmologists employ cosmic time: https://en.wikipedia.org/wiki/Cosmic_time

  This topic also arises at the event horizon of a black hole. To the unfortunate person falling into the black hole, the passage of time seems normal. To observers outside the black hole, the person never even reaches event horizon as that world line extends to infinite time. To the person falling inside the black hole it would appear the universe is ending, and in some measure, that is correct.