←back to thread

171 points belter | 1 comments | | HN request time: 0.198s | source
Show context
nyc111 ◴[] No.41870842[source]
I would really appreciate if people writing these types of articles first give rigorous and unique definitions of space and time.
replies(4): >>41871770 #>>41892831 #>>41892968 #>>41893041 #
ziofill ◴[] No.41892968[source]
My favourite explanation (which IIRC is in a book by Brian Greene) is that you can think that everything always moves at the speed of light in a 4D spacetime. That way, if you stand still, you're moving only along time, and as you tilt your velocity vector more and more toward the space dimensions you have to travel more slowly along the time dimension. At the limit you are moving at the speed of light along some space axis and technically your time is "frozen".
replies(4): >>41893042 #>>41893361 #>>41893463 #>>41898059 #
1. creata ◴[] No.41898059[source]
Some of the answers at https://physics.stackexchange.com/q/33840 explain why "everything always moves at the speed of light in a 4D spacetime" is a statement that, at best, has no content.