What is time? - Neil deGrasse Tyson

one of the famous quotes is time is defined to make motion look simple okay because you cannot describe motion without some reference to time and so you define it so that motion is something we can describe easily with equations and then so that's kind of a cop-out answer but it's a very functional answer for the physicist I also think of time as this prison time makes us all a prisoner of the present forever transitioning from our own past into an unknown future and that's particularly disturbing to me because we can move back and forth in any other coordinate you know up and down left and right forward and back Oh stuck in time we can't move forward or backwards in time arbitrarily so that coordinate has a kind of a fundamental difference from the other three now my my professional ancestors the earliest astronomers basically invented timekeeping all right so all measures of time historically would derive from cosmic rhythms so what we today we would say the rotation of the earth but in the day it was the movement of the Sun yeah so that gave you a day and then the sun's position on the sky throughout the day is differed and temperatures change so that gave us the seasons and then of course back then it was the Sun doing all this but we would learn that we rotate and we revolve around the Sun so that took really long to figure out disturbingly long I mean only like 400 years ago when so what it tells you is that you can keep track of time even though you have no frickin idea what's going on because all that matters to you is that things repeat if you have something that repeats predictably you then you have created a timekeeping mechanism Oh

Channel: UNSW Science

Views: 202,959

Keywords: Neil DeGrasse Tyson (Organization Leader), Dom Kountouris, Time (Dimension), Theory Of Relativity (Literature Subject), Physics (Field Of Study)

Id: LIPOR55M_P0

Length: 2min 29sec (149 seconds)

Published: Tue Aug 25 2015