EDWARD'S LECTURE NOTES:
More notes at http://tanguay.info/learntracker
C O U R S E 
Understanding Einstein: The Special Theory of Relativity
Larry Lagerstrom, Stanford University
https://www.coursera.org/course/einstein
C O U R S E   L E C T U R E 
Events, Clocks, and Observers
Notes taken on June 25, 2015 by Edward Tanguay
concepts that are fundamental to the special theory of relativity
events, clocks, and observers
this concept is almost trivial in a sense
part of Einstein's genius was to look at these concepts that many people took for granted
what does it mean to observe something?
where something happened
when something happened
e.g. a flash occurring at a specific place and time
three dimensional coordinate system
x, y, z axis
any given event would have an x,y,z coordinate
measuring system
an event happens at x,y,z
but we need a time as well
so we need a system of time keeping
so time is the fourth dimension
not really as profound as it seems to be
three spacial coordinates and time as well
we assume we have an origin, e.g. (0,0,0,0)
we say this is the observer at time 0
gets to the question how we measure time
there is a problem with that, which is that time does not move at infinite speed, but a finite speed
light from the flash takes a while to get to the origin where the observer is
you could figure out how far away the light is by how long it took to get to the observer
we could also put clocks at all points
the "photo clock principle"
every single point in time has a clock associated with it
we'll assume when the flash goes off, there is a photo taken recording the x/y/z/t coordinates
a lattice of clocks
a grid of clocks
issue: there is an infinite number of points
resolution: depending on the accuracy we want, we add or subtract the number of clocks