Light Cones

Abstract

Instructions: Consider a compact patch of 1+1-dimensional de Sitter spacetime lying between t = 0 and t = T > 0, and any two points (t, θ) and (t′, θ′) in this patch, where (t, θ) and (t′, θ′) are the time and space coordinates of the points in the standard spherical foliation of de Sitter spacetime. Please calculate the area of the intersection of the light cones of the two points within the patch.