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I understand that an event, in a four dimensional space-time, produces a light cone. As time increases the cones gets larger on either side of the event (past and future). For example the if the sun where to "go out" it would take 8 minuets for the earth to be affected by it simply because it takes approximately 8 minuets for light from the sun to reach the earth due to its location in the future light cone of the event (the sun being the event).

Einstein made a suggestion that space-time is warped (vs flat) by the distribution of mass and energy and that bodies (like earth, jupiter, etc.) are meant to follow straight paths but cannot in a warped space (or appear not to because space is warped). However light supposedly follows these warped paths (called geodesics) as well even tho light is energy.

How can space bend light? and why does light have to follow a specific path which is warped by space? Things with mass (like water) have to go around things (like rocks), but light can go through certain things or expand, but it doesn't move to the side like water does to a rock. Does it?

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up vote 2 down vote accepted

The underlying space is curved. There is no 'straight' path. It's like asking why planes have to travel on great arcs to get the shortest path between cities on the Earth's surface, rather than flying on a straight line on a Mercator projection.

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but the earth is round... space is infinite (theoretically) – luca590 May 25 '11 at 4:32
so what? and if that is the argument, space is round too near big masses, that roundness is the curvature – lurscher May 25 '11 at 4:35
but than where does that path "empty into" if it is bent what happens when it gets around the mass because it cant just fill up the universe. What path does it have to follow after that. plus in an infinite space you should be able to go in a straight line. in fact because thats the shortest distance that's what energy does – luca590 May 25 '11 at 4:38
@Luca: yes, but there's more to the curvature of the Earth than the fact that if you go around, you'll come back again--the curvature of the Earth also changes what you mean by a 'straight line'--a non-curving line no longer gives you the shortest distance between two points. It turns out that general relativity predicts that such a fact also turns out to be true for ay situation where gravity is present. – Jerry Schirmer May 25 '11 at 4:39
@lurscher: yes, that's my point. Curvature alters the shortest distance paths for everything, even light. There's no spooky contradiction. – Jerry Schirmer May 25 '11 at 4:43

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