If you imagine the map that you see

[music] on a airplane, imagine you are

flying from San Francisco to

>> [music]

>> London. Here is Greenland and here is

England. Obviously, the plane should be

flying

like this, moving along the shortest

distance [music] from one place to

another, but instead they take this

massive detour that clips Greenland and

heads on [music] down. You know that in

fact that's not what's going on. You

know that in fact, despite what it looks

like on the graph, this is not a

straight line. This this rum line

sometimes called is not straight

>> [music]

>> and would certainly not be the shortest

path. And this is in fact, to good

approximation, a straight line, as I

will now demonstrate.

And you can see that the straight line

would go over Greenland

and hit London. That's obvious on this

map cuz this map obviously reflects the

curvature of the earth. This map is

getting confused and it's getting

confused because it's trying to pretend

that the earth is flat. And whenever you

try and take something that is curved

and pretend it's not curved, you will

inevitably be end up being wrong about

[music] what is and is not a straight

line. And just like in general

relativity, the reason you are confused

about what's straight and what's not

straight is that you are trying to

pretend with this graph that you are in

a flat space-time and in fact [music]

you are in a curved space-time.