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questions
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Spacetime Diagram for Robertson-Walker Universe
For the Robertson Walker universe with metric
$$ds^2 = -dt^2 +a(t)[dx^2+dy^2+dz^2]$$
where $a(t)=t^q$ and $0<q<1$, the light cones in the spacetime diagram are drawn as follow:
From the diagram, ...
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3
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Does our past light-cone have some extension in three-dimensional space?
On spacetime diagrams cosmologists represent our past light-cone as a two-dimensional surface extending back in time, on which are situated all light-emitting events which we can observe today. This ...
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Why can't we look at the future with telescopes? [closed]
I understand that space-time in non-linear. How come, though, all the light captured by telescopes allows us to see only the past in all directions but not the future? Does that mean that there are no ...
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What is the meaning of the particle horizon in conformal diagrams?
I'm reading "Physical Foundations of Cosmology" (Mukhanov) and in Chapter 2.3 conformal diagrams get introduced. They seem to be a (graphical) tool to understand the causal structure of the universe. ...
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