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I don't believe the graphic is representing a boundary. I think it's representing the relative expansion of space over time. The observable universe does have
by fluoridation 3y ago
I don't believe the graphic is representing a boundary. I think it's representing the relative expansion of space over time.
The observable universe does have an event horizon that can't be reached due to the finiteness of the speed of light, though.
- fnordpiglet 3y agoI think the key point is the event horizon, or effective boundary, is relative to the observer. From the earth there’s a point beyond which we can never observe, even if we left today at the speed of light. However for a planet at that point everything looks “the same” to them - except the earth is at their boundary. The boundaries here aren’t absolute - they’re only relative to the observer.