I've seen a few articles like this that say the majority of the universe is practically unreachable to us, even if we were to travel at the speed of light. My understanding is that there is enough energy and matter in between us and bodies that are ~14-15 billion light years away that the bodies are moving away from us faster than the speed of light. Because we are limited by the speed of light, those bodies are now unreachable to us. Is this roughly right?
I am trying to build a mental model of what this would look like and came up with this:
Hopefully, I am not oversimplifying too much, but I imagine
Dbeing the body we want to reach
Cbeing representations of the "matter" that are causing space to expand.
- None of these are individually stronger than a black hole
- The distances
CDare not expanding faster than the speed of light,
- but the combination of them makes
ADexpand faster than the speed of light, thus rendering
That being said, if we were to shoot a photon from
A, would that photon not eventually be able to reach
B in a finite time? And if it can reach
B, then it should eventually
C? And if it can reach
C, then it can reach
D actually reachable?
More specifically, any point in the universe would be reachable as long as no segment of our path to that point expands faster than the speed at which we're traveling.
So probably something is wrong with my mental model or my interpretation of the article, but I'm not sure what - can someone help me understand?