I watched an interview with Neil deGrasse Tyson on The Late Show with Stephen Colbert where he briefly mentioned a disturbing thought. It is something that I have never thought of before, and the idea borders on the eerie.
The idea is this (and here comes a mouthful): If all our knowledge of the Universe is based on observations of distant galaxies (and Milkyway stars), and we accept that the Universe is expanding at such an accelerating rate that at some point in the future only our nearest stars will be visible to whoever inhabits Earth, and that then those future inhabitants will need to explain the Universe based only on what they can observe, then it is possible that we are today trying to explain the Universe based on largely incomplete data.
Like, imagine that there is much more stuff out there, stuff that could help us explain some of the scientific "mysteries" such as dark energy/matter, but it is beyond our horizon. We don't know what is missing from our view.
And so I guess the question is this: How does this affect the validity of our current models of the Universe?