I am amazed at how many of the practical implications of a correct understanding of the universe and the implications of the Theory of Relativity are completely lost on most science fiction authors. Either that or most authors are so concerned with the wrong headed idea that space travel and intergalactic communication are necessary that they gloss over the simple facts of physics.
Time travel to the future is a practical reality. I've read debates between characters in science fiction books about the effect of the constant acceleration of a gravity well like the earth on stationary objects on it's surface that seemed to be inconclusive. Well physics defines time as relative and gravity wells as warped space time so guess what living on the Earth's surface is flinging us into the future by the very fact that a gravity well slows down time. The reach and power of the Earth's warp on space and time is revealed in the orbit of the moon. The moon is traveling in a straight line. Space time is so warped by the density of matter at the center of the Earth that space time around the Earth is curved right around into a sphere! The Earth is flat! It's a space time plane warped into a sphere.
The effect is very dramatic when you consider the fact that one second on the surface of the Sun is equivalent to one year on Earth. Just think of the implications that the Mars Rovers have lasted not just a lot longer than they were designed to last but that they are also on a smaller planet with a smaller space time warp with a smaller slowing of time. Meaning that even more time has passed for the rovers on Mars than for us on Earth. Or you consider that voyager 1 has been travelling for over a decade without the benefit of any space time warp to slow down the passage of time for it except for the Sun. It would be interesting to calculate an estimate of the real length of voyager 1's journey as experienced by voyager 1 and then translated back into Earth years.
I'm only halfway through the book and am heartened to read facts about our Universe that support my theory that space travel by humans is a waste of energy. Any intelligent entity with a basic understanding of physics will know that in order to know anything about the Universe you only need to look inward to the quantum for understanding and outward to the universe for information.
Makes me wonder why the author encourages space travel and colonization. When it seems that sustainability and peaceful coexistence is a more reasonable approach to avoiding extinction. I know there are extinction level events that will require preparation through technological advancement in order to avoid catastrophe. Like supervolcanoes, super tsunamis, and ice ages. But in my opinion a more concerted effort with global cooperation is required. Instead of waiting for Ragnarok or Judgement Day and trying to start the whole process over again on another planet.