The most amazing thing about the world that I can think of, is that the only reason we even understand that our universe had a beginning, or that there are other galaxies besides our own, is because we happen to have evolved just in time to still be able see the rest of the universe retreating from us in all directions. Looking out into deep space is literally looking into a time machine. Many of the galaxies we see today are so far away, so many billions of light years away, that they may not even exist anymore. In other words, by the time the light from those galaxies reach us, most of the stars within it have probably already died. Those far-off ancient galaxies may have merged into different superclusters by now or been swallowed up by a super massive black hole, but we will never know. The most far off things we can see in the visible universe are steadily moving infinitely farther and farther away from us, and everything that surrounds them. If there is intelligent life in a trillion years that looks out at the cosmos, it’s only reasonable conclusion will be that it’s galaxy is the entire universe. The rest of the universe will have retreated so far away toward eternity by that time that it will be undetectable.