The cosmic horizon is changing. Hooper has worked out how this will affect our neighborhood in the universe, which astronomers call the Local Group. This is the set of about 50 nearby galaxies that are gravitationally bound to the Milky Way and on course to collide sometime within the next trillion years to form a single supergalaxy. Consequently, the Local Group will be humanity’s home for the foreseeable future. Over billions of years, we might even colonize it, hopping from one star system to another and exploiting each sun’s energy along the way.
However, the accelerating expansion of the universe is sending galaxies over the horizon at a rate that is increasing. “As a result, over the next approximately 100 billion years, all stars residing beyond the Local Group will fall beyond the cosmic horizon and become not only unobservable, but entirely inaccessible,” says Hooper.
That’s a problem for an advanced civilization because it limits the number of new stars that are available to exploit. So the question that Hooper investigates is whether there is anything an advanced civilization can do to mitigate the effects of this accelerating expansion.
I have to say, this concern is high on my list also: the possibility of running out of stars for human beings to exploit.
More seriously, I am bemused by this line of thinking. Billions of humans live in poverty, are daily endangered by hunger or disease or war; we lack a cure for cancer — we lack a cure for the common cold — we lack a cure for male pattern baldness —; and yet there are people worrying that we will eventually have no more stars to plunder to satisfy our energy demands.
Well, enough of this. Time for me to get back to planning the first year of my reign as God-Emperor of Terra. Because it could happen, you know, and I’d rather not be caught unprepared.