|April 26, 2013|
In a previous article -- Is anybody out there? I discussed the Fermi paradox, and using my best guesses and back of the envelope calculatons, suggested it would take no longer than 100 million years for us to colonize the disk of our galaxy. Herein I offer more musings about our ultimate endeavor.
But first, let's address the question of whether there is other intelligent life in the universe. To answer that in relation to the Fermi paradox, we should realize that the Fermi paradox only applies only to our galaxy. We assumed 10 light year hops between stars. There is a gulf of millions of light years between galaxies. It is likely impossible, no matter how advanced a civilization, to engage in galaxy hopping. But is there life out there beyond out galaxy? Let's look at one of my pictures of the horsehead nebula:
Here's just the horse head from the Hubble telescope:
Here's a close-up of the top left corner: Each of those fuzzy spots is a galaxy with hundreds of billions or even trillions of stars. It's that way everywhere you look! (Isn't Hubble amazing). There are at least 175 billion galaxies in the universe and perhaps as many as a trillion!! There can't be any doubt that there is intelligent life somewhere in the universe.
Now back to our galactic conquest of the Milky Way. If we set out in both directions around the galaxy at once, then we will meet ourselves 100 million years or so later, on the other side. In that time Earth will have traveled nearly half way around the galaxy. Just before we close the net, communication between the two frontiers, at the speed of light, will likely take place between a vast network of relays. The outer circumfrence of the galaxy is about pi times 100,000 light years. So it will take over 300,000 years for the right hand to discover what the left hand is doing.
During the 100 million years of conquest, if there were no genetic engineering interference, the two groups that finally meet on the other side of the galaxy would have divergent evolutions of 200 million years. 200 million years ago, mammals had yet to evolve and even the dinosaurs were just getting started. Thus when we meet ourselves on the other side of the galaxy, we would be meeting aliens! There would be no reason to believe the two groups would resemble each other in the slightest. Since communication would take 300,000 years and because we will have long mastered genetic engineering, we shouldn't expect adequate forwarning about our fellow humans' appearances. Certainly 300,000 years of genetic engineering could accomplish as much as 200 million years of natural evolution! So even if there isn't anybody else out there (in our galaxy), one day earthlings will encounter aliens -- earthling aliens.
And one final note on the possibility of galaxy hopping. It will one day be possible to visit the Andromeda galaxy even though it is now 2.5 million light years away because in about 4.5 billion years the Milky Way and Adromeda are set to collide and merge.