Most of the scientists I know like science fiction. Some of them actually write science fiction. I grew up with the genre and consider myself a serious science fiction fan. For some of my artistic life I have been a science fiction professional as well. So I am pretty much familiar with just about any science fiction scenario, including those that involve violations of the laws of physics, unreal universes, impossible powers, and extrapolations from esoteric physics that are part of the current theoretical repertoire. I have also made up science fiction worlds and stories, though I haven't tried to get anything published; it's just private entertainment for me and a few friends. But since I know I have some high-powered scientist fans out there reading this, I want to offer up this set of s.f. questions which I have been pondering for many years. Here goes.

Let's imagine that in the distant future some form of star-drive that evades the speed limit of light has been discovered, and that humanity, or humanoids, as well as some non-humanoid alien races, have colonized a section of the Galaxy, perhaps a quarter of its circumference. They live in the "habitable ring" around the center, not too far from it and not too close to the dangerous radiation and crowding in the core area. They inhabit thousands of solar systems, but their range is limited. They cannot reach the other parts of the galaxy without going a very long, difficult distance around the core. So they are basically confined to one area of the galaxy.

Then someone discovers, or re-discovers, a way to reach all the way across the galaxy in one big jump. It's sort of like TV's "Stargate" or one of Babylon 5's "jumpgates," but instead of going a "short" distance of a few light-years, it is a Great Gate that bridges almost the entire 100,000 light year diameter of our galaxy. A group of colonists pass through this Gate, to a suitable world on the other side of the Galaxy. And then the Great Gate closes. The unusual astronomical circumstances which allowed the Great Gate have ceased, and may not be repeated for hundreds, perhaps thousands of years. So the colonists on the new planet are cut off from their origin and must start their own civilization with what they have brought and what they can create from their planet's resources. They have not, for various reasons, preserved the advanced technological knowledge of their previous home, so they do not have any manned spacecraft or communications that can go beyond the solar system, let alone faster-than-light. Their level of technology is roughly equivalent to our current era, plus a few decades perhaps.

Now here are the questions. Our colonists know that they came from an interstellar civilization on the other side of the Galaxy. Is there any way that they could detect it from their new planet? The core of the Galaxy is in between the new settlers and the old civilization, which remains in the plane of the galactic disc. And then, if the old civilization is now 100,000 light years away, could any of their transmissions have even reached the new colony? Has the "parent" civilization had advanced technology long enough for its electronic signals to traverse the Galaxy, before our colonists set forth? From the frame of reference of the new colonists, does the old civilization still exist?

If a science fiction scenario admits faster-than-light, or wormhole, or teleportation travel, then space-time as relativity knows it, is violated. Star Trek's "Enterprise" and its successors dashed about the Galaxy and somehow managed to keep in time synchronization with not only the home planet but all the other ones they visited. If it was February 2307 on Earth, it was also February 2307 on the Enterprise, as well as on Deep Space Nine. I have long pondered how this synchronization could be maintained. My idea was that the interstellar network connected by "sub-space" communications and faster-than-light travel would produce what I call a "temporal island" where an artificial synchrony of time was maintained. As soon as that communication was broken, however, for a sufficiently long enough period, then the "natural" fabric of space-time would reassert itself, and the distant planet would no longer be tied to February 2307.

Now suppose that our new colonists, having re-developed their technology or re-discovered a way to make a Great Gate, get curious and want to go back and visit their old home. What will they find? Has the old world been progressing at the same rate as it has when they left it behind? Has it simply been existing in a parallel, but unreachable, "temporal island" which can then be re-connected to the colonists' time? Or does the re-attached Great Gate drop the returnees into another era entirely, nowhere near the time that they left?

This is where imagination goes where physics cannot. The old "Star Wars" introduction phrase, "Long, long ago, in a galaxy far, far away…" implies something that can only be imagined and never really detected. The galaxies that cosmologists now view with the Hubble and other space telescopes are seen as they were when the light that we now see left them. Astronomers are seeing light that is billions of years old. But those galaxies may still be "out there," going through time that may or may not go at the same speed that ours does (?). The galaxy we see as a chaotic inheritor of the early universe may "now" be an orderly place inhabited by advanced people who wear great-looking fashions. But a temporal synchronization that violates spacetime cannot exist, or can it? Thus we will never be able to really know what is going on in those galaxies "now," because there is no one "now" for the universe. Only our imagination can take us through the Great Gate.

Posted at 3:24 am | link