Cosmological distances…
Some excitement was caused recently by the announcement of an E-type exoplanet, Proxima b, a planet orbiting the red dwarf Proxima Centauri in the Alpha Centauri triple-star system (Alpha A is a G-type star like the sun, while B is a K-type star, but both are much brighter than Proxima). That system is about 4.3 light-years from Earth, or 40.14 trillion kilometers. (Conversion lesson: convert to statute miles.) The size of the Milky Way is about 100, 000 light-years, so Proxima is right around the corner. Right? Wrong! Even distances in our galaxy are “huuuuge,” to borrow a word abused by two recent presidential candidates and the SNL comics.
More excitement was caused by the report from scientists at the RATAN-600 radio telescope at Zelenchukskaya in Russia. They detected a strong signal apparently originating in the direction of the G-type star HD 1611595, known to have one warm Neptune-like planet (40-day orbit). This star is 94 light-years away. The Russian report to the SETI committee was made without many details. The star might have rocky E-type planets too, so many UFO-ET enthusiasts and sci-fi addicts are in a frenzy, spurred on by the meaning of the acronym—“Search for Extra-Terrestrial Intelligence.” While some other Russian scientists wrote the whole thing off as terrestrial interference (covering their butts?), the scientific jury is still out (comments updating this are welcome). 95 light-years is many times 4, of course, but still small in comparison relative to galactic distance markers—4 is a walk to your neighborhood convenience store; 95 is a short car ride to the nearby Dunkin’ Donuts.
Let’s counter some knee-jerk reactions to these reports first. Coincidentally, SETI has a new focus on red dwarf stars. They can live billions of years longer than G-type stars, where SETI’s emphasis has traditionally been, because we know at least one G-type star, ours, has an intelligent civilization (although “intelligent” might be a questionable word to use sometimes). That extra stellar lifespan might allow a red dwarf like Proxima Centauri to be home to an ancient civilization far advanced beyond ours (and actually be intelligent?). The hurdles are enormous, though, for any kind of life in such a system, because livable E-type planets would have to orbit the parent star so closely that they would be tidally locked, one face always turned toward the star. That means life as we know it could only exist in that transition zone between eternal day and eternal night.
The second report is a bit more difficult to put down in this way: an E-type planet could exist farther out from HD 1611595 and have life. Without knowing the details of the signal (I only know it’s strong), one can’t use it to mark the source as being intelligent. If it were narrowband, seemingly coded, and beamed directly at us (how could they know to do that when radio had just been invented on Earth 90 years ago?), you might have something. But consider this: one scientist estimates that ten-to-the-thirtieth (one followed by thirty zeroes) watts would be needed to broadcast this signal if omnidirectional (i.e. not specifically aimed at us), and ten-to-the-fifteenth watts if beamed directly. The first corresponds to a Kardashev Type II civilization, one that harnesses all energy emitted by its sun (Dyson sphere?—that’s physicist Freeman Dyson, not my author-friend Scott Dyson); the second to Type I, a civilization that “only” harnesses all the energy falling on its planet.
Astrophysics, sci-fi, UFO, and ET enthusiasts aside, let’s suppose that we “discover” a civilization within tens of light-years from Earth, i.e. just down our “cosmic block”? Barring hitching a ride on some UFO, can we travel there to say hi? Not easily. It’s not even easy to have a long-distance telephone call. Conversations with planets around Proxima Centauri or HD1611595 would have turn-around times of years. If you think of all that happened just in the 20th century on our planet, you can imagine that changes on either planet might cause the ETs or us to lose interest. This pessimistic viewpoint assumes current science and technology, though (and ETs with a short attention span, I suppose).
Sci-fi writers (I’m one of them, of course) either have to live with these great distances and talk about the human generations needed to get to the nearest stars or invent some sort of FTL (faster-than-light) travel. Brian Aldiss’s 1958 Starship (also titled Non-Stop), a bit of portable dystopia, if you will, talked about the former, and is where I first encountered that generations-concept (I refuse to say whether I read it in 1958). An alternative to that is to use cryosleep or frozen sperm and ova (I used both in the last part of Survivors of the Chaos; Hogan used only the last in Voyage into Yesteryear, having robots take care of everything at the destination, including rearing the star children—Asimov would be proud).
It’s hard to create any kind of stellar commerce or political institutions without FTL, though. Some early sci-fi writers (from space-opera master E. E “Doc” Smith to hard sci-fi writers like Isaac Asimov, for example) just waved their hands at the problem, while others have come up with some scientific-sounding justifications for it. Hollywood movies generally just sweep the physics problem under the rug too. (In Sing a Samba Galactica, I spruced up the techno-babble a wee bit, essentially making Asimov’s “jump” a bit more palatable by using the multiverse concept. As a sci-fi writer, you come up with a good-sounding solution and get on with the plot.) Some ETs are tricky too because we tend to anthropomorphize any motivations they might have for stellar empires, which often just gives them FTL-abilities for conquest (I’m guilty of that in Sing a Samba Galactica, but that novel contains good ETs too, as well as hard-to-comprehend ones like Swarm, a compound intelligence spanning several civilizations in a galactic cluster—FTL-thought is required to maintain the integrity of that “creature”).
Moving human beings and life-sustaining materials cosmic distances might not be possible, but what about FTL communications? Come Dance a Cumbia…with Stars in Your Hand! points out one possible limitation of even a loose stellar confederation in a small galactic neighborhood stitched together via FTL transports. Without communications that travel faster than the starships, the latter are the speediest way to disseminate information, a situation similar to the days of sailing ships plying the waters of Earth. Orson Scott Card, Ursula Le Guinn, and others solved this problem by considering the “ansible”—a peculiar Harry Potter-like magical term describing an FTL communication device. In my universe of the “Chaos Chronicles Trilogy,” that communication problem remains at the end, leading inevitably to colonies going their own way sometimes (see Rogue Planet).
There’s no doubt about it: cosmic distances are tremendous, and Einstein’s upper limit, the velocity of light, is a real downer. Human beings might have to wait awhile, maybe forever, to explore even the near-Earth neighborhood of our home galaxy. We’ll have to wait even to say hi to ETs “out there.” If that bothers you, you can always explore via sci-fi, where authors imagine what exists in the immense cosmos. Or, even in our own solar system—cosmic adventures experienced from your armchair.
In libris libertas!
