Posts Tagged galaxy
The title of this post isn’t meant to ask where you are in a spatial location, but in terms of time. Where are you—where are we all, for that matter—in the life of this universe? I’ve been thinking about this for a long time. We all live on a rather attractive blue, white, green and brown planet circling a rather ordinary yellow-white star in a rather ordinary galaxy somewhere in the middle of billions of other galaxies which together constitute what we affectionately refer to as the “universe.” This universe arose from a massive expansion of all matter and energy some thirteen billion years ago, and is rapidly expanding and expanding, apparently to go on forever, driven apart by wild forces within itself. It will go on for time immemorial, never to return to its original state. That’s, at least, the current thinking.
Here we are, sophisticated, sentient human beings, watching this all unfold, trying to make sense of it. I’ve wondered, ever since I heard of the “big bang” hypothesis, which is the current favorite explanation of how we got here, if there isn’t an alternative explanation, that the universe will eventually run out of steam and collapse back onto itself in a sort of “big crunch,” or “big splat,” from which it would rebound into another expansion and another universe, and so on, ad infinitum. That seems to me to be a more logical way for the universe to run than just one “bang” which blows up like a balloon and dissipates out in the nether regions, never to be seen again. The “single bang” theory doesn’t explain what came before the expansion, nor what will come after it. But that may be the way it really is. Dark energy seems to be pushing the galaxies apart faster than dark matter can keep them together.
Philosophically, this is mind boggling. We are the only species on this planet that really understands, to any degree whatsoever, the goings-on out there in space. We’ve been watching the skies for thousands of years. We’ve sent satellites into orbit to observe it. We’ve sent men to the moon. Do you think that cat or dog or goldfish or parakeet in your house cares much about the big bang? Do the deer and the wolves in the forest understand that the little red dot in the sky is a cold, solid planet rather than a blazingly hot star? Or even what a star is in the first place? No, just us. Yet we humans make up such a miniscule percentage of the universe, it’s difficult to estimate how many zeros I’d have to put down to the right of a decimal point to give that percentage. We humans are what I might call “universe sentient.” We know where we are, though we can’t travel very far in it. We’ve seen the stars, the Milky Way, and some of the other galaxies that make up our universe. We have a lot to learn, granted. But we are capable of learning it. We have the mathematical skills and computer skills to master the intricacies of the universe. No dog or cat, or even chimpanzee, has that. Most likely, other civilizations exist in our galaxy with similar skills, perhaps even more advanced. (Maybe they can tell us if dark matter and dark energy really exist.) But philosophically we are alone, and, I suspect, will remain alone for the foreseeable future.
Could life ever arise on the planet Venus? That is, Venus as it exists today. Venus is a hellish place, with temperatures of around 462°C at the surface, rain composed of sulfuric acid, lava-flows over much of the surface, and an atmospheric pressure around 90 times that of Earth at sea level. It’s not a pleasant place, and a manned spacecraft would find it difficult to land there, and it might be even more difficult for humans to get out and walk around. In fact, I think we can dispense with the possibility of humans walking on Venus’s surface for the foreseeable future.
Many billions of years ago, some scientists speculate, Venus may have had a climate similar to Earth. Water may have been present in abundance, enough to fill relatively shallow oceans. An atmosphere of oxygen may have existed that could have been conducive to life. But if it did, under the influence of the heat from the sun (Venus gets about twice as much sunlight as Earth) the oceans boiled away, the water was split by ultraviolet light into hydrogen and oxygen, the hydrogen escaped into space, and the oxygen combined with carbon on the surface to form carbon dioxide, and the greenhouse effect took over. That pushed the temperature into the stratosphere. So to speak. And here we stand today.
But the presence of water making life possible on Venus in the distant past isn’t what I want to hypothesize in this post. I’m thinking about the possibility of life on Venus as it exists now. Yes, in the presence of all that heat, lava, pressure, and sulfuric acid. Earlier, on March 13, 2011, in a blog post entitled “Life–A New Definition,” I suggested that life on any arbitrary planet should be defined as “that which arises . . . under the influence of the energy from its sun over and above any other milieu . . . .” That’s without regard as to what the life forms look like, or what they’re composed of, or how they replicate, or any other limiting factor we may require to define life on Earth. We can’t think of life on other planets within the limited range we find here on Earth.
So, what would life on Venus look like now? Under the influence of that tremendous heat and pressure, chemical reactions are running wild, at least in comparison with Earth. That might be a good thing. It might be the very factor that makes “life” viable on the surface. Lava may stay liquid all the time on Venus. Possibly a life form could arise composed of lava globules that slowly creep across the surface, consuming other bits of the ground, extracting necessary elements, metabolizing them by sulfuric acid digestion, and eventually dividing into smaller globules that continue the process. And that’s just one scenario. I’m sure others could be visualized by those who are better at chemistry than I, so there’s no sense in me speculating much further here.
I certainly realize that the chance of “life” actually existing on the surface of Venus is probably very low, and that speculating about what it looks like could be a somewhat unscientific pursuit. But the real reason for looking at Venus this way (sorry about that) is that it gives us a different way of looking at life in general all across the galaxy. (Think what it would mean if we did find some sort of life on Venus.) Life certainly exists on (a few? many?) other planets somewhere in our galaxy because there are so many of them, and we should always be aware that it won’t necessarily look like us. It may be so vastly different that we may not recognize it at first, and we have to remain open to any possible physical form, and any possible metabolic form. Temperature and pressure won’t necessarily be a limiting factor.
Last week I posted a segment on the lack of imagination in science fiction today, with a view toward how so many sci-fi characters are humanoid in appearance. Now I want to take a short look at what I’m talking about when I say “humanoid.”
In the evolution of animals over the past two billion years or so, there’s been a tendency for the sensory organs to become concentrated in the head. This is true for all the higher animals—and by that I mean basically those with a backbone and a large nerve cord running down the back—but it’s also true for some lower animals, such as insects and other arthropods. This is called cephalization, and it’s what is so often copied by us sci-fi writers when we devise characters to populate planets far, far away. This process has put four of the five traditional senses in the head: sight, hearing, smell, and taste. (The sense of feel, of course, is present throughout the body, we don’t have just one organ for that.) Why this should have happened evolutionarily, I’m not sure, but it may have to do with keeping the nerve fibers that run from the sense organs to the brain as short as possible. That may, in turn, have been to allow the information collected by those organs to be processed as rapidly as possible. If our eyes were in our kneecaps, for example, the nerve fibers would have to run all the way up the body to the head. Might be some loss of information in that long a trip. Secondarily, in a long, slender animal, such as a fish or a cougar, having the sensory organs up front could allow the animal to detect things ahead—food, danger, a mate, whatever—as immediately as possible, and shorten the reaction time to whatever’s out there. Always a good idea.
But for whatever reason, this is how humans are constructed. And so are many of the characters in science fiction. The Roswell “little green men” are shown this way, and this is the most likely reason they’re not real. Any time I see a purported visitor from outer space that looks like it’s been based on humanoid features, including most prominently the cephalization of sensory organs, but also including two arms and two legs and a large brain case, I know it’s almost certainly a fake. There’s no reason I can think of to believe that life—and I’m including intelligent life here—on other planets or worlds will be based on that principle.
Having said that, of course, I can’t rule it out either. Of all the trillions and even quadrillions of planets that must exist in all the galaxies in our universe, could there be a planet or two where evolution has taken the road to cephalization? To put it more simply, are there beings that actually look like us? Definitely possible. But considering the variations of conditions that exist on the planets we’ve detected so far in our galaxy, (and that’s an extremely tiny proportion of the total) it’s much more likely that life will be quite a bit different in appearance than anything on Earth. We may not even recognize it.
Enrico Fermi is credited with asking the question that forms the basis for “Fermi’s Paradox.” That is, where are all the aliens? Why haven’t we been visited here by aliens from another planet? There are so many stars in our galaxy, and many of those stars, even perhaps all of them, have planets orbiting around them. Surely some of those planets must have life existing on them that has developed the capability of traveling the galaxy and visiting other stars and planets. With hundreds of billions of stars and maybe ten times that in planets, where are they? Why haven’t we seen them? Why hasn’t someone landed and said, “Take me to your leader?”
I’ve seen articles recently that attempt to answer the question by postulating several hypotheses. One of the most common is, “It’s too far—they can’t get here.” That hypothesis usually falls to the argument that a sufficiently advanced civilization should be able to build and send out a ship large enough to allow space explorers to live out their lifespans and spawn ancestors as the ship sails through space. A sort of “Genesis Ship.” Any visitors to our planet could be descendants of the original spacefarers. That would take an immensely large ship, but who’s to say it couldn’t be done?
That hypothesis also falls to the argument that perhaps an advanced civilization has learned how to open a wormhole, or failing that, to use an already existing one, and travel from one section of the galaxy to another with just a short hop. Who’s to say that couldn’t be done?
Generally, we tend to argue ourselves out of almost any supposed block to long distance space travel. It can be done, we confidently assert. And, we continue, here’s how. And we launch into detailed explanations of how they could get here. So, where are they?
Let me throw out a different possibility: perhaps we have been visited here. Maybe they’ve come in droves, and they’re all around us. Maybe they came many thousands of years ago and left, muttering something to themselves about nothing here worth visiting. Perhaps they set out space buoys to warn other travelers away. “Don’t go to that blue planet. It’s worthless.” After all, we still do see UFO’s in the sky. Not all UFO’s have been identified. Some are balloons, some are government projects, some are airplanes, some are blimps, and so on, but what about the ones we can’t identify? It seems logical to me that if aliens were to visit us here, they’d want to keep their presence quiet. For whatever reason. How can you read the mind of an alien if you don’t even know whether it exists in the first place?
Any alien capable of traveling the galaxy, or through a wormhole, might also have developed the capability of masking his presence to the point that we don’t even know he’s here. In that sense, the Romulan cloaking device of Star Trek might not be so farfetched.
Here’s looking at you.