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'Hundreds of Worlds' in Milky Way
Raphael Emportu writes "BBC news is reporting
that rocky planets, possibly with conditions suitable for life, may be more common than previously thought in our galaxy, a study has found.
New evidence suggests more than half the Sun-like stars in the Milky Way could have similar planetary systems.
There may also be hundreds of undiscovered worlds in outer parts of our Solar System, astronomers believe.
Future studies of such worlds will radically alter our understanding of how planets are formed, they say."
Given hundreds of worlds within our own galaxy, if we apply the Drake Equation, there's a good chance that there's another intelligent species out there, although the chances of it being of a sufficient technological development to make its presence known is slim. Also, the 'accepted values' for the various parts of the Drake equation are subject to (sometimes intense) debate.
This being said, given that most of these "nearby" worlds are tens of thousands of light-years away, with the current state of our technology, we might as well be alone.
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~ |rip/\/\aster /\/\onkey
As long as the temperature of the liquid is sufficiently stable, there are sufficient chemical building blocks and there is not too much current, single cell organisms and then multi cell organisms could emerge..
Depends on how you define "intelligence". Our liquids are certainly teeming with intelligent life. Life itself apparently began in our oceans. Fish are certainly very smart - they feed themselves, find mates, defend territory, build defensive structures, some species live and travel in social groups, etc. These are all signs of "intelligence". Then if you want to cheat a bit and look at the ocean mammals - seals, porpoises, whales, these are extremely intelligent aquatic beings.
Arthur C. Clarke, however, argued that CIVILIZATION, however, could not evolve in an aquatic environment, for the simple reason that you cannot have fire underwater. His interesting theory claims that fire, and our control of fire - has been a driving force in our technology. First the fire we would use for slash and burn agriculture - which while being devastating for the environment over the long term gave many short term advantages to the primitive farmer. Fire to make steam is what drove the industrial revolution. And that same power is still in use today, though we get our "fire" in the form of Uranium, or by burning fossil fuels. Then there is the "fire" from the sky - electricity. Harnessing this particular "fire" would be pretty tricky underwater.
I guess it's an interesting concept to play with, and surely there are many possibilities that we biased, land dwelling humans could never dream of, but I respect Mr. Clarke and his idea. I think it would be difficult for an aquatic civilization to arise here or anywhere else.
Seven puppies were harmed during the making of this post.
There are plenty of volcanoes under the water here on Earth. Could those serve as a source of fire?
Perhaps primitive marine creatures would realize that some sort of algae-like food source grows better in the warmer waters around these "glowing liquid not-water" sources and start building walls around them to hold in that temperature. Sort of like farming - but with algae instead of regular "crops". This would give them a stable food source and they could get to thinking about other things.
Reading code is like reading the dictionary - you have to read half of it before you can go back and understand it.
The probability for intelligence seems to me to be the biggest hurdle. That humans are intelligent at all seems nothing more than a genetic fluke, and not a guaranteed outcome.
However, given our understanding for life, and how it evolved, it would seem that complex life forms would probably NOT be rare at all.
The biggest hurdles for human-like intelligence probably includes the following:
1. Self replicating molecules. I'm not sure how precise the conditions for getting life started are, but it probably isn't something we would see very often.
2. Conditions remaining stable for those molecules for a very long time.
3. Symbiotic relationships developing between organisms. (requirement for multi-cellular life)
4. The creativity mutation. (for lack of a better term.)
In between, it seems that the process of natural selection would be the driving factor, but those 4 items listed are probably the most important 'leaps'.
With regard to the creativity mutation: As I recall, there was a proto-human homonid that DID use tools, but never developed on that tool (The stone axe they used at the beginning of their existance was the same stone axe that they used at the end of their existance) And that period of time wasn't short, something on the order of millions of years where they used the exact stone axe. While they were using a tool, there was no real thought behind it. In that respect, it seems that it was much like a spider's web, a very precise tool for survival but instinct rather than a developed idea.
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The speed of light is a barrier like few the humanity has ever found.
Imagine if you would a cure to aging or a method to remain in stasis for hundreds or thousands of years. Once we get that out of the way, traveling to another solar system isn't that far fetched. It is suspect there is enough material in the vacuum of space between systems that could help refuel a fast traveling vessel to keep propulsion up and since there is no weather or space bacteria (that we know of) erosion and decay won't be much of a problem.
Now, granted ones who take such a trip will most likley never see their home planet again or those who they left behind so it will take a brave bunch to spend those long times in stasis or simply entertaining themselves with what ever VR or holodeck they have in the future.
I remember reading an article that if humans could at least travel close to the speed of light and sent ships from one planet to all the closest they could colonize and the repeat that the Galaxy could be colonized in about 1 million years. Now that seems a lot for us, but astronomically that is a drop in the bucket compared to the hundreds of millions of years it took nature to evolve intelligent life.
Now if people like Aubrey de Grey do acheive their goals of life extension then traveling thousands of years may not be that big of a deal for humans in the future.
"I am the king of the Romans, and am superior to rules of grammar!"
-Sigismund, Holy Roman Emperor (1368-1437)
From what I hear, our best chances of finding life in our solar system is Europa. It's a giant ice ball, but beneath a thin ice shelf, there's thought to be an ocean very similar to Earth's ocean in chemistry, that's about 100km deep. Other major possibilities include Mars and Venus, both of whom have environments we've already found can support some Earth-born forms of life. We suspect Mars may have supported multi-cellular life in the past, but Europa has the best chances of supporting it today.
If you believe everything you read, you'd better not read. - Japanese proverb
The question is whether we want to have any planets. From Earth, for example, you could construct 10000000 rotating hollow cylinders, 1000x1000km each, with reasonable gravity, perfect weather, safety from radiation, and sustainability for billions of years. The total usable area will be 1e11 square km, 196 times larger than the Earth. It is also portable and redundant, ensuring that the entire civilization is not wiped out by an asteroid. It can remain usable after the Sun burns out; you can install a fusion generator and mine Jupiter for fuel for a very very long time. So tell me again why we need a planet?
While tool use is certainly probable in an aquatic species that evolved intelligence, I would doubt that any such species would progress past the stone age in terms of technology. However, they may evolve a very advanced society, afterall, the Ancient Egyptians and Mayan cultures also were just progressing out of the stone-age yet they had highly advanced societies.
Why would they be limited to the stone age? If you assume that they are fully aquatic and not amphibian-like then they would lack one of the major requirements for progression beyond the stone age. Fire. Granted I may be taking a short sighted view of this, but without easy access to fire, it would be VERY difficult for such a society to develop anything beyond basic stone age tools.
I suppose it would be possible for them to utilize a volcano as a source of energy to smelt metals. But I would imagine that smelting in an aquatic environment would have some severe drawbacks. (even if we ignore the problem associated with oxidation of metals)
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The problems with technology that regular aquatic races have would be even worse on Europa. Imagine an explorer trying to see what was beyond that great ice wall at the top of the world. After managing to chisel through miles of ice, the intrepid explorer would be rewarded with a quick death by blowout as the tunnel opened out onto the surface...in vacuum.
I don't think we're going to be seeing many Europan astronauts anytime soon.
____
~ |rip/\/\aster /\/\onkey
With regard to the creativity mutation: As I recall, there was a proto-human homonid that DID use tools, but never developed on that tool (The stone axe they used at the beginning of their existance was the same stone axe that they used at the end of their existance) And that period of time wasn't short, something on the order of millions of years where they used the exact stone axe.
I believe the specific hominid you are referring to is Homo Ergaster (Working Man).
While they were using a tool, there was no real thought behind it. In that respect, it seems that it was much like a spider's web, a very precise tool for survival but instinct rather than a developed idea.
I don't know if I agree with that assessment. It seems to me as if H. Ergaster simply progressed as far as his brain would allow, and no farther. A simple hand axe was just the apex of his ability. Looking at H. Ergaster makes me rather worried about the future of our species...after all, we haven't been around nearly as long. What if we run up against an innate limit in our brains, and our technology can proceed no further?
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~ |rip/\/\aster /\/\onkey
Navigation may be an issue:
Holly: Look, we're travelling faster than the speed of light. That means, by the time we see something, we've already passed through it. Even with an IQ of 6000, it's still brown trousers time.
Angleyne: You can't bend that girder - it's unbendable! Bender: Well I don't know anything about lifting, so that ju
Arthur C. Clarke, however, argued that CIVILIZATION, however, could not evolve in an aquatic environment, for the simple reason that you cannot have fire underwater. His interesting theory claims that fire, and our control of fire - has been a driving force in our technology. First the fire we would use for slash and burn agriculture - which while being devastating for the environment over the long term gave many short term advantages to the primitive farmer. Fire to make steam is what drove the industrial revolution. And that same power is still in use today, though we get our "fire" in the form of Uranium, or by burning fossil fuels. Then there is the "fire" from the sky - electricity. Harnessing this particular "fire" would be pretty tricky underwater.
I always thought that was a pretty uncreative comment from such a create fellow. If you eliminate the need to breathe (artificially) underwater, it's pretty easy to come up with a basic concept of civilization.
Algae farms wouldn't be hard to manage with the most basic of technology. Power could be generated from currents turning water wheels. Heat based power sources could also work, such as sea floor hot spots or something using the differential between the warm sea surface and the cool sea bottom. Hard metals might be all but unworkable, but fabric and bone could be made easily with plant and animal life. That would then allow a relatively firm fabric based cage/pen for herding animals. Transportation obviously wouldn't be in the form of a locomotive, but perhaps a system of rapid current tunnels could be worked out. Or maybe the harnessing of larger sea animals.
I don't know enough to determine the rest, but I think the rudimentary civilization is there; tool use, farming/herding instead of hunting/gathering, and the basics of transportation.
Not necessarily. Look at Conway's life cellular automaton. There are many valid configurations within the game that can never be reached without setting it that way to begin with. They are called 'garden of eden' configurations. And given any particular starting configuration, there are plenty of configurations that won't ever be reached. And if you define 'possible' as 'any condition that can be reached from a given starting condition,' then you have constructed a tautology and have not said anything useful at all. You are basically defining possible as 'that which happens, given enough time.'
Put another way, "given enough time, monkeys will fly out of my ass." Now, evolutionarily speaking, flying monkeys are possible. It is also possible, given enough mechanical force, that my ass could be stretched large enough to fit the wingspan of an average flying monkey. But I really doubt that even if you waited around for an eternity, you'd ever see a monkey fly out of my ass.
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
I always found this verse interesting, using worlds as opposed to planets. So why wouldn't there be more than one?
Just food for thought
There are many valid configurations within the game that can never be reached without setting it that way to begin with.
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Conway's Game of Life (which I remember programming on a ZX-80 computer, good grief) is an extremely limited set of rules compared to the Universe's - it specifically doesn't allow for randomness - all configurations of the game can be reached if the initial conditions are randomly set.
For your viewing pleasure
......Our galaxy *should* be littered by millions of civilizations........
/.er has the time to do a rough estimate what the probability is that only these factors be met. There surely are other factors not mentioned above.
Carbon is the only central element we know of that can make the extremely complex molecular constructs we find in living things. A "rock" like ours has to have a minimum set of specifications in order to have life capable of anything we could call "civilization".
1.0 One major requirement that this rock must have no other star closer than about 3.8 light years besides its "sun". Another sun sized star closer than about 3.8 light years would mess up that rock's orbit and make the long term climate there inhospitable to life. Only about half of all the stars in the whole universe qualify on this distance specification.
2.0 The gravity at the surface of the planet must be right. Too strong gravity causes the atmosphere to contain too much methane and ammonia, both very poisonous to life. It also makes it hard to move, especially flight. Too little gravity will produce a planet like Mars with little air and water.
3.0 The mass of that star has to be just right. Too large a star would causes its energy output vary more than living things could stand. The energy output of huge stars is not stable, long term. Any life would be exterminated by cooking or freezing before it could get very far along. A too tiny star would force that rock to be too close to its star to get enough heat for life. This would mess up the rotation time, tending to make a day and a year about the same length, such as the planet Mercury. Also there would be excessive tidal forces that would be hard on higher civilized life.
5.0 The rotation time of such a rock could not be too different from that of our earth. If that rock rotates more slowly, then everything would freeze solid every night and cook during the day. A faster spin would make for terrific storms in the atmosphere all the time, preventing the formation of higher civilized society. The rotational speed of Saturn and Jupiter are very high and the winds in its atmosphere are phenomenal. (hundreds of miles per hour)
6.0 Ratio of oxygen and nitrogen in the atmosphere is critical. Too much oxygen would make life functions run too fast and allow any fires to burn whole continents over in devastating fire storms. Too little oxygen would not allow much meaningful activity, because life processes would proceed too slowly. Any other gases, if present in more than trace amounts could also prevent the development of life.
7.0 The crust (outer solid layer) of such a rock has to be the right thickness. If it were too thick, most of the oxygen in the atmosphere would be tied up in it, leaving too little free for living things. Too thin a crust would result in too many severe earthquakes and volcanoes would make it quite difficult to develop any advanced civilization. The crust of our own rock is thinner than the skin on an onion at the relative scale.
8.0 The chemical binding energies of carbon dictate the wavelengths of light needed by living things (photosynthesis in plants on our own rock) that convert the light from the star into a suitable form to knit hydrogen, oxygen, nitrogen, carbon and other elements together as building blocks and fuel for all life forms. The spectrum of that rock's star must therefore be pretty close to that of our sun. Blue or red giants or dwarfs need not apply for the job.
Conclusion: To get a suitable rock upon which a civilization can develop and flourish requires a number of fortuitous "coincidences". On a random basis, this makes the chance of another rock like ours very small. Maybe some enterprising
All theory is gray