We are alone, get used to it and spend the money on something more useful.
A team of alien-hunting astroboffins has been awarded a grant to search the sky for immense engineering feats that would reveal the existence of astral civilizations far, far more advanced than us puny humans. Lead by assistant professor Jason Wright of Penn State's Department of Astronomy & Astrophysics, the team will use …
"They won't be able to slurp us all, some of us will live to see the bigger universe"
That's what the dodos squawked to each other when they saw the first humans. I'm with LarsG on this - put the money into research on hiding from hungry aliens! Even if they're not hungry, there's no reason (based on Earth experience) to expect technological advancement to correlate with peaceful and benevolent behaviour.
Or they could try getting hold Culturally Bounded Rationality by S Kaur (http://www.opengrey.eu/item/display/10068/457498) where applying Gödel's incompleteness theorems finds that "higher beings" are simultaneously both more rational and irrational than "lower beings." Much as say, chimpanzees would see human actions as being more rational and irrational at the same time.
> Culturally Bounded Rationality by S Kaur where applying Gödel's incompleteness theorems
Applying "Gödel's incompleteness theorems" to crappy cobbled-together, no-pretense-at-having-any-kind-of-consistency,-completeness,-or-mathematical-relevance-whatsoever automatons like the brain strikes me as a particularly retarded, childish and useless undertaking. We are not and never will be theorem provers or instantiations of a mathematical axiomatic structure.
Penrose falls into the same trap, which is a shame.
Wrote : "Can I suggest you read "The better angels of our nature" by Steven Pinker? It is packed full of reasons and evidence why you could expect [technological advancement to correlate with peaceful and benevolent behaviour]"
There is a paradox here. Without having heard of Steven Pinker, considering that humans DO exhibit aggressive and unkind behaviour, we are presumably of lesser intelligence and advancement than those aliens who do not. How therefore can we presume to know how these advanced aliens are thinking or will behave?
Of course human intelligence varies enormously, so perhaps Steven Pinker's is at the same level as these super-aliens, so he knows. However, what guarantee is there that we will not get the dumber and more aggressive aliens reach us first? In 15th-16th century Earth exploration it was not pale-faced philosophers and intellectuals who went on those ships, it was hairy-chested adventurers and swashbucklers looking for loot, sex, carnage and slaves.
I take it you have never destroyed an ant-hill or wasp nest in your garden. Because you intelligently listened to their point of view and spared them?
"Can I suggest you read "The better angels of our nature" by Steven Pinker? It is packed full of reasons and evidence why you could expect precisely that"
Yeah - so's Star Trek. Don't forget that the minute someone else says spend the money elsewhere, everyone always says "Like what? Guns and war and wah wah wah?" Oops - just reread and see you used "could" instead of "should." My carelessness. But to be brutal, that just makes your rebuttal totally pie in the sky ...
Wrote :- "That's what the dodos squawked to each other when they saw the first humans."
For the benefit of those who still think we will be taken to their leader, have a nice chat with him and end up with high fives, you should have told the rest of the story.
When the sailors started clubbing, the dodos, who knew a bit about world affairs, sqawked to each other: "It's OK, we will write a letter to the King. He is a kind man and he will come here and stop it." So they wrote a letter to the King and the sailors naturally promised to deliver it, which they did (but carried on clubbing meanwhile). When the King saw the letter (he could read dodo writing of course) it deeply affected him - he nearly died laughing. Then he wiped his arse with it.
"We have Macbooks that can upload a virus to the mothership."
It wasn't the virus. Steve Jobs realized the aliens had stolen his "technology" and went all thermonuclear on them. The motherships got over run with lawyers and the aliens lost the will to live. Apparently living several million light years away doesn't protect you from American patent laws.
"Even if they're not hungry, there's no reason (based on Earth experience) to expect technological advancement to correlate with peaceful and benevolent behaviour.".
Actually, there are lots of reasons to expect just that. The most obvious is that technologically advanced civilisations of the sort that might, for instance, be able to build a Dyson sphere have access to and the ability to control huge amounts of energy. The ones that are not peaceful wipe themselves out in wars pretty quickly.
It is a statistical improbability that we are alone in our galaxy, let alone the entire universe.
Disbelievers people say that the conditions for life are mind boggling rare, and intelligent life even rarer still... I'll accept that, but working for that, there are there are 300 Billion stars in our galaxy alone... and ours isn't even a very big galaxy...
The raise of intelligent life could be one in a trillion trillion to one... and there would still be literally countless other intelligent life forms out there in the Universe somewhere...
As for spending money on something better... like what? better bombs? reality TV? pills to make dicks harder? Please enlighten me.
how is it a statistical improbability that we are alone? last time I checked, you needed a sample size larger than 1 to determine anything from statistics... we know of 1 planet that has life on it... not 15, not 300, not 10,000... just one. p-value gonna make your master's thesis explode on that one sample size...
furthermore, why is it so hard for people to just say the words, "I don't know." You don't know, and may never know if there is any other life on other planets, and any statement to the contrary, given our current data is simply speculation.
I'm not sure why all the down votes for OP. Consider von Neumann probes. It's logical to assume that once a civilization has advanced anywhere close to Kardashev II scale, it would send out self-replicating probes throughout the universe. Game theory dictates that it be done, lest it fall pray to another civilization who do so beforehand. It takes less than 1 day of energy output of our sun to send a small probe to every single star in our galaxy! And another day to every galaxy in the universe! This means that the entire universe should already be colonized and divided into territories. We don't see any evidence of that. One of three things follow:
1) We are effectively alone in the universe as the original poster stated (at least as far as advanced space faring civilizations go). -OR-
2) Some of the things we take to be natural cosmology are actually artificial constructs and Sol happened to be outside of any areas of influence. -OR-
3) We're under some sort of protection. Other civilizations are aware of our existence, have a policy to not intervene and would likely prevent us from making any contact.
Occam's razor makes #1 significantly more likely. Other choices involve more entities to explain observations. Hence, I tend to side with OP. At any rate, no matter which of those 3 things is correct, this search won't find anything.
I like your analysis as far as it goes. I think a different culture might be harder to recognize then we give credit. If we were ants, puffed up on our ability to bring down larger insects/animals, engineer, and farm, would we recognize creatures who use sound instead of chemicals to communicate. Would we recognize land use zones and their land ownership.
It's not wrong to look and search, but much that we take for granted today would be missed entirely by someone from a few hundred years ago. Just saying we might be looking in the wrong places for the wrong things.
"Occam's razor makes #1 significantly more likely."
No it doesn't, but that doesn't particularly matter as it's complete bullshit anyway. "Occam's razor" is a a very simple principle stating that among competing hypotheses, the one which makes the fewest assumptions should be selected. It's about chosing the least risky guess - when you have to make a guess. As guessing is not generally accepted as valid scientific method, it has no relevance to the pursuit of knowledge.
Sorry it just gets on my nerves when people start quoting this bullshit principle as if it was the be all and end all. Oh well.. too many people were educated-by-movie these days for it to matter I suppose.
I'm not sure what you're trying to say overall, but your post suggests that I've actually used the razor correctly by selecting from several hypothesis the least risky (more likely) one based on its simplicity. There's empirical evidence of use of Occam's razor resulting in more accurate scientific theories. Regardless, of how you think it works or doesn't, its a useful tool. As to people educated by movies, I completely agree. It's happened to the point that overwhelming majority assumes the existence of aliens with zero evidence to suggest it.
4) My assumptions are wrong - is always a caveat emptor. However, mentioning it on the forum would result in people automatically selecting it without having to do any work to argue against those assumptions. Come to think of it, exactly as you just did.
"It's logical to assume that once a civilization has advanced anywhere close to Kardashev II scale, it would send out self-replicating probes throughout the universe."
No, it isn't. There's nothing logical about it at all. It might - perhaps - be what the human race would choose to do. But there are good political reasons why it might not happen, good practical ones why it might not work or might not use science or technology we're familiar with or would even recognise as such, and good physical ones why we might not have encountered such probes even if a civilisation did choose to use them.
The only *logical* assumption on the topic is that we have insufficient data to even begin to speculate usefully about what might be going on out there, if anything is at all.
Alternatively consider these options:
1.) None of the other civilizations are advanced enough to create these von Neumann probes, just as we aren't.
2.) None of the other civilizations feel the need.
The problem with all these theories is that they assume the all other life thinks the same way we do. I can't see why that should be the case.
Yes, there could be reasons that you curiously avoid mentioning. However, all it takes is 1 civilization close to Type II to colonize the universe and that hasn't happened. So either all of them are subject to the same reasons you don't mention or they don't exist.
I have. The universe is 13.75 billion years old. First galaxies are ~13 billion y.o. All it takes is 1 and it hasn't happened. Moreover, if we go by your suggestion that other civs aren't advanced enough, then searching for Dyson spheres certainly wouldn't be fruitful.
That assumes these other civilizations routinely employ paranoid schizophrenics in their military industrial complexes, and have a pressing need to justify the unjustifiable. yet still maintain the capacity to prevent this train of though infecting their political & financial systems and turning everyone's 401k into shit.
could happen i s'pose :-)
I think your first option falls down, the probability of life on other planets is probably likely since the factors required for life in the universe are very common and as you say the premise is based on a lack of space faring nations.
The fourth option is also probably the most likely in that if other life is based on an evolutionary basis (which is highly probable) then like ourselves it has found it impossible to break out from within its own solar system with manned ships and therefore is setting there having the same stupid arguments and wars as the people of earth.
Maybe the Von Neumann machines do not use the same criteria for selecting target systems as we would. Perhaps they avoid systems with short-lived yellow stars, cold gas giants and life-bearing worlds and instead go for long-lived red dwarf stars with hot Jovians and/or lots of asteroids, and no pesky natives.
Or how about:
4) Civilisations generally don't do this because landscaping an entire galaxy is rude. But it only ever takes one, so perhaps:
4a) Species that engage in this sort of thinking tend to go extinct because they take the same approach towards their home system and hit Malthus's limit before they can spread too far. We may well kill ourselves off before we reach the necessary tech level, for instance.
Using fewer assumptions there are still a few other options:
6) It has in fact been done, but colonising civilisations are sparsely spread through space and time so that we simply missed them. If the last lot in the Milky Way disappeared a mere 50000 years ago, no trace of their works would remain visible from here (unless they left megastructures behind). In fact, we could go extinct again without ever being concurrent with a single other civilisation in the Local Group, even if generally speaking life is abundant in the universe.
7) Colonising the galaxy turns out to be really hard and its history is full of single-planet cultures wondering where all the aliens are. Most go extinct without ever seeing any.
TheUglyAmerican wrote :-
"they could harvest the energy with enough efficiency to not radiate anything. Then again I could be missing something."
Yes, you are missing the Second Law of Thermodynamics.
Heat Death of the Universe icon (for those who understand the implications of the Second Law)
Stars are nothing but a reaction turning matter into energy. I cannot see aliens going to the bother of surrounding a star to capture the output. By the time they reach that level of technology, they will just turn matter to energy themselves and the only way to not have energy is to have no matter.
Seems to be that somewhere sometime in the Universe, Malthus was actually correct. Lol.
I wonder who gets the research grant premised on Leibniz being correct somewhere sometime in the Universe. Lol.
It seems there is too much money sloshing around in research. Why not give some of it back to the taxpayer?
I question the leap of logic for Dyson Spheres, at least in terms of the justification of them for energy harvesting.
Consider our situation: were we to develop cheap, easy fusion power, would we continue with solar panels? If you had a water heater sized fusion plant that produced a steady 100kW of power, with no neutron emission (and thus no neutron activation), would you want solar panels on your house too?
By the time a civilization reaches the technology to be a Level 1, are they going to worry about solar power, or say "screw that, we are using our own fusion power - it's easier!"
Likewise, by the time you reach level 2, are you going to want to screw around with a star, or are you going to have something better (total conversion, say)?
Yep. I would have thought it much easier to 1) harvest fuel off a large planet then 2) fly to another system and repeat. Space has so much "fuel" in it to that extent, no one would need or want to restrict themselves to the building project of a Dyson Sphere. Unless it was publicly funded of cause.
What about keeping the population near the harvested energy? Sounds a littlr like "V" to me, sans "Blue Energy".... But, if the population deemed travel elegible numbers beyond a few hundreds of thousands, you are talking about one cosmic ragtag fugitive fleet, a caravan of refugees that may eventually be seen as space vermin.... Roaming space and stripping planets of energy could become tiring for some who might just decide to stay behind.
Hey, space refugees tired of packing up and just wanting mortality coul be an alternate explanation of our own lineage, not that it is a novel idea....
PBR = Pebble Bed Reactor, for those wondering...
Also, being so close to the star, wouldn't solar flares and such just obliterate the thing every now and then?
As has been said, if the civilisation is that much more advanced than we are, they've probably figured a much better way to generate/capture energy.
There's also the fact that the light from anything we do see is millions if not billions of years old so the civilisation is probably long since dead, if not their entire solar system too.
Well, I think there's a lot to be questioned here in my opinion. The theory of a Dyson sphere isn't that illogical, but the amount of resources you'd need to get there are enormous..
Which brings me to another idea... Why do we assume that these Alien species harvest energy in the way we would? Why couldn't they have totally different means of collecting and using energy instead?
Its a bit far fetched, and probably stupid, but a few months ago scientists discovered a huge cloud of gas surrounding our galaxy. The gas is said to be of high temperature thus it contains lots of energy. How certain are we that this was a natural phenomenon? To my knowledge (but I don't keep up with these developments) such clouds weren't discovered before, not even when observing other galaxies.
Now, I'm not insinuating that such a cloud was actually created by Aliens. But why couldn't such a cloud be used by such a species as a source of energy?
Because the cloud is very, very diffuse. It's just that it covers a huge volume so constitutes a large mass and seems to be in the right place to be at least a significant chunk of dark matter. Also individual molecules being 'very hot' in intergalactic space do not a convenient energy source for galactic planet based civilisations. It would be a bit like me installing solar panels on a patch of Pluto instead of my roof and beaming the energy at the house with microwaves.
Into this calculation should be that space missions beyond Jupiter use radioactive energy generators instead of solar panels, the light from Sol being too puny for the purposes that far out. It's why the two Voyagers are still working for eg.
Great questions... but given that we are quite a few million years away from clean portable and emission-free fusion power - assuming those are even possible, given the restrictions of physics - I have to wonder about the possibilities of energy capture, an effective concept proven by billions of years of evolution and responsible for all biomass on earth.
After inventing the neural-net processor which lead to the Rise of the Machines, he worked selflessly to overthrow the Combine as his penance.
Also, we already have proof that advanced alien civilisations have built Dyson Spheres. Where do you think all of the universe's missing energy is?
El Reg is obviously slipping since the dimensions of a Dyson Sphere was not given in standard units.
Fortunately, I can reveal that it would be approximately 5000 YottaJubs, and (assuming a radius of 1 AU) would have a surface area of nearly 14 TeraWales and a volume of 5,600,000 Yotta Olympic Swimming Pools.
Unfortunately the SI scale breaks down at Yotta (10^24). Someone really needs to come up with a bigger prefix.
Dyson spheres are cool enough to be a unit of measurement themseleves. So in el-reg units the size of a dyson sphere would be 1 dyson - can't get simpler than that.
It may however cause confusion if we also use it as unit of suction (perhaps we should use the 'Paris' for that).
Harness the energy of multiple universes? How does that even make sense? Do you just lay a cable, then see energy in the Big Room appear from nowhere until the energy/mass content is locally so high that you big crunch this universe? WTF???
Anyway, we cite Stross...
“Hmm.” Sagan is busy with a mouthful of delicious tetrodotoxin-laced meatballs. “It’s clearly a Kardashev type-III civilization, harnessing the energy of an entire galaxy. What else?”
Gregor smiles. “Ah, those Russians, obsessed with coal and steel production! This is the information age, Dr. Sagan. What would the informational resources of a galaxy look like, if they were put to use? And to what use would an unimaginably advanced civilization put them?”
Trouble is... as Niven admitted, the material you make your ringworld from would need to have a tensile strength approaching that of the strong nuclear force.... Although I guess you could spin it slower and reduce the load somewhat , if you dont mind having less than 1G of force holding you down.
Oh and dont forget the attitude thrusters either
The tensile strength would be utterly insane at any speed that would keep an atmosphere in I imagine...
centripetal accel = v^2/r if memory serves, and earth orbital radius is 150 x10^9, so to get 10m/s^2 at that distance you'd need a v of root 150 x10^10, about 1224744m/s, or half the target gravity would only need root 75 x10^10, still a rather weighty number. Any less and the weather would be inclement and brief I would imagine.
So there probably isn't a velocity that would keep air in without coming apart, regardless of r and any material we could invent. I could have a go at working out more but it's friday night (see icon)
I've not read the Bigger Than Worlds essay but will have a look, thanks!
They're smaller (which means less tensile strength), and you don't need the sun in the middle with those bloody shadow squares. Orbitals rotate, but you tilt the axis at an angle to the sun, so you get night and day for the inhabitants. Orbitals sounds a lot more fun - more benevolent robots and less Slaver sunflowers.
I don't want to know what a Kardashian Level II civilisation would look like :p
But seriously, we're not even type I on the scale. A type I civilisation can produce the power output equal to an entire planet, we're no where near that. Maybe in a few centuries, unless we get a break somewhere in energy production.
no we're not - a type I society can harness the power of the entire planet in an efficient and non-polluting fashion. imagine being able to harness the power of all the world's oceans, winds and rotational forces - we would have massive amounts of energy at our disposal and the world would be a much much better place than it is now. we are only just starting to even investigate these possibilities - about the most generous level of civilisation i've seen attributed to the human race is type 0.5 but most knowledgable people would argue with that. we're perhaps a type 0.25.
"imagine being able to harness the power of all the world's oceans, winds and rotational forces"
Hmm, I've imagined all that for a second... then had to imagine all the dead fish and birds, the Earth rotation dramatically slowing and all the earthquakes and eruptions it caused.
I think we should stick to burning stuff, splitting atoms and/or fusing them back together...
While I applaud the research, I honestly doubt any civilisation would ever construct a Dyson construct... for the simple reason any civilisation capable of doing so would be so advanced they wouldn't need to build one.
Actually stretch that... I could see humans building one if we could... just so we can brag about it...
In engineering form follows function, but in technological evolution, function follows form.
Why would a sea-based life form discover fire? Gun-powered? Combustion? That rules out an entire tech tree that leads to space.
Would a species with a genetic memory develop writing? if not how would they work with complicated equations?
It all comes down to the idea that in order for a species to reach space they have to have SOME things in common with humans.
"Why would a sea-based life form discover fire? Gun-powered? Combustion? That rules out an entire tech tree that leads to space."
Somewhere on another planet right now, a eight-limbed creature is posting: "why would a land-based species discover steam-power if they didn't originate or just water-wheels powered by hot-water currents, if they hadn't evolved around volcanic vents underwater?" All that is needed is an energy source and the means to harness it. Once you've crossed that particular Rubicon, you're on a path you can't go back from. Our underwater civilization might even get to Space first as they'd be used to a 3D environment (assuming they swam) and they'd be used to thinking in non-2D movement.
"Would a species with a genetic memory develop writing? if not how would they work with complicated equations?"
A species with genetic memory would essentially be equivalent to a very long-lived organism. In either case, maybe that long-life would lead to a faster rate of technological learning (or slower). We don't know because it's one variable in isolation.
Not down-playing your points - we have no idea what we ourselves might have missed simply because we have our own limitations and assumptions. But equally, that blindness might lead us to arrogantly assume that our path to the stars is the only one.
Here to observe, but stuck around for the exspheriance and smoked a few and the chemical interaction bried his frain, inducing him to surt specrets in incoferent hashion. Some enterstrising apronomer hicked up on the pints and and ran with a few clopped drues.
I wonder how big a Dyson Bong would be...
(Clisdaimer: i am not poking smot, and i don't drue dugs)
Would be at the radius of the originating planet (ours would have a radius of 93 million miles). It would allow 100% energy conversion. If our technology couldn't handle that much energy it could be radiated into space by heat sinks. My problem is that any civilization that could construct a Dyson sphere - why would they want to? If you control enough energy to construct a Dyson sphere, then you don't really need one. That would be the kind of thing that might happen in an entropic universe at the end of its life. To address one more of the previous points, there is a possibility that we are the first intelligent species to arise in our galaxy - note that I said first, not only. If we were the only, then maybe there is a ?deity. If we are the first, then we should set an example by not spewing the waste products that pass for entertainment, all over the galaxy. Now if you'll excuse me I'm going to make another rye and coke (and my buddy seems to be doing something with some cigarette papers).
they are the future and cuts global co2 emissions by 99%, you can put them in old mines, in custom silo`s, in power plant carparks, anywhere at anytime and get power for the national grid without enviromentalist complaining, and power companies saying green electric costs too much and so on and so on
no advanced civilization would make a sphere, having a fustion reactor in orbit of a sun is more practical, or just magifying a beam into a laser
off shore http://www.repower.de/wind-power-solutions/wind-turbines/6m/ = 6.15mw
6mw = 6000kw http://www.aqua-calc.com/one-to-all/power/preset/megawatt/6
a 500w motor can doo 1000rpm, not 20 offshore turbines need for max output, generated electric goes to a AC and loops back to the motor, you just need a external power source to start them up, when they are able to power themselves, you cut the external power source
probaly or they would already exist...
wind farms only produce 2% of green energy for the national grid, if the world wants to cut co2 levels for 40% in 10 years, then the only way todo so is to have self powering dynamo`s,
if you put a motor on a current wind farm turbine that generate 6mw every minute with constant generation using a motor instead of wind, then wind farms would being giving the national grid 16% green enerage to the national grid
if you have a domestic wind turbine that generates 10kw, and put a 500watt motor on, then you can power you house and have a bit spare to give to the national grid and get paid for the extra electric you generate
its all just a simple bit of math, and the power of motor and torque to need to mimic wind and make a turbine generate maximum output at optimal speed for the RPM
electric motors are the only way you can turn massive axles, as soon as the dynamo starts to turn its generating power which 2% loops back to powering the motor, and the rest goes to the national grid, when the turbine is generating maximum output, then they can power themselves and you diconnect from the external power source which would be the national grid or a solar battery cell
is better looking then a wind farm turbine, in power plant carparks, with the electric motor bolted on top
i assume you post on dnba and just trying to be posh
a wind turbine is just a dynamo being turned by the wind, like dynohubs powering lights on bike in the 80s from the turn of the wheel
wind turns the axle with turns the dynamo, a electric motor can turn the axle which turns the dynamo, a electric motor with the power and torque to mimic wind will not use 6mw of electric to power it
This post has been deleted by its author
12volt motor with a 13 amp fuse is still only 156 watts using http://www.jobsite-generators.com/power_calculators.html and the same on http://www.rapidtables.com/calc/electric/Volt_to_Watt_Calculator.htm
which still gives you 9844 watts to go else where, with a constant source of 10kw being generated using a electric motor, with a power drill would just be wasting extra power having to much RPM and torque
if 10kw is generated from 20 turns of the dynamo, then 500watt is generated every rotation which can still power the motor and have 344 watts spare,
As Bob Shaw note they have *huge* surface area, so you'd have to work very hard to run out of living space.
And all structures make statements about their builders. A Dyson sphere (like the one in Orbitsville) says
Know our power.
Although as others have noted the structural stresses of a *true* sphere, rather than a (large) number of panels would be immense. While it's quite likely any such builders would have more compact power sources available having a growing population might be a more pressing issue *assuming* you have an expansionist culture. The amount of solar energy captured by the part of a single planet facing a sun at any given point in its orbit is *tiny". Run the calculation for our Sun and just the amount *wasted* by radiation out of the ecliptic hitting *no* planets in the Solar system is immense.
Building a huge structure around a sun seems like an insurmountable task. I would argue that it would be much easier to just create a smaller, artificial sun within a container harvesting it's energy. This could then be placed safely outside of your home planet, so that if things go wrong, nobody gets hurt.
Besides this, enclosing your sun in a structure would put your planet in a bit of a sticky situation: less solar energy reaching it, temperature will decline, among other problems.
That's one of the main criticisms of Dysons' ideas (one he himself brought up IIRC), the idea that any race that had the knowledge and capacity to build one, would be so staggeringly advanced they wouldn't have the need to build one (beside bragging rights).
But on the subject of harming your planet... not so. If you build one in our solar system, you'd do it out near Jupiter's orbit, the Earth, Mars, Venus, Mercury, would be INSIDE the sphere and it wouldn't have much impact on them at all.
The shear amount of living space of a Dyson construct is really hard to get your mind around, you'd have land equal to billions of Earths, capable of housing hundreds of trillions of people without any crowding at all... Hell it would be like Earth with only a few million people living on it... It's brain hurting.
Though you'd need a lot of people outside bringing you raw materials to keep the civilisation going... that's stripping mining on a stellar scale kind of stuff... Hell you could dismantle every planet in our solar system and still not have enough raw materials for even a small percentage of it...
A Dyson sphere wouldn't even be particularly difficult once we (or anybody else) develop self-replicating machines. Send a single machine to e.g. jupiter to start converting its moons into more machines that launch themselves toward the sun and form a giant swarm of (super efficient) solar panels. They would need to get much closer than, say, Venus orbit. The machines in the swarm could be close to each other in the order of meters and they could beam power toward Jupiter to feed the machines being made there (machines beam power to each other and relay it to a central point on the sphere where it is then beamed toward Jupiter or whereever).
Thus progress on the sphere would be exponential and therefore done in a jiffy. Once complete they would beam the power where ever we want it.
I say there's a good chance we can do that in a century or so (remember, we 'just' need self-replicating tech to do this).
It's wonderful to think that after all those years of apparent dedication to the ideals of science, coupled with perseverance, endless scientific study, exams,MScs, PhD research etc. etc these guys are happy to sit back and slurp up a big grant for a load of old cobblers.
It just makes me proud to be human.
"No matter what form they might take, they'd undoubtedly give off infrared radiation that could be detected by such sensitive sensors such as those aboard WISE – and that's where Wright and his team come in."
So we're assuming that such an Alien nation actually has the means and skills to build a Dyson sphere, but immediately conclude that they can't be advanced enough with chemistry to have invented an alloy capable of complete absorption (or at least one which doesn't waste any energy at all) ?
Sounds like a very flakey assumption to me.
ShelLuser wrote :-
"So we're assuming that such an Alien nation actually has the means and skills to build a Dyson sphere, but .. can't be advanced enough .. to have invented an alloy capable of complete absorption (or at least one which doesn't waste any energy at all) ?"
Yes, we are assuming that. Unless they have found a way to suspend the Laws of Thermodynamics. Energy cannot be destroyed and eventually all of its forms degrade into low grade heat that you cannot do anything more with. That low grade heat being dumped outside the sphere is the infra-red radiation being talked about.
Thermodynamics is the one theory we can be most certain of.
Namely that you can't get something for nothing - you can only get usable power by letting heat flow between a heat source and a heat sink, and the smaller the temperature difference between them the less useful work you can make it do.
As far as we can tell the only way this can change is if you can use another universe as your heat source and/or heat sink.
While I have the utmost respect for the laws of thermodynamics, there is one thing that I would point to, that might make it at least slightly plausible that a sufficiently advanced civilization could find a way to circumvent that law.
I would point to the universe itself. Whenever someone debates this topic, someone usually mentions the oddity of something coming from nothing - be it the universe coming from nothing, or some deity [who created the universe] coming from nothing.
There might be a perfectly good explanation to the universe - that doesn't involve something from nothing - but it is also plausible that there is some process or other that allows something to arise from nothing. If such a process is possible, then it is surely exploitable with sufficiently advanced tech.
So yes, in order to respond on a heavily debated topic with no chance of a sure answer, I am referring to another heavily debated topic with no chance of a sure answer [both being restrained only by our current tech development]
"There might be a perfectly good explanation to the universe - that doesn't involve something from nothing - but it is also plausible that there is some process or other that allows something to arise from nothing. If such a process is possible, then it is surely exploitable with sufficiently advanced tech."
There is. Check out Hawking Radiation. As to the means of exploiting it, you need a handy supply of Black Holes.
"Also if assuming a radius of one AU, then there may not be sufficient building material in the Solar System to construct a Dyson shell. Anders Sandberg estimates that there is 1.82×1026 kg of easily usable building material in the Solar System, enough for a 1-AU shell with a mass of 600 kg/m²—about 8–20 cm thick, depending on the density of the material. This includes the hard-to-access cores of the gas giants; the inner planets alone provide only 11.79×1024 kg, enough for a 1-AU shell with a mass of just 42 kg/m²."
Well, we are talking Magical Tech here of a full, solid sphere, so you can go with anything. Maybe structured spacetime, who knows?
Even our puny civilization has built aerogels and metallic microlattice materials that have densities of under 1kg per cubic meter (excluding any trapped air). Use something like this for most of the bulk of the sphere and you have plenty of mass left for the support struts, PV panels, greenhouses and whatnot.
Regarding the tensile strength issue. Surely most of the surface area will be dedicated to harvesting energy in one form or another, which requires neither gravity nor general atmosphere. So you don't need to spin the whole sphere, just the bits that require gravity. An array of spinning earth-diameter mini rings (with lips on the inner edges to contain the atmosphere) orbiting just inside the sphere could handle any needed 1G real estate.
I certainly commend the efforts to investigative and identify if there is anyone (anything?) out there capable of building a Dyson Sphere which would certainly be an awe inspiring moment if indeed we could identify one, (I too am of the belief that if they were advanced enough there would be ways of hiding the emissions, yes, yes laws of Thermodynamics and all but I have no doubt we as a species haven't plumbed all the secrets of the universe yet so don't discount there are other ways we have to discover that may break those laws.. but I digress), but here is another thought of mine.
What if we are not alone but in fact the one species that has managed to progress/advance quickly enough to this level, taking that one step further ,(and whilst we postulate that the universe is old do we really know how many billions of years are left, i know we can guess/calculate based on matter decay etc but I refer to my earlier point of not knowing everything yet.), perhaps we will become the first KI,KII & KII or KiV species! we could become that "ancient" species that develop all the cool toys ..
Anyway just a thought, would explain why we can't seem to find anything just yet.. Could also be because space, is really, really big.....
It is extremely difficult to imagine how it would look a civilization far more technologically advanced than our own. Such an advanced civilization might be able to extract energy from the vacuum, they would have total control of gravity (they could create artificial gravity), so they could build artificial worlds not related to a solar system, artificial worlds that would "work" in the vast space between galaxies where there is no danger of cosmic collisions, black holes, supernovae, etc.
Be prepared for unforeseen circumstances... .... Anonymous Coward Posted Monday 8th October 2012 08:39 GMT
Events, dear boy, events, ...... by another name, is IT ever so sweet. Although if events and clearly foreseen circumstances have been freely shared, such as may be viewed and peer reviewed here, and are plotted for a much smarter reworking of a villainous Zorin type Bond movie, which may all too easily be able to be an actuality and current reality, as mused upon by the Register here ....... they cannot be heralded as being unforeseen whenever they have been rather more stupidly ignored by intelligence services which just don't come anywhere near being able to cut the mustard in these novel virtual times.
Although that is not to say that there are not many who be trying to get to grips with intelligence explosions and information overloads which they would no controlling power or empowering control over, for IT is certainly a frenetic and some would even admit, quite supremely psychotic field of future great games play ........ as this lively little article would suggest ....... http://www.israeldefense.com/?CategoryID=483&ArticleID=1676
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