'Megascale' structures that humans could one day build
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https://en.m.wikipedia.org/wiki/Aria_(manga)
It is a slice of life story about a grouo of gonodoli riding turist guides in a replica Venice on terraformed Mars. You can see terraformed mars quite often in SF, that's not what I'm talking about. Not even the flying islands that hist the power sources keeping the planet warm.
You see in tgis story, there is one thing kinda hiding in plain sight - it's terraformed Mars with Earth strength gravity.
Yes, not 1/3 g but full 1 g and they did it during the terraforming, it's not a mistake by the author.
So how exactly do you triplicate planets gravity withou importing 2 times of it's mass in the proccess ?
By buikding a Mars spanning series of particle accelerators that accelerate dense macroscale objects to near lightspeed under the surface.
Thanks to the theory of relativity things behave as they had much more mass as they approach lightspeed, which is exactly what you need to simulate two more Marses of mass needed to achieve 1 g like on Earth - bam, artificial gravity using known physics! :-)
Just don't thing about the insane amount of energy requured to accelerate so much muss in your accelerator racetracks to lightspeed. Or what would happen if even just one of these superlaminar dense capsules anaged to collide with the accelerator wall, making all other crash as well. Very close supernova might seem like a firecracker in comparison.
If you can do that, terraforming Mars is nothing, you could just grab a bunch of nearby asteroids or a planet or two and combine.
And just think about how much material you need in order to build a collector large enough to entirely encompass the sun - it's WAY WAY WAY larger than your added Mars mass.
Also you would need a magical strength material just to hold those lightspeed objects in place (think of the huge centrifugal force they are generating). There's nothing in the world that could hold them in place.
I assume they are charged - or how are they keeping them in their "track"? No physical material could handle it. So they have to be charged, well the Synchrotron radiation generated would be enough to sterilize anything nearby.
So "known physics" is a bit of a stretch.......... :)
They effectively play the whole planet using their inner understanding of the system and perfect musical hearing, keeping everything in perfect balance and harmony.
(There are actually some other "engineer castes" such as the Salamanders that live on the floating islands and keep the ppanet warm. They are much less baddass but still rather hot blooded for some reason.)
After wandering around for an unspecified while he encounters a cyborg scientist looking through some sort of instrument. He tells him this "room" in the megastructure is a spehrical empty space and has the inner diameter of Jupiter.
So if you ever wondered where to Von Neumann construction bots that got a little haywire got all the raw materials...
Creating enough mass from energy to hit ~2/3 earths total mass is several orders of magnitude larger than the Death Stars main weapon. And as you point out if basically anything fails all that energy gets released on Mars.
I like hard science fiction that's based in known physics, but I can still enjoy science fiction that's not totally realistic as long as it's at least consistent with itself and doesn't contradict known physics out of pure laziness or ignorance.
I think it's a better solution than just saying "Mars is at full gravity because of magic we won't explain."
Similarly, you get a lot of knock on effects from the other hand waves.
I disagree. That's the fun thing about scifi. As long as your idea could theoretically work (which you seem to agree), you can decide whether the theoretical risks manifest or not, or handwave uninvented solutions to those.
Scifi is about dreaming within our universe beyond our current knowledge or limitations.
At least that's my two cents.
Edit: Not familiar with this specific book, but just in general terms.
Well no their are a host of issues beyond safety and energy requirements. You’re not going to be able to contain that much virtual mass moving at near light speed. We also don’t know if virtual mass produces gravity, etc etc.
Yes we do. It does.
Gravity is produced by energy, of which mass is only one type.
Unless you have a citation?
Basically any other answer would be a violation of a whole bunch of conservation laws. In short: It's easy to convert velocity energy to rest energy, rest energy obviously has gravity, so velocity energy must as well.
Which is completely ok as long as there is some experimental support.
> It really breaks relativity for all forms of energy to produce gravity.
It does not, quite the opposite: It's a fundamental feature of it.
> Which is completely ok as long as there is some experimental support.
There is no experimental support for black holes either, it breaks physics far less for black holes not to exist. (Note black holes are not the same as super massive objects, which do have experimental support. An event horizon has never been observed, just assumed.)
I don’t mean this as an appeal to authority, just a suggestion you likely have some fundamental misunderstandings. Especially if you never worked through the actual equations.
Yes it is, but the lack of understanding of black holes is also part of general understanding. Physicists know quite well they don't fully understand what happens in every black hole situation.
> It’s fine to suggest they don’t exist, just realize you’re disagreeing with the vast majority of physicists and evidence we have.
We don't have any evidence, only conjecture and [incomplete] math.
Two things that might prevent black holes: Quark degeneracy pressure (unknown, not even the magnitude is known), and time dilation, which leads to "frozen stars" which hover just before becoming black holes, but never do because that last bit of mass that takes them over the edge takes an infinite time to arrive.
Neither of those two are "fringe" theories mind you, they have both been discussed by prominent theorists (I also get to appeal to authority :)
First, a quark degeneracy pressure is irrelevant for the existence of black holes as they have lower density requirements the larger the event horizon. A large enough uniform density sphere of say styrofoam would form an event horizon.
In terms of evidence, “Frozen stars” don’t match up with the Laser Interferometer Gravitational-Wave Observatory’s observations that suggest a collision between a black hole and a neutron star.
That said, the Messier 87 black hole image is the closest thing to a direct observation we have. It’s possible that some mistakes where made, but many would argue it’s solid evidence on it’s own.
PS: Anyway, I am not suggesting this as some statement from on high. I am saying if most people that take serious time and effort looking into something all come to the same conclusion it’s prudent to dig deep before coming to a different conclusion. That’s especially true of physics where actually understanding the math behind existing models is difficult. Essentially you should be able to point to some math and say see this, this is wrong and then justify that statement.
All those moons - just like the central planets, they're as close to Earth-That-Was as we could make 'em: gravity, atmosphere, and such
but never provided any explanation. In that medium (live-action TV) it's just handwaving around the production difficulties of showing low-G; Joss by his own admission will cry if you ask him science questions.
For example, in the pilot episode, they pass by a Reaver ship while enroute to another planet. The encounter occurs slowly enough for the crew to get a long look at the Reaver ship as it passes. The closing speed seemed to be about 100mph at best.
Whereas with the Apollo mission to the moon, the capsule was traveling 25,000 mph, or ten times the speed of a bullet. And even then it took three days to get to the moon.
And even 25k mph is slow if we're talking about crossing actual interplanetary distances.
I don't know if it's "particularly bad" by the standards of screen SF. No shows do it well, and the vast majority don't even try.
Beyond that, they do treat maneuvering in space with greater realism that most shows.
Frontier: Elite II (the 1993 game) was the same; it was pretty hardcore Newtonian, but the autopilot would only use the front-facing thrusters to decelerate, even though the main thrusters were much more powerful. If you were under time pressure and needed an efficient flight plan, you had to do turnover and deceleration manually and by eye.
One could even say some things aere kess advanced than one would expect - quite a few autonomous weapons, big rotating space colonies (oneil island 3, standfor torus, clarke wheel, etc) or worldhouses. Also no laser/gracer/xaser weapons or long range kinetic energy weapons. And no nuclear bomb pumped lasers.
This seems surprising to me. By the same logic, if an object moved at speed of light it would have infinite mass and unless gravity is not proportional to mass, you would have infinite gravity.
Only progressively closer - 0.99c, 0.999c, 0.9999c etc.
Gravity is generated by energy, and mass is just one type of energy. For example photons produce a gravitational field of their own, and are influenced by gravitational fields.
So yes, energy in the form of velocity does produce gravity.
It can get complicated to calculate though, because velocity in the same direction as the observer doesn't exist, only in other directions (including perpendicular).
A thought experiment: Two huge identical masses are traveling toward each other, and perpendicular to an observer. They collide and "stick" to each other. All their velocity is now rest energy, which obviously has gravity.
But this means that even before they collided they also had gravity (since you can never create or destroy gravity, only move it).
Now rotate the experiment - one mass is traveling toward the observer, and the other is traveling with the observer. This time when they collide part of it is rest energy, and the rest is kinetic (since the observer is still moving, while the two objects stopped each other dead still at a point in space).
But this time, the mass that was with the observer had zero gravity (from the POV of the observer), but the mass traveling toward the observer had more gravity.
But it means that gravity is not a "global" phenomenon, it depends on your POV. And that makes for some difficult calculations if you must account for multiple objects all moving. (For example in cosmology. From my understanding the calculations are so complicated that they are mostly just ignored because few objects are moving fast enough for it to matter.)
Fascinating stuff. So effectively, with "infinite energy" and "unbreakable materials" we could have artificial gravity.
Whenever you have energy, you have gravity. I suppose you could send the energy from elsewhere, then send it back when you don't want the gravity anymore.
Or an other way to see it : they have to annihilate two Mars planet to get enough energy to create gravity on the third one.
No wonder Aria is a perfect slice of life / healing series - any aggressive aliens or other evildoers don't stand a chance agains their rather low profile yet insanely high tech level! :)
We are kind of living that scenario already, the global transport and energy "megastructures" are causing global warming, maybe not as construction but as system with many components. Imagine building something planned 100 years ago when the people of that time wasn't aware of the polar vortex, the gulf stream or positive reinforcement loops, or were not aware of their importance.
Limited impact, controlled/limited side effects, composable for a planned/measured growth, instead of a big cathedral that must be all of it or nothing, may be factors that make some future projects be safe enough.
It is not just being able to draw it and that have an sound math on its factibility. With big enough things, you may have to factor the impact for all of us, on things that are outside the construction itself.
Someone kinda did this; a 1 to 10^100 gear reduction.
Even regular Tungsten would apparently get you through most of the mantle without melting.
Alright, so what can be done about the extreme pressure that deep?
It seems like bulk nanotubes are perhaps the only theoretical material that could withstand the pressure (100GPa)?
Don't have any compressible gases. If we're just sending machines and infrastructure into the mantle, maybe that's possible. If we want to send people it's harder. I don't know if anything like the oxygenated fluid from the Abyss (or the LCL from Evangelion which was more or less the same thing) does or can exist in reality. Or if other problems would arise at extreme pressures.
Your mention of high melting point materials makes me wonder if fiber optic cables could be made that survive in that environment. It'd be an expensive undertaking just to reduce, say, the network latency from North America to Asia.
If we ignore the mantle, building into the shallow crust where it's still cool seems like a reasonable thing to do. I suspect the main reason it's usually not done are the cost of earth removal and reinforcement being higher than above-ground structures, and having to deal with water. It's fun to think about what an underground megastructure would be like, though. Could be as simple as turning an old pit mine or quarry into a below-ground urban center.
In Portland, OR out towards Gresham there's a huge hole in the ground next to the Multnomah County land use planning department that I suppose is probably an old quarry. I like to imagine what it'd look like with apartment complexes along the sides and a park with a lake at the bottom. Maybe a shopping center with a farmer's market, and a light rail stop. Keeping it from flooding would be a huge logistical challenge, though.
This is a really good quote.
Some estimates put Kowloon Walled City the most densely populated place ever. It's where I think seasteading has it's best chance.
A contrary opinion would be Elon Musks Starlink or GPS.
One would be a solar powered water elevator that pumped water from the Pacific into the various endorheic basins in Nevada. These could then be drained during cloudy times or peak hours to supplement solar power.
The other is a causeway along the Antilles islands from Miami to Trinidad that would act as an eastern connection point between north and south America.
> Espejo de Tarapacá (EdT) – one of the most innovative infrastructure projects in the world – is comprised of a 300 MW pumped hydro storage plant that operates with seawater, located approximately 100 kilometers south of Iquique. This project is essentially a large electricity storage system which will eliminate, at a low cost, the intermittency of non-conventional renewable energy – such as solar energy.
But I guess you could get around it by monitoring and clever mixing.
Interesting. I've thought similarly, but for a slightly different purpose. Inland Australia is a massive desert, but there are theories that it was once (at least significantly more of it) a large grassland. Apparently it was mostly destroyed with the introduction of hoofed animals, which pull the roots of grass out as they eat it, as opposed to kangaroo's and other native animals which eat grass without removing the root.
I haven't explored the hard science behind this, but the theory is discussed in the book 'Dark Emu'.
Regardless, it gives hope that the desert could be cultivated in order to support more plants & animals (I'm thinking native rather than for farming purposes).
To realistically kick this off tho it would require huge amounts of fresh water, which Australia sorely lacks.
But we could produce plenty of electricity from solar power, wind power and nuclear power (Australia has enormous uranium reserves and plenty of sun). With cheap power, we could pump and desalinate water into the center of Australia.
Unlike death valley, it's not down hill tho, so it would require long distance pumping.
Interesting to find this project mentioned here which bares some similarities: https://en.wikipedia.org/wiki/Red_Sea%E2%80%93Dead_Sea_Water...
I was thinking of putting several hundred square miles of something dark (black felt or something similar maybe) in the ocean just upwind of a region. The goal is to concentrate solar energy near the surface.
Increased evaporation would increase air humidity, and rain downwind would increase a lot. Seemed like the lowest tech, lowest cost way to convert solar into rain/fresh water on a massive scale.
It's still not perfect but much better than it used to be.
Issac Arthur is a treasure, I wish high schoolers could take a semester of him.
So to anyone unfamiliar with his work, do not let this stop you from watching, it's awesome if you are in to this kind of stuff.
Maybe it's just overconfidence in humanity, but I can't help but believe that we are capable of such feats if sufficiently motivated and able to work together on the required scales.
[0] http://large.stanford.edu/courses/2016/ph240/mclaughlin2/doc...
Here are a few good starting points:
https://en.wikipedia.org/wiki/Megastructure
After the war, he was assassinated by Mossad. https://en.wikipedia.org/wiki/Gerald_Bull
PS: only the Pope’s allowed to use the canon. Perhaps you meant cannon?
Source for that? See plenty about it being as a defense against Iran also. I can't find anything for your claim made.
And I'd be very interested at where you draw the line for the extrajudicial murder of Western military scientists getting their face blown apart in a Belguim street by foreign governments?
Hazarding a wild guess here but if an Iraqi intel agent did this to someone out the front of their house in Langley it would be completely immoral and evil right?
Surely the justification you've made here can be applied to thousands of current and former government employees along with private contractors across the planet?
I'm truly interested if you think this is how civilised societies should interact with each other? The man could have been arrested at any time, he was not in hiding nor unknown to world.
So instead here is a question to you, what should be done? I ask for a realistic answer.
Is there any technological opinion people had in 1972 that would be considered embarrassing by today's standards?
The only thing that comes to mind is that Simpsons quote: "I predict that within 10 years, computers will be twice as powerful, ten thousand times larger, and so expensive that only the 5 richest kings of Europe will own them"
It'll obviously happen at some point, but they were very wrong about the timing.
There's probably lots of examples on the optimistic side too. AI probably counts there.
This is not by the way a specific criticism of Krugman (though I do think too many people, including Krugman himself, wrongly think his Nobel Prize for trade theory gives him expertise in every other subject he pontificates about).
As usual, the non-doers (commenters or critics, places like the NYT) have little perspective on things that can change the world. It's up to us in tech to always have that bright-eyed optimism for what is possible, because we're the ones building it day-in-day-out. Observer critics don't really have a place in this, unless that criticism is coming directly from folks who are meant to be the initial customers/users of technology.
[0]https://www.laphamsquarterly.org/revolutions/miscellany/paul...
https://www.youtube.com/watch?v=hjIci91FRX4
Edit, starships, much larger than buildings above: https://www.youtube.com/watch?v=aTPwbVqU6lc
No affiliation, but fun channel.
https://www.deviantart.com/dirkloechel/art/Size-Comparison-S...
https://youtube.com/playlist?list=PLIIOUpOge0LtW77TNvgrWWu5O...
Anything space based and big enough to rival or exceed planet sizes would take some very interesting engineering and management.
They would take a long time. Technology would advance tremendously during their construction. In fact, their construction might be planned to never end.
The first bits might not even be functional; their only purpose might be to act as a place to build the next bits on to.
Even when we get to the functional bits, they might be designed and built to be replaced, or built over, like Mike Mulligan's steam shovel.
They would also have to be designed and built to be safe even if civilization collapses. An interesting challenge would be to leave behind instructions, constantly updated while we're still around, to any future civilization to be able to "take up the tools" when they're ready.
Actually I think this would be quite small and manageable.
A space shade shades more area as it moves further away from the Earth. Further, the percentage of solar energy we would want to mitigate would be relatively small.
A modest sized shade made of reflective foil, in a solar orbit interior to the Earths orbit, could probably be done quite cheaply.
The moon can eclipse the sun in its entirety.
Mercury is larger, yet barely visible with a telescope when it transits the sun.
I think the opposite of what you said is true.
(What you said I believe is correct in the case that the sun is much smaller than the Earth.)
But there are also other alternatives that could either achieve some level of control over the wether or help the mirror swarm, like aerostats, or ocean heat exchange energy generators [1]. If we build large enough number of them, we can increase convection between equator and pole regions of the ocean reducing hurricanes and increasing rain over Sahara.
[1] https://en.m.wikipedia.org/wiki/Ocean_thermal_energy_convers...