Comment by alkonaut
4 days ago
If we do the fusion in zero g then we have solved the confinement issue. The problem is creating conditions for fusion in zero g. The simplest way would probably be aggregating enough material to a single spot that gravity itself creates conditions for fusion. But then the power plant becomes too energetic for earth so it has to be at an enormous distance away to be safe. And with that of course you have the problem of transmitting the power back to earth. But I think photons could be gathered at a safe distance from this fusion, to harvest it without having to be so close.
The issue with that is how to direct the energy back to Earth, and then collect it. If you can’t direct it and it radiates in all directions then only a tiny fraction of the produced photons will reach Earth. Then you need to collect those photons in order to do useful work, otherwise they will just heat the earth. If the distance needed to remain safe is greater or less than geosynchronous orbit, you’ll need collectors all over the Earth as they won’t have constant line of sight towards the source and experience a “nighttime” of sorts. There is also the issue of atmospheric effects, such as high densities of moisture, absorbing or scattering the photons, reducing the efficiency of the collectors. So it could work, but the effective maximum capacity will always be quite limited and the overall process highly inefficient relative to the total fusion energy produced.
Actually you don't want the transmission process to be 100% efficient. If you really captured all the fusion energy transmitted (or even just the small part of it reaching Earth), all sorts of people would complain, trust me! But fortunately that fusion reactor has more than enough power to go around...
If only it were smaller and closer. We could make it smaller by using a force other than gravity to compress the matter. Perhaps a very strong magnetic field? If it was strong enough you’d only need a fraction of the matter.
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> But fortunately that fusion reactor has more than enough power to go around...
"All the energy we could ever use, forever and forever and forever."
"Not forever,"
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They wouldn't complain for long though
How about we use solar panels to collect that energy? And then we add batteries to fix holes in supply when the panels can’t see the power source.
That sounds great, but those batteries are both too expensive right now and not available. People choose the cheaper alternative which are to use thermal energy where they burn gaseous hydrocarbons when the panels can’t see the power source. When the time and price is right we may stop building new such thermal power sources, but for now we can define them as the current best choice and even call them green since everyone has the intention to replace them in the future some day.
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I think you are on to something here
> The issue with that is how to direct the energy back to Earth, and then collect it.
‘Simpler’: move earth to where the energy goes: https://en.wikipedia.org/wiki/Dyson_sphere
Maybe we can use the excess photons in another way? We could bio-engineer sunlight collection devices that would take in sunlight and use it to break apart CO2 and produce other useful materials. We could then spread them around the planet to use the excess photons in a productive way. We gain valuable complex molecules and break down CO2 so a win win!
Hm, it could be possible to engineer devices that use the excess photons reaching Earth along with environmental CO2 and H2O to assemble sugars and other carbohydrates. Depending on the specific reactions, we could even end up with O2 as a by-product, which would be additionally useful for us.
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There may also be a side business selling skin products to protect people who may be exposed to the radiation from this new reactor. Possibly people may even choose to vacation in areas of elevated radation, as it is likely to be warmer. Interesting...
And another side business selling tanning beds.
If you only have one of them then the photons would only be available on that side of the earth at any given time and the other side wouldn't have power, but two of them would confuse the animals and disrupt everyone's circadian rhythm and then you'd have to deal with the three-body problem. Even the reactor-facing side would also have issues with the photons not getting through when it's cloudy.
The photons will also create heat and that heat can be used for useful work at any time, even when there are no photons hitting that side of the earth. For example it will evaporate water which will later condense into rivers, where you can put turbines. So it's a kind of fusion power, but less direct. Pure science fiction, of course.
The energy density of gravity-based storage is very low, so it could work in places where you have mountainous terrain and a lot of cheap land, but what do you do after the sites suitable for it are already in use? To make that work you'd need a scalable storage technology with a low enough cost per kWh of capacity to economically scale to multiple TWh of storage in case it's cloudy for an extended period of time.
For example, if you could make batteries at a price of $115/kWh, the cost for enough capacity to sustain the US power grid for a week would be around 24 trillion dollars, and that's just for the batteries and not any of the associated electronics or the land or the photon collectors themselves. It seems like to make your plan work you'd need a scalable storage technology with a significantly lower cost per kWh of capacity.
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Three Body Problems are only systematically unsolvable, you can still numerically calculate and manually move them with some algorithm.
A huge fusion reactor at an enormous distance away... isn't that the sun? :-)
It looks like ultimate goal of this is creating a self-sustaining fusion reactor approximately 1AU away from earth (for safety) and using photovoltaic arrays to absorb the energy... Ingenious!
This truly is a miracle of modern science, something we could only accomplish in this day and age.
yes, exactly, no need for any fusion reactors in space. Collect space solar energy and beam it back to earth via microwave radiation.
Space solar is an old idea and the Soviets/Russians have worked on it since the 70's; and nowadays, like most other Russian inventions the Chinese are commercializing it. https://www.ft.com/content/2d43ed21-9f9d-4e90-a18b-ad46f0a47...
That's what OP was implying. Energy (..and its derivative global warming ) is just infrastructure and finance problem now onwards. Balancing grid, Moving power from sunshine area to non-sunshine area, storing some power at night, handling fluctuation all are more or less solved problem. Fusion is just research subject ( ..or for may be powering colony on mars ? ). ..... saying that, I hope our collective curiosity for fusion will take us to new inventions and space opportunities.
> If we do the fusion in zero g then we have solved the confinement issue.
If me move the reactor close enough to the center of the earth, eventually we can get to zero g. We then also solved the confinement problem.
…is this an elaborate joke about solar power? And by extension, virtually all the energy that’s accumulated on the earth over the eons? It took me a minute :)
I thought it was obvious but apparently not. Sarcasm is only funny when not tagged with the /s.
I certainly got a laugh! And I agree about the /s. Chalk it up to this reader’s slow mind on a slow day!
In a forum where people credulously propose orbital platforms to “sell sunlight at night” [0], I find myself erring on the side of assuming seriousness…
[0] e.g. https://news.ycombinator.com/item?id=42995403
A majority of the people on HN think there is an explicit no-humor policy. Judging by the fact that a lot of people here are genuinely confused when they come across something really funny, I can see why they try to pretend humor can’t insightful, useful or informative. It saves them from embarrassment.
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I find that many younger people have a hard time 'getting' sarcasm and irony when it is not explicitly pointed out. I wonder if it may be due to the prevalence of '/s' in online discussions, or if something else changed.
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Try building a structure around the fusion source: https://en.wikipedia.org/wiki/Dyson_sphere
beam energy down to the earth from space? My god man, did you learn nothing from Sim City’s microwave power plants??
I did some back of the envelope calculations for this and it turns out that almost all life will eventually evolve to have reasonable protection against it. Except in Australia.
You'd have to stick it in a lagrange point 1.5M km away though since just in orbit is not true zero G.
Microwave energy transfer should work. That's what I like about the Helion fusion reactor design they don't use steam to power generators it's direct power no water or steam.
In Germany, we call this „Fernfusion“. It‘s actually working beautifully, and I‘m a happy customer.
That sounds hard to meter and charge for.
About 1 AU distance, right?
I reckon Earth would need to be around 93M miles from the fusion reactor.
Tbh it sounds like that cure is worse than the problem…
I think you just invented the solar system.
Patent troll level 10/10
We shall be as gods!
Let's do it!