Like the post! I was wondering along similar lines myself, although wrt surface area of Moon and planets rather than Sun energy output. I wonder if the concept of staking (analogous to crypto staking) would be useful here? Where instead of "renting" it to the highest bidder, you directly say - I want to invest my fraction of Sun output in e.g. the Alpha Centauri colony project, or Mars terraforming, or whatever.
The reasoning is as follows. Neither 10E-10 of Suns energy output nor a few acres on Mars are directly usable by an individual on Earth. And in case of Mars they are not really commercially very useful to anyone at all, at least not for a long long time probably even after we have space industry. In case of Sun energy, 10E-10 of it is just such a huge amount that if used for personal consumption it would create a life of absurd luxury and hedonism beyond any reason.
On the other hand, both of those things are extremely useful for the kind of very long-term projects that we envision to build out the Solar system to its full potential - terraforming, continent-sized space habitats, giant power collectors and transmitters, large-scale interplanetary transport, that sort of thing. So the idea is - why not skip the middle part where such a project needs to come up with a way to monetize or fund what they are doing to pay people for their fraction of the resource, and instead allow people to directly choose which project to support? Especially since these resources are not practically useful to people anyway until after a number of such projects are completed! And you incentivize people to spend their "cosmic endowment" building something great, instead of trying to come up with ways to spend it hedonistically.
Of course you loose the numerous advantages of market economy with this approach. But realistically, with astronomical-scale UBI, the economy is not very market-based anyway. And at this point the operations are probably mostly run by the AGI(s), in which case capitalism, or at least human-based capitalism, is probably completely out the window. Another issue is that plots of Mars are not as interchangeable, but that you can easily solve with some market for leasing the plots acting between different projects.
Epistemic status: A concretizing sketch exploring a vague idea.
A recent podcast[1] floated the idea of legally entitling everyone to the proceeds of a fraction of the Sun. Here are my early thoughts on how that might work.
The idea is that, many decades or centuries from now, a majority of economic activity might be powered by spacecraft orbiting the Sun. This is certainly where most of the energy in our solar system is. And it might be difficult for a human to make a living in this high-powered economy (let's say), so perhaps we should arrange a state-like entity to pay us all a basic income based on this natural resource, like a more lucrative version of the oil UBI in Alaska. (This plan might be assuming a unified human government, which would be a whole other challenge.)
The first downside that occurs to me is that, in the current early days of solar, it's counterproductive for everyone if we introduce legal obstacles. From the perspective of 2026, if one company managed to start collecting 1% or 10% of the Sun's unused light, that would be amazing! Whatever they're selling is going to get incredibly cheap. Only much later, when the Sun is surrounded by very very many spacecraft (with a gap pointed at Earth), will that 10% become a problem. So perhaps this plan would be net-negative for most humans until space is far more developed.
In any case, how would we even define a fraction of the Sun? I can't exactly build a house on a plot of land there. Let's instead say i own 1 / 9 billion of the Sun's energy output (wattage). If i own solar panels with total power collection less than my entitlement, this is legal & great. Once i own more, however, i have to start renting the extra sunlight. (If i don't, various future law enforcement systems will harass me.)
So let's say there's a central database (or distributed, whatever) where everyone can set the price for their slice of sunlight.
'I think i'm going to raise the price on my sunslice this month,' i comment to my friend, 'but i feel a little silly charging rent on my sunlight when i'm sitting here getting a tan like i don't even value the stuff.'
'Well, you know what they say: If you're enjoying the sunshine, that is using it.'
Let's say the state automatically matches you (the solar panel owner) with the lowest-priced unclaimed sunslice & sends you a email. 'Pay $283 within 30 Earthdays or you will be in violation.' (All market changes can have a 30 Earthday grace period because negotiations between Uranus & Neptune might take a while.) Your $283 gets sent along to whichever sunslice owner you got matched with.
The scheme strikes me as more inherently transparent than land-value tax, because solar panels are difficult to hide. The only fraud i've thought of so far is putting hoops & lines on your solar farm & claiming it's a large quantity of basketball courts.
(Of course, this scheme is subject to the usual obstacles with far-future democracy & extreme population growth. What if brains of simulated neurons have legal personhood ('cellless people'?) & one such person manipulates the market by buying lots of compute, running 1 million copies of themself, doing shenanigans with the new smaller sunslices, & then archiving all but 1 copy?)
An additional wrinkle: Are you allowed to rent your sunslice to a specific business partner, or only to the anonymous 'next buyer'? If you can negotiate with the entity of your choice, solar power companies may be incentivized to make discounted sunslice deals a condition of their employee hiring contracts.
But i suppose there is one upside to this scheme, even in the early days of solar power. Analogously to income tax, it's bad that it slows down clean energy, but it's good that it incentivizes everyone to support clean energy. I don't know if that incentive would survive contact with irrational political rhetoric - 'Even tho you hate the greedy space-solar billionaire who runs the world's biggest corporation, look on the bright side! They're bribing you.' - but it's something.
The scheme i've outlined, of course, has no particular protection for the sunlight pointed at Earth (or other planets). So perhaps additional laws should charge heavy fees for obstructing the sunlight of a inhabited body. Similarly, some thought should be put into when it is permissible to collect light from one of the Sun's tighter orbits, thus casting shadows onto other heliocentric spacecraft.
And of course, splitting the Sun leaves the Centauri stars unregulated, incentivizing activity there. This is probably good. Once humanity is self-sufficient enough to hop stars, we will be much more resilient against extinction.
What i like about this entitlement scheme is that it forces alignment between humanity & the economy in a broadly sane way. But i think it won't be very useful in this century.
I think it was probably Will MacAskill on the Win-Win podcast on 2026 Jan 27.