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> If we are being reckless and just want to use power until we figure out nuclear fusion or something better, let's say a million years or so, we can make some 180 PW from tides. But since it would almost all turn to heat, and since that is more energy than the Earth gets from the Sun, that would probably be unwise unless we find a way to get it off-planet with very high efficiency.

I think you're touching on the problem very nicely here: the problem is not "how much raw energy is there" (because there's an absolute fuckton of it) but "when does the impact of capturing this energy - thus removing it from a complex ecosystem whose stability may depend on it - and turning it into something else - thus adding to a complex ecosystem in other ways - becomes a problem", which may or may not come well before the theoretical raw energy cap.



I'm not sure those considerations are applicable. There is no "ecosystem" that depends on the rate of slowdown of Earth's rotation - we do need to leave some rotation to keep flora and fauna alive, but that's a "reservoir" problem, to use the OP's formulation, not an intensity one.

As for the addition of energy (heat) to the planet, sure, but there's nothing specific about tidal energy here. All energy sources except solar (and wind/hydro which are direct solar derivatives) add heat to the planet that would otherwise have stayed sequestered. But it's many orders of magnitude less than the heating from solar energy, which is why increasing Earth's absorption factor by a few points is an infinitely bigger problem than all the energy we are directly producing or can hope to directly produce in the next few centuries.


Also worth noting that trying to extrapolate the effects of current technology at this timescale is pointless.

There will be tide changes in human’s technological capabilities long before there could be any reckoning for over-extraction of the Earth’s rotational energy.

For example, in our ability to bring mass into orbit. Add a couple orders of magnitude in that capability, and humans can start directly tuning the Earth’s total solar irradiance by shooting lunar dust into a Lagrange point, reducing the amount of sunlight hitting the Earth by fractions of a percentage.

The Lagrange point is not perfectly stable, so the dust naturally dissipates over a 10-20 year timescale. If you don’t keep sending more dust, the “planetary sun-shade” naturally dissipates, so there’s zero risk of overdoing it.

Basically, within the next ~50 years, I predict we will gain the ability to turn down the planet’s thermostat in a very safe and predictable fashion, without having to pollute our own stratosphere. Overheating the planet becomes a total non-issue.


How much dust would you need to shoot up to affect a statistically significant change in the amount of sunlight getting through?


A fuckton.

Roughly 100 million tons annually of lunar regolith launched into L1 by railgun.

https://journals.plos.org/climate/article?id=10.1371/journal...


:blink:

And this was being discussed credibly as "something we'll be doing in the near-term future?"


> within the next ~50 years

Very optimistic. We haven't even been to the moon again in 50 years.

500 years, maybe.


With all seriousness, I’ll throw in “the unexpected breakthroughs in intuitive AI will aid this effort.” I sincerely think that LLMs will at least make R&D cheaper.

Beyond that, “we haven’t been to the moon” isn’t a fair summary of our tech imo - a HUGE portion of that is political in origin, and private companies have invented reusable rockets which is pretty damn important


I sincerely think that LLMs will at least make R&D cheaper.

How, exactly? Because to me it's just as likely that LLMs will hallucinate alternative solutions based on their flawed world model which will send numerous unfortunate researchers on wild goose chases that turn out to be exactly that. And I expect the volume of impossible-yet-probable-sounding solutions will dwarf the actual costs saved by using an Automated Induction system.


Long story short: every engineer and scientist in the country will suddenly get 100 interns. Will they make perfect work? Hell no. But current levels of Intuitive Computing LLM tech can be extended to much higher levels of autonomous/agential behavior, and that’s all you need to bring computers from a tool to a partner.

Your criticism of an all-in-one induction system / Reasoning Engine is well founded, no disagreement from me. I just think that they’ll be able to help in myriad, smaller ways. Finding synergies, analyzing data, designing and employing frameworks/simulations/tools specific to the researcher’s work, and just generally being a bank of knowledge that can be easily browsed through complex linguistic filters.

IMO :) I am an optimist. Maybe it turns out chatgpt is the best we get, in which case I’m very very pessimistic about our chances of meaningfully solving climate change, rocket-launched-lunar-dust or no. So… I have a “fingers-crossed” based leap of faith in my reasoning somewhere


> There is no "ecosystem" that depends on the rate of slowdown of Earth's rotation

I mean, raise acidic/temperature levels only so slightly and it kills off coral reef, which in turn destroys fauna that depends on it, leaving huge areas barren.

What I'm getting at is that small changes can have dramatic domino effects. Mass-scale tide dampening could have unforeseen effects.

Not saying any of the solutions are going to be a problem, merely that it's better to ask crazy questions about what happens when they ramp up at scale than handwave things away with uniform spherical cows.




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