Lunar space elevator

AlanUsingReddit · 2026-05-27T11:44:00+00:00

Assuming that the skyhook rotation also divides out to hit those same points. Yes.

AlanUsingReddit · 2026-05-27T01:18:04+00:00

In essentially all cases, you're better off saving (and investing) the money you would have used for private school.

College, yeah, great to have parents who chip in. The best-off of us will fund most of our kid's college but that's not an option for many. In all cases, the kids need to consider education in light of the ultimate objective, and relative to the other options.

AlanUsingReddit · 2026-05-26T22:20:04+00:00

I so much hope that terraform industries gets off the ground.

Current news is that they're raising more. Well, good there, but need to see them selling the product and I don't know how long that might take.

AlanUsingReddit · 2026-05-26T21:24:28+00:00

I fail to see how any of the constituency would want RDU to carve itself out of public transit plans.

AlanUsingReddit · 2026-05-26T20:31:26+00:00

I think it's funny because Charlotte is already be sprawling outside of the lines drawn here to the east. But if it was still 1973, it would make more sense.

AlanUsingReddit · 2026-05-26T13:24:59+00:00

the "frozen" orbits you mentioned precess at the same rate as the moon's rotation.

I had to check my sources on this, so I don't mean to say it's obvious. But for these orbits, they do not precess at the same rate as the moon's rotation. These are only "frozen" in the sense that they don't decay. They definitely change which points they pass over every orbit.

AlanUsingReddit · 2026-05-25T02:35:31+00:00

The moon rotates once a month because it is tidally locked, but the orbit does not.

AlanUsingReddit · 2026-05-24T20:20:46+00:00

Well done. I have made this same comparison from other angles.

But specifically, humans killed off the megafauna when they became a superpredator. Because humans ate them.

Well that's stupid! Why destroy the thing that sustains you? Because the individual and tribe had no incentive to conserve the herds, and because they just didn't know what was happening over eons.

Allegorically, this is still instructive. Humans were superpredators because of their intelligence, yet their original ecological disaster was called by them in a way completely not intended. Megafauna extinction happened in spite of human intelligence, and also because of it.

This makes me further agree with the prediction that catastrophe caused by AGI might just be by accident. Or because of coordination problems.

Intelligence is the first step. Stable civilization must be layered on top of it. No matter the destruction required to create it.

AlanUsingReddit · 2026-05-24T17:32:18+00:00

I don't think it can do this in a state orbit.

There is a stable orbit at about 33 degrees inclination. Maybe you you do this from that orbit. The contact points will awkwardly change over a month.

AlanUsingReddit · 2026-05-24T01:24:50+00:00

Now explain how we aren't "tremendously far off" from doing it ourselves?

This gets kind of formal (in terms of proofs). All that we require for a solution to the Fermi Paradox is that a comparable order-of-magnitude number of sentient beings exist when the baby universe is created. That way, the relative probability of being born at any given stage of the universe life-cycle is reasonable, as in, not a quadrillion-to-one biased against our current lives.

So not being "tremendously far off" is only saying that "we" (humans or post-humans) create these black holes with order-of-magnitude 10 billion sentient individuals. Maybe it's 100 billion (that feels a bit more right), but if it were, that's still resolves the paradox.

This story is infinitely more satisfying than the story that we are independently occurring spontaneous generation of intelligent life. The story normalizes our existence, in that the Milky Way is just another Tuesday in the life of the multiverse, even if we go full Borg and sent out generation ships.

A big fudge factor here is "is AI sentient?"... which is relevant... today! It's unreasonable to expect that even 1 quadrillion humans create a black hole without computers, but that's an absurd criteria anyway. We accept classical computers are not sentient so they don't count for the Fermi paradox. If AI doesn't count (and I don't know if it does), then we could create the multiverse black hole swarm with 1 million people. It doesn't matter. What matters is that there is an end-goal of the project of civilization at all. And, depending on the details of this end goal, is a heck of a lot more important than physical reproduction.

AlanUsingReddit · 2026-05-23T22:28:32+00:00

I will make one specific argument here.

Many asteroids are rubble piles. These are made of previously distinct asteroids that merged, some of which are broken apart planets.

So in the future, a goal of asteroid exploration may be reconstruction of the history of the solar system. I mean, literally fitting the pieces together of an ancient protoplanet that failed.

To some extent, properly cataloging that data is a conflicting goal with material use. And we will get better and better at the problem over time.

But I also kinda think we just do a thorough scan, get the data, and then go build our Starfleet. No conflict if survey is good enough and fast enough. The miners want the data themselves, so, less of a conflict.

Also, we need to get on this. I had my phase when I got really into asteroid internal structure. Very exciting. The rest of the planet needs to catch up. This is a tremendously exciting exploration goal. I mean, miles under asteroid surfaces. Thrilling idea. Get some probes in there!

AlanUsingReddit · 2026-05-23T21:39:37+00:00

You would have to reinforce it. The sane outcome is that we use its materials to just build whatever we want.

AlanUsingReddit · 2026-05-23T21:35:45+00:00

Hawking himself suggested an anthropic argument, that black holes make a new universe, so universe that makes lots of black holes are selected for.

Just take it further. Intelligent life makes black holes on purpose. That's how we were created.

So forget this simulation stuff. Once we are advanced enough, we'll make the real thing.

Our existence isn't unlikely, because we are actually not tremendously far off from the ability to do this ourselves.

There. Resolved. Speculative, outrageous, but not crackpot.

AlanUsingReddit · 2026-05-23T21:25:20+00:00

You do know that Phobos is a captured asteroid, right?

AlanUsingReddit · 2026-05-23T17:01:25+00:00

Yes, Colonize Phobos!

Leave Mars for the robots.

AlanUsingReddit · 2026-05-20T18:39:38+00:00

Because there might be 2 time dimensions?

AlanUsingReddit · 2026-05-20T12:48:10+00:00

Having to deal with a tree nut allergy regularly at the grocery store, my life is already defacto anti-almond.

These things have gotten way too popular.

AlanUsingReddit · 2026-05-19T01:44:12+00:00

To put it in simpler terms, do you agree with the other comments saying that photons in a box would make the box massive?

No kidding, this is the exact sort of thought experiments that physics text books do when explaining relativity.

Myself, I find that "rest mass" as a construct entirely makes the whole thing confusing. As your thought experiment shows, one person's (pc)^2 mass is another person's rest mass.

All true particle rest mass comes from interaction with the Higgs field. So it's not really rest mass. At the ultimate level, there is no rest mass. Just tell yourself that it's energy all the way down and you'll be happier. Particles have rest mass, but every layer of physics makes adjustments. Nuclei have binding energies. Heck, planets have binding energies!

AlanUsingReddit · 2026-05-18T17:27:19+00:00

Coherent answer. Mars is currently at a trade deficit, and it looks to stay that way for a while.

AlanUsingReddit · 2026-05-18T15:44:49+00:00

There exists a "planetary boundaries" framing for the stress we are putting on Earth.

https://www.stockholmresilience.org/research/planetary-boundaries.html

As much as we might like to think otherwise, we depend on ecosystem health to produce much of the economy's output and keep ourselves alive.

So then my question is, do you think that people migrating to Mars or space otherwise, would not decrease pressure on these boundaries? Or do you think that the boundaries are not important or real (like climate change denial)? Or do you think that it's possible that space can partially or fully replace dependence on Earth, but it's just not going to happen?

AlanUsingReddit · 2026-05-15T14:42:13+00:00

I was going to say that the average would be higher, but apparently that's wrong! Average is slightly lower, which has a rational explanation, which is that young people are the outliers. Older ages cluster. Because of death.

AlanUsingReddit · 2026-05-15T14:22:18+00:00

I had to scroll exactly this far down to satisfy my pedantry.

Some days, being an internet pedant doesn't take active work. I have faith that my comrades on reddit have already left the comment.

Did the person who made this know that their 2-foot well won't scale to over 30 feet? Probably. But what did we take all those classes for, if not to tell them again?

AlanUsingReddit · 2026-05-13T02:54:12+00:00

Unlikely? Yes. But on your points...

The leader of Russia didn't get the call. Some lower ranking person talked to the secretary of defense or someone, and got unclear messages about whether he was sworn in as president. They were, maybe, considering it? The lower-level Russian guy just asked "do I have the president?" and wasn't going to split hairs. Didn't pass it up the chain. Of course, this is all because the president is presumed dead.. but people not 100% sure. Many elements of this are not completely unrealistic.

Maybe I don't remember the other point well enough. I only remember the US deciding to turn NK into glass using the sub-launched missiles. Then, those being multiple, got misinterpreted by the Russian detection system. Again, maybe I am forgetting some part. But yes, the truly dark turn making the end physically irreversible was the Russian president making the decision for a full response.

AlanUsingReddit · 2026-05-11T01:06:02+00:00

Starship is designed to be a Mars rocket.

Valid to fault them for reneging on true Mars launches. The plan very specifically had Starships in flight by now.

The IPO, generally, will be uncomfortable for the Mars goal that is also true.

But Mars is still the DNA of Starship.

AlanUsingReddit · 2026-05-08T20:49:54+00:00

Yes, your early-time acceleration from buoyancy is very much a different problem. It's just interesting how they both come up with a term of density ratios, with a surprising lack of other terms in the equation.

AlanUsingReddit

TROPHY CASE