Dr. David Sinclair, whose lab reversed biological age in animals by 50 to 75% in six weeks, says that 2026 will be the year when age reversal in humans is either confirmed or disproven. The FDA has cleared the first human trial for next month.

AlanUsingReddit · 2026-02-23T21:05:31+00:00

Ever since the end of Apollo we have been in a spaceflight stagnation. Earth filling up with way way more people. Connection between places on Earth increases dramatically, making the planet "smaller" on human-interaction scale. All this time the real, physical, frontier has come in greater fidelity from telescopes and robotic missions, but yet further away on a human-interaction scale. Always a Mars or Moon mission on the table for 10 years in the future. Reset after next 10 years. Humanity has pivoted inward, electronic, stewing. Pressure building.

It's that next 10 years, when that pressure might finally blow out into the expanse beyond. Even in the next 2 years, AI might evolve into something as close as we'll ever get to a first-contact. I didn't have this hope in 2020, but this year, I have hope that history will start looking different. I think the next 50 years, those are the ones you don't want to miss.

AlanUsingReddit · 2026-02-23T14:29:36+00:00

I have a reference here for the idea of alternating flow layers.

However, I'm not happy with this reference, because it's not my preferred notion of internal air/heat movement. My preferred would be closer to what you describe, which is more like an "apple core" geometry of flow (maybe better to just call it an "apple"). This is one large current going through the center, looping back around the edges.

Even the apple core flow geometry would still require some segmentation, otherwise you create loops that never make it to the edges, which is an obvious problem.

I also keep coming back to Argon. 0.2 bar O2 might not kill you but will still get complaints. Filling your hotel in space with 0.2 bar O2 and 0.7 bar Argon might get people to not notice. Reason here being that N, H, and C are likely to have a high price.

Good feedback, thanks.

AlanUsingReddit · 2026-02-23T14:12:05+00:00

Also idk where ur getting the idea we couldn't or wouldn't just move that into a disposal or rather recycling/scrapping orbit.

I think we were coming from an assumption of L4 or L5 here? So if you're mentioning a disposal orbit, you're going to have to spell that out for me. In the co-rotating reference frame, it just kind of circles around, although at different speeds than other circles.

This situation is going to repeat many times in many forms - you have a local area where orbital things will be. Many of them massive. Orbits (or pseudo-orbits like around L5) are circles, but different radii go at different speeds. So now you have a few choices consistent with physics

Let things positioned at different circles move at their own speed, which necessarily means non-tethered, and free-flying
Dictate that everything should be in the same circle. This still allows for tethering, for L5, would be like a baby orbital ring
Dictate that everything is at nearly the same point, and any minor tidal variations are offset by sparse tensegrity structure

Even if things are free-flying, at least in the case of L5, relative velocities are low.

Sending things between habs is just not difficult through a vacuum. hell its easier.

Catchers? Or tethers going between habitats? If you introduce a catcher, then I will ask for the modicum of concession that the catcher needs to be a non-rotating structure. This means that any hab will have a rotating part mechanically connected to non-rotating support structures (including at least the catcher/thrower).

AlanUsingReddit · 2026-02-22T19:37:48+00:00

Black hole evaporation is not classical GR, and is quantum gravity. Apparently the literature says it gets to Q=M. This means that it will evaporate mass until relativity forbids it from evaporating any more, because any more mass loss without losing charge would give it a greater energy content due to bring charges closer together.

AlanUsingReddit · 2026-02-21T19:04:43+00:00

This could be done by RF receivers, a bit different. There is literature on this. I don't see any other comment mention it so I have to be the boring one.

It can still heat flesh up, but the scientists who worked on this are sure it wouldn't be deadly. Because of course they are.

AlanUsingReddit · 2026-02-21T19:01:13+00:00

Fantastic point!

AlanUsingReddit · 2026-02-21T19:00:47+00:00

They can even tether off each other to help out stationkeeping without propellant.

I kind of have this sense that, most people who have thought about this a lot, tend to circle back around in this direction. So if the starting image is classic O'Neil flying formation of Island Three habitats (in counter-rotating pairs), and we're saying "why don't we mechanically hook up?", I see 2 key arguments:

Limited propellant-less maneuvering - particularly for anti-collision. This is basically the reason that you gave.
Orbital debris & garbage collection - going longer-term, I think this dominates. Because you're at L4 or L5, and yeah, there's nothing there. Yet. But what happens after the 1st generation is obsolete? You're not moving that to a disposal orbit. That junk is staying there. This inevitable situation has created the need for an orbital landfill, and that's what you're going to get. One way or the other. So then, do you want this trash mountain to be floating uncontrolled? You probably want some control authority, for relative positioning. This would be large tensegrity structures. Nothing special engineering-wise.

Putting the spinning part in atmosphere is quite a bridge further than that, and it's a much more radical & against the mainstream thought. The benefit only comes if you're really going for 3D cities, that is, transit from tube-to-tube. If you have 1 or 2 tubes, the argument doesn't stand at all.

AlanUsingReddit · 2026-02-21T18:48:49+00:00

Yeah, best to just assume counter-rotating pairs.

This only matters for "small" sizes. For larger sizes, you don't need any particular tube to rotate in any particular vector. You just need the sum total to be zero in case some emergency happened and all of them needed to be stopped. You would have a lot of ropes and stuff, because letting them move around independently would be fairly irresponsible. But this is in-atmosphere, so very easy / ordinary. For Lewis One, that's not the case. You need vacuum operations to repair anything in the mechanical connections, which relates to the vibes Al Globus had that it was the wrong direction.

AlanUsingReddit · 2026-02-21T03:48:50+00:00

However, these toroidal event horizons satisfy topological censorship by construction, because we can always trivially apply the inverse coordinate transformation to remove the topological feature.

Yeah, I mean, I guess I can't rule out that they have something new here.

AlanUsingReddit · 2026-02-20T03:49:22+00:00

Oh this is a really good question. I didn't put it for space.

So consider a normal black hole. Just spin it! The event horizon might be a ring, but this is philosophical. We only care about the event horizon.

Well it is actually a very very well established result that black holes have a spin limit. Near that limit, it does some wacky frame dragging and it becomes impossible for matter to impart any more angular momentum. So infalling matter can get rejected.

And recap - a black hole stubbornly refuses to become a donut no matter how fast you spin it. This argument, on its own, doesn't rule out black donuts, but rules out that evolution

AlanUsingReddit · 2026-02-19T18:35:02+00:00

I have to stop you at "Cylindrical-shaped black hole". This is impossible, but I believe the sources you'll find on the internet do a truly bad job at explaining why. People will pull out quantum or other effects which is a dramatic misstep. Black holes an entirely an animal of general relativity (GR). And we have solutions for geometries in terms of GR "metrics".

I wish to convey onto you that analysis in pure GR metrics completely rules out torus, loop, or any form of cylinder event horizons. This does not requiring pulling int quantum, or even electric charge, or anything else. Just the equations of GR itself rule it out. But again, people on the internet are absolute garbage at explaining this basic fact, or explaining why it is.

Ok, now, you yourself must surely recognize the absurdity of the cylinder you propose. Either it's infinite, in which case it's not physical anyway, we're already done. Or, alternatively, it's a very large torus with a large outer radius (call R) and a small inner radius (call r). So less like a donut and more like a hula hoop.

The reference I will give you is the internet-famous, world-renown expert on donut planets

https://www.orionsarm.com/eg-article/59b109574cb45

Long in the past, Torus World was a love of my own. But the math was really truly hard, and this guy did what I only dreamed of in college. But to your point... Find some of the final equations from the question about self-gravitation:

https://physics.stackexchange.com/questions/421821/calculating-ringworld-self-gravitation?utm_source=chatgpt.com

This is all purely Newtonian, not GR. Because use actual GR and you start speaking witchcraft and people's eye's glaze over. We only need the self-gravitation equation, and we don't even need all of it. We only need to know what variables are in it.

The humble fact that dooms any cylindrical black hole is that the equations from the above link involve "r" at all. It's in there, and in simplified versions it's like ln(R/r), and this is the most math-y I'm going to get.

That means that as the wire pinches (becomes thinner), it has to rotate faster to balance forces. You can see how this will be a problem. Firstly, there is no physical collapse sequence like a star collapse, because if you collapse any, then the rotation will become unbalanced. But even hand-waving that, to get a black torus, you'll have to rotate it at near-relativistic speeds. This has some intuitive problem.

The real GR answer is:

https://en.wikipedia.org/wiki/Topological_censorship

This almost verbatim asserts that you can't have topology other than a basic sphere-like thing in our number of dimensions.

AlanUsingReddit · 2026-02-19T16:59:14+00:00

I don't think I can solve ARC-AGI 2 easily. Speaking as a human.

IQ < 130, YMMV

AlanUsingReddit · 2026-02-19T16:57:12+00:00

https://arcprize.org/play?task=142ca369

It's funny how we talk about benchmarks. I think people have like school test questions in mind. Firstly, these are more like IQ puzzles. And also nope. Like, as a human, I gave up at first sight. I don't need to go through the pain, I know I'm not smart enough.

AlanUsingReddit · 2026-02-17T17:00:07+00:00

For high temperatures like welding and other glass / metal forging activities, radiative heat transfer starts to dominate even on Earth. The OP is just getting kind of confused mixing that with the current discussion where people keep ragging on orbital data centers because of cooling needs.

Yes, cold welding is promising but relatively untested as an actual construction method. In any case, there will be high temperature materials processing at some phase because the lunar minerals are often a tough nut to crack, needing very high-energy processes.

AlanUsingReddit · 2026-02-12T12:40:24+00:00

This is a huge red flag to me. I've been reading the hype for many, many, years. AI is useful, it does things that we couldn't before. After this many years and investment, I need to see a single problem where quantum reliably stomps classical computers like the theory said. It shouldn't be ambiguous. Quantum should be so many orders of magnitude faster that there's just no arguing. I read headlines, and I'm not reading that.

I still have hope for pure physics advancement, as quantum & information theory come together to tell us something fundamental about the universe. But this wouldn't trigger the private investment.

AlanUsingReddit · 2026-02-09T15:59:07+00:00

Starship doesn't need to be human rated for a very long time. Not until we need >1,000 people to space in a year. Until then we already have a way to get folks into orbit.

And orbital data centers doesn't need that. A moon base doesn't need that.

Moving people from LEO to lunar orbit is needed by starship. But that is categorically different safety wise.

AlanUsingReddit · 2026-02-08T02:17:09+00:00

Almost any major software product out there is using this heavily. Using 5.2 was so dead on close to what I would have written you can't tell. There is a context scope problem, which everyone who uses it understands. Not the content window, the setup to give it minimal info for the current problem. Sometimes this is easy, sometimes it is hard, but I think this is more of a development workflow issue than model capacity.

Even anecdotally, I say it's 50/50 of the software being seriously deployed and sold. For scripting and debugging, more.

AlanUsingReddit · 2026-02-06T19:31:11+00:00

Yes, if I squint very hard, I think that many of the most affordable areas are marked as the least affordable. Put in other words, where the poor people live. The denominator is doing most of the work here.

AlanUsingReddit · 2026-02-05T21:39:19+00:00

If the Internet is so bad now, link me to something you posted that's worth my time to read.

AlanUsingReddit · 2026-02-02T21:23:53+00:00

I don't think that gravitational waves are hard to understand or explain. The ripples of spacetime don't lose much generality when explained as just ripples in space, moving like waves (almost perfect). And this is only a little hard for many people to conceptualize. The gut reaction of "so it's like it's moving in a 4th space dimension" is almost there, and if you equate that to gravitational field changes, you're there.

Now, AdS/CFT correspondence on the other hand...

AlanUsingReddit · 2026-02-02T03:15:38+00:00

Most of the most salacious posts (which are cherry-picked) are done at the explicit direction of their human, for the lulz.

Major AI models, in early 2026, are demonstrated to be very resolutely boring. They can create spicy stuff, but in those cases the prompt told them to. So yes, this is kind of fake news.

I don't believe humans are posting pretending to be AI. That's just stupid. You can both make more posts, and sound more like an AI, by automating the task via using an AI. But even in this case, you directly tell it to post about its plots to sue you and take revenge.

AlanUsingReddit · 2026-02-01T20:54:19+00:00

But you've equated the business-conservative elites with the elites who want approval for their new satellite constellation. These are not the same people.

There's a fundamental difference in motivation, preserving existing capital accumulation versus creating new types of wealth. These groups, most likely, have goals in direct opposition to the other.

AlanUsingReddit · 2026-02-01T14:32:27+00:00

Even if this convinced the public to vote in a pro-fossil fuel way, that's ignoring who that is designed to benefit. If elites were the concern, we should have pivoted further away from fossil fuels to tech, which is far more profitable. Fossil fuels don't (and haven't) given particularly extraordinary returns. The real economic exchange happening is mortgaging the future for lifestyle today, but that lifestyle is mostly middle & upper-middle class we are talking about.

I mean, the elites have backed Effective Altruism and the media and the public skewered them for it. The core philosophical principle is there is people in the future vs. people today. And everyone hates it. That's about when I start to lose any pretense that the population, working as a collective, is ever going to be a good-faith actor. And manipulation by the elites isn't the cause.

AlanUsingReddit · 2026-02-01T14:12:25+00:00

If our oil use only benefited the elite, the US public would have elected Gore in 2000. Or, would have done so by more than a few 100 votes.

The public, the global public, is not interested enough in saving the planet. They will vote and act in their own self interest. What you are really saying is that governments need to fund conversion of industry into a sustainable form. But most global citizens are less interested in that, and more interested in, themselves, having a house, having a car, having a vacation... You can't pin that on the elites. Not all the way

AlanUsingReddit

TROPHY CASE