It probably wouldn’t make any difference in the appearance of the belly button, because eventually it work dry up and fall off, just like if you were to clamp and cut it. There are definite benefits to delaying the clamping of the cord. There is a lot of blood in the cord and placenta that is lost that could be auto transfused to the baby if the cord is left intact.
The main problem with leaving the cord and placenta intact is that there is a risk for infection or blood loss. Also it would look really gross in the baby pictures.
David Sinclair is an interesting person. I’ve seen him present his research in a professional setting and he does some really interesting science. He is also very enthusiastic at selling his story.
There’s likely no amount of supplement and drug cocktails that will undo the damage of a sedentary lifestyle and poor diet. Best case scenario is this research could be on to something that significantly augments a healthy lifestyle, or worse case it could be wasting a lot of money on something that potentially ends up being harmful a few decades from now.
I’ve looked at the list of supplements and drugs Dr. Sinclair takes and there is mechanistic rationale from cell culture and animal experiments behind the ones I’m most familiar with. But it is a big leap to go from cell culture and animal models to human health on a much longer time span. The clinical trials needed to really demonstrate a lot of these claims are incredibly expensive and would take decades. Drug companies in the anti-aging field tend to focus on older patients to start with and earlier endpoints like lower cancer, Alzheimer’s, or heart disease incidence. They also tend to be funded by silicon valley tech executives.
The cheapest materials would be what can be acquired in space without having to launch from Earth. As a result, you're going to want to build your O'Neill cylinder out of some combination of iron, aluminum, titanium, and silicon dioxide.
The last of which might be particularly useful, as it is the main ingredient of fiberglass while also being the most common substance on Moon and asteroids. As a result, you probably want to build your cylinder primarily out of fiberglass. You can get pretty decently sized cylinders, as fiberglass has a higher strength-to-weight ratio than steel. Apparently, 24km diameter is a viable figure. Scale up length the same way, and you'll get 96km. So a 24km x 96km O'Neill cylinder made out of fiberglass.
That would be about 7238 km^2 of usable surface area. Half that to 3619 km^2 to make room for windows (as originally envisioned by O'Neill), and assuming a density comparable to New York City (about 11,300 people/km^2), you'll get around 40 million people. Or about the population of Tokyo.
That's seems plenty for any sensible space colonization strategy we might adopt in the future. And what's best is that you don't really need any fancy technology. Just use solar power to power mass drivers and deliver raw materials from the moon or asteroid via electricity. And it won't be any special materials either. Raw regolith can be made into fiberglass, so cost can be kept surprisingly low. The only question is scaling it all up, which may unfortunately be too expensive or will take a very long time to happen. Ultimately, this is still sci-fi, albeit on the hard side of it, since no fancy new technology is require.
I’d like to see a pressure vessel made of fibreglass that size… Not happening. Wall thickness in pressure vessels scales
Simple calculator, assuming steel… a 24 km diameter pressure vessel at 15psi is over 13 metres thick steel wall to contain the pressure. checalc.com/calc/vesselThick.html
Just the volume of steel required would be astronomical. You might be able to do this out of a similar mass of fibreglass… But forget launching it from Earth (would have to be made in situ).
And, largely, forget the fantasy renderings of what O’Neill cylinders look like – they are anything but lightweight.
This is sci-fi stuff. No one is seriously saying we could build this anytime soon. It will require a radical advancement in space travel capability. But the interesting part of this is that it doesn’t any new technology. It needs only the technology that we currently have, just scaled up massively.
As it is an O’Neill cylinder, the raw material needs will be truly huge. We’re literally building a city on the scale of Tokyo but in space. So we are just assuming that someday, we can move around that amount of stuff in space.
It’s far more than building a city the size of tokyo. It’s the mass required. If you weighed Tokyo, and then engineered a hypothetical Tokyo in space, you’d find that the mass of the equivalent materials would be orders of magnitude higher than even your worst estimates.
Back of the envelope, you put Tokyo in a cylinder with a similar surface area to actual tokyo, the volume of steel in the walls of the containing cylinder (just the pressure vessel) would be about … 60 billion cubic metres, or something like 450 billion metric tonnes of steel. As a point of comparison, tokyo tower is… 4000 tonnes.
As another point of comparison: our global annual steel production is currently around 2 billion metric tonnes per year. It would take 200+ years worth of global production to build just the pressure vessel for a tokyo in space. Unless you’re building this at your source of raw materials, it just doesn’t happen.
Yes, that's the point. It's far beyond the actual city of Tokyo in terms of construction difficulty and scale. But it doesn't need any new technologies to be invented to be doable. Just the ability to build on that scale.
But the point is if you get your materials from the Moon, for example, it’s vastly more economical to just build a Moon colony (or another Moon colony) than a space colony of the same size.
Then you'll have to deal with Lunar gravity, which may be unacceptable for long durations. Humans may have to live in giant space stations if we want to live in space. And since they can be truly massive, it may be more desirable than what some might think.
The ideal solution is probably not to build a colony in the middle of space, but rather find a celestial body with the necessary materials with gravity low enough to be acceptable.
Moon gravity too strong? Try smaller moons. Phobos? Europa? Charon?
First, you’ve got to realize that you’re making several very bold assumptions given current physics: (1) that we can build O’Neill cylinders with current or future materials that resemble anything like sci fi expects (probably not – pressure vessels are hard, mkay). (2) that we have a means to accelerate something larger than a probe to a significant fraction of light speed (this is actually the least difficult problem, but I suggest you look at the energy and travel time requirements). (3) that there’s any conceivable way for this thing to stop upon arrival (much harder problem without magic engines).
If all of the above are reasonable, then, well, you bootstrap manufacturing in situ in the asteroid belt or in a planetary ring or whatever. Not a huge problem. You obviously need to target a second or third generation solar system in order to find metals and heavier elements on arrival, but that’s trivial if you’ve solved the “stopping upon arrival using the energy and mass you brought with you” problem.
If you could send very small self replicating factories that could take their time to arrive, and upon arrival built a huge laser array used to slow down your larger shipments as they were inbound, you might be able to pull it off… With a few thousand years of preplanning. ;)
I agree with nearly all of your points. The stopping problem is the same as the accelerating problem. Assuming near infinite energy reserves, but limited power generation, then the ship would accelerate for half the trip, turn around, and then decelerate for the 2nd half. Depending on the amount of power that can be generated, earth gravity may be possible during the trip (except for the turn around in the middle).
The accelation problem is easier because you can build massive infrastructure in your home system that doesn’t need to make the journey, so it doesn’t incur the tyranny of the rocket equation. Still need massive infrastructure and huge amounts of energy, but it’s much easier to imagine a dyson swarm of lasers firing at the mirror at the back of the spaceship. :)
There’s no reason that we would expand out at the speed of light in one direction. It’s well within the realm of possibility that we can intercept rogue planets or large asteroids to use as long time habitats. Also we can expand in millions of directions at once at sub-light speed. The journey make take a million years, but we’ll reach a million places at once.
I didn’t say speed of light – just a significant fraction of it. Even 1% is extremely ambitious from an energy budget perspective. 10% or higher is probably achievable for small outbound probes using laser based acceleration – but they’ll just cruise by systems without any means to stop. For large “settlement” ships or similar, even getting 1% would be colossal amounts of energy (like percentages of the sun’s total output). So, yes, you’ll need to take the slow road.
Rogue planets come within a few light years of Earth. We could probably have a low speed, multi-generational ship to intercept one in a few hundred years. Once we’re on we’re hopefully good forever. Likely we’ll come close enough to some other interstellar bodies we could populate as we travelled. Exponential growth is bound to take off.
Yeah, if we aren’t in a hurry, and we can set up some fusion reactors and such on them and build whole civilizations on these rogue planets in the dark, it would work. Depends on how early and often we set up shop on passing planets, but in theory we could colonize much of the galaxy in a few revolutions around the milky way. So, under a billion years. ;)
The materials have been shown and proven in theory. It is simply a matter of building the space based manufacturing and infrastructure required. This is like Romans talking about what it will take to build nuclear power plants if they could somehow imagine them. I laid out the economy scale that I am talking about at the outset. This is an order of magnitude, or more, larger total human economic output. An era when this construction scale is not very novel.
Assuming we are talking about an era when Sol has a thriving space industry and the Solar system is broadly colonized.
If we are colonizing the rest of the Solar system, we figured out large scale and pressure vessels already. Once we are building in space with materials sourced from space, most of the problems go away.
Worst case, a ship can use nuclear detonations to both accelerate and decelerate easily within the limits of known materials. This has been thoroughly researched in a US program that was only canned as part of anti nuclear proliferation act. This system can easily handle both ends and traveling faster than any current method. It is a worst case. If we can master fusion, there are other ways as well.
I said generation ships too. I don’t care if it is slow and I think humans could cope just fine on a large enough ship, assuming we don’t find ways to put humans on ice.
I highly recommend checking out Isaac Arthur’s content on YT as he goes though all of this kind of stuff in detail but even further into possibility and future tech. I’m getting much more specific into a time and constraints than what IA does in general.
we figured out large scale and pressure vessels already
No. This is an assumption not borne of physics or engineering. There is no magic material that will make large scale pressure vessels suddenly viable. It (and space elevators) are mathematical constructs, not real things.
Use this calculator. checalc.com/calc/vesselThick.html – punch in 15 psi for pressure, and 100F for temperature. Play with your pressure vessel. Wall thickness of large scale habitats will need to be many metres of solid steel (or equivalent material). Even if you magically mass produce carbon nanotubes or something, you still need hundreds of millions of tonnes of carbon to pull off any large scale vessel. Your talking about ingesting entire asteroids just for building materials. You don’t launch that shit on an interstellar journey.
The important facing questions are “where is my window facing” and “where is my bed facing in relation to the window and door”. Magnetism is irrelevant, as we are no migratory birds who can actually sense that field.
Although you’re practically right, we can technically actually sense magnetic fields. It’s incredibly weak and you have to drown out all other senses, but it’s possible.
Facing away from the door (I.e. having the door in the back) makes some people anxious, like people usually turn and face the door in an elevator. That’s why a hotel bed often faces the door.
The position relative to the window is a question of light.
situational awareness. humans instinctually need to feel safe. sleeping with your head right by the door gives you the least amount of reaction time/space to stave off invasion. inagine a rabbit sleeping with its nose out of a rabbit hole. in modern times with modern locks and security, its not a big consideration to be faie. but the instinct is there. people like headboards on beds for the same cavelike feelibg of protection. so yea head away from the door, bed not by the door. windows used to be avoided for being drafty or leaking light.
Why ship pieces instead of shipping manufacturing capability (nano 3D printing etc) and use resources at the end point? By then presumably we’ve got asteroid mining down, no?
I think it would likely be similar to engineering materials today. The highest performing materials are very difficult to manufacture and we are talking about pushing them near their limits. I think a lot of the substructure will be made in-situ, but I think the most stressed parts of the main structure will require the largest scales of manufacturing. Like Sam Zeloof made a chip fab in a garage, so why doesn’t he start producing the next Nvidia GPU. It is that kind of difference here. A lot can be done there, but nothing like what can be done on the cutting edge of what humans are capable of making at out largest and most advanced facilities.
This kind of thinking is just superstition. The earth magnetic field does NOT influence in any way your sleep.
This is just magical thinking distortion.
The bed must be only in a cozy and dark environment, not too warm nor too cold. Also, your bed room must be used only to sleep or sex. Don’t do any exciting or stressful activity on your bedroom.
Do you mean to say that sex isn’t exciting. Or are we only supposed to have boring sex in our bedrooms. Or are you implying that the only exciting sex happens outside the bedroom?
Sex is for procreation only. No fun or excitement allowed. It must be silent, and exclusively in the missionary position. Deviation from these rules is unacceptable.
That’s a strong claim you’ve got there. It seems humans do possess some amount of magnetoreception, there’s even a suggested mechanism. It might be jammed by certain radiofrequencies, although I don’t know if they are still in use. Some other mammals have been shown to sense magnetism too. Personally, when I’m in a bed, especially a new one, I feel my rotation relative to my normal bed. It isn’t very precise and it’s difficult to test, so I can’t be entirely sure, but that’s how it feels. I don’t know about any studies relating magnetism and sleep. I know there historically were people who claimed it matters to them, but I think that unless you already know that it matter to you, it probably doesn’t. I’d say that much more important is darkness. Also, I heard people feel better with feet towards the door, but I don’t know if it’s proven in any way.
I wonder why I’m being downvoted. I very much welcome discussion. If you want to tell me why I’m wrong, like that cryptochromes cannot be used in sensing magnetic field upon closer look etc., I’d be excited. Disagreement without pointing out any mistakes I did brings me nothing.
If it’s just disbelief, I would’ve preferred being asked for sources. Even wikipedia mentions some of what I wrote (en.m.wikipedia.org/wiki/Magnetoreception) and while I admit my source isn’t primary literature, it is a monography about senses and I would’ve made an effort to track down at least some of the original papers.
It’s toxic, but a useful reference point: tungsten hexafluoride is one of the densest known gases in existence. At a density of 13kg/m^3 at standard temperature and pressure, it is nearly two orders of magnitude shy of being dense enough to bring a human (~1000kg/m^3) to neutral buoyancy.
Compressing a gas to nearly 100x it’s natural density is going to dramatically increase it’s temperature. In simplified mechanics, you can basically think of it like all the energy that makes it the temperature it is naturally will still be there when it is 1% of it’s original size. So all that energy is “overlapping” and adding together to make it’s new temperature based on there being 100x as much energy in each place now. Even if it started at 10 degrees Kelvin, assuming a linear gain, it would be 1000 degrees Kelvin after compressing.
Of course all of that is super simplified and not the “real” math or mechanics in all their complexity. But it should help illustrate why it would not be possible or a good time.
And that is only the temperature half of it. Compressing an area to 100 atmospheres, which I’m presuming would be the level of pressure necessary to get that gas (or a safer slightly less dense one) to the needed density range, would also be pretty dangerous if not immediately fatal to the human. Again that level of pressure is assuming a linear gain, I don’t know for sure if it would be linear.
So even if you manage to find something you could breathe, you wouldn’t be able to at that level of pressure. You would need to be wearing a suit that can be pressurized and breathing from something that isn’t feeling that pressure. Which completely defeats the whole point of choosing a medium to be immersed in that doesn’t require a suit or tank like being in water does.
It is however, theoretically possible to breathe liquids. Just incredibly uncomfortable for humans. There are humans that have survived it in experiments. After an initial adjustment period where your brain is certain you are drowning for a few minutes, eventually you are able to over ride that when you don’t die. Then you can hang out for a bit not dying despite it seeming like you should be… and then when you are done breathing liquid, the terrible part starts, you have to get the remaining liquid out of your lungs so there is room to put air in them again. As much as the rest is not great, transitioning back to air was universally considered the worst part of the experiment.
You’re talking about adiabatic heating, which is where temperature changes due to change in pressure, without heat transfer. If we thermally isolate the gas as we compress it, the temperature will rise.
We don’t have to insulate it. We can allow the heat to transfer out of the gas as we compress it. Heatsinks on the pressure vessel will pass the heat from the pressurized gas into the ambient air until their temperatures equalize.
Since we can add or remove heat from the gas after it is compressed, the temperature of that gas is only relevant if it falls below the boiling or freezing curves, allowing the gas to condense into a liquid or solid.
You could likely fly using human power on Titan. It has a 50% denser atmosphere than earth as well as only 14% of the gravity. While that’s not neutrally buoyant, it is enough that if you had some big wings attached to your arms you could generate enough lift to fly by flapping. Comic by XKCD about this topic.
Of course, Titan is also insanely cold, so you’d need a pressure suit, which might throw off the calculation.
This also reminds me of a scene in Arthur C Clarke’s 3001: The Final Odyssey, a relatively less well known sequel to 2001. In this scene there are enormous space elevator towers that house humanity, and in the upper floors where there is low gravity they have a pressurized flight room just for the fun of it.
We have pressurized areas in microgravity today (space stations), which would obviously give you neutral buoyancy. Not a whole lot of room to maneuver around though!
I don’t know about scientific studies, but in my experience I sleep best when the mattress side of the bed is positioned towards the ceiling. Also, putting the bed in front of the door can be somewhat inconvenient, specially if the door opens inward. Other than that, everything else seems to mostly be fair game.
It’s safest to keep your bed against an interior wall instead of a window, in case of earthquakes or other natural disasters. Or even someone crashing their car into your house, bombs dropping, etc.
I don’t see how anything non-Newtonian would be better against sudden sounds. In fact it would be worse, as they’d get more solid and thereby transmit MORE of the noise you’re trying to block out. Or maybe they only get more rigid but their sound transmission properties don’t change at all. Either way, sounds somewhat pointless.
The only way I can think that something like this would work would be to have a molded vacuum chamber as an ear plug, with a specifically engineered sound transmission bridge inside. With too much energy trying to go through, it would break. But I doubt it would be quick enough to be effective, and they’d also be one time use, and extremely fragile.
It’s a bit oversimplified, actually. Sound bounces off of discontinuities in the medium, which is why foam works. You just have to control the scattering somehow.
The big problem with using oobleck or whatever is it responds to shear, and shear can’t travel through air. You could use it for earthquake protection, though, or if you could channel compressive waves from the air into shear form using a fancy bridge like in OP.
There are lots of strange options besides newtonian fluids. Would be interesting to see how dilatant, peusdoplastic, thixotropic etc react to sounds. Perhaps there is a way to make a material that allows quiet sounds to pass through and blocks all the loud ones. My guess is that dilatant liquids should be a good candidate.
A quick search tells me this have to do with shear forces. Sound would be entirely compressive, so those material properties would have no effect, or at least not change due to sound levels.
That’s unfortunate. Just like OP, I would have really liked the idea of using a non-newtonian fluid to filter out certain types of sounds without using electricity. Well, I guess, we’re back to active noise canceling then.
We already have computers that can determine which sounds to cancel out. That’s pretty cool.
Sound isn’t going to be like a bullet or an electrical storm hitting the grid. I don’t think you can just make a material that blocks out sound when it reaches a certain level and allow it below the threshold. Definitely an interesting theory but I am not sure how it would be designed.
Compression thickening/thinning, which only starts after a certain rate of change. I’m not sure what materials have such a property. Then, you’d incorporate it into a composite which dissipates sound selectively in one state. One idea is a fibers of a material that matches the impedance of the fluid during quiet periods, but scatters it as impedance shifts during high-energy periods.
Maybe you could use standard shear thickening somehow, but it would be a lot harder as sound only travels through air compressively.
askscience
Active
This magazine is from a federated server and may be incomplete. Browse more on the original instance.