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askscience

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BlueLineBae , in Is there any scientific study about where should the bed be facing?
@BlueLineBae@midwest.social avatar

The only real effects that I know of are light related. If you’re trying to sleep, making it as dark as possible is best. So using an eye cover or blackout curtains can help. But when you want to wake up, sunlight helps us wake up easier. This can be tricky in the winter when the sun rises later and doesn’t peek into your window until after you’ve already had to wake up. I think there are some phone alarms that will slowly add a warm light to the room to help with this, but I couldn’t say if they actually work or not. Hope this helps.

MrJameGumb ,
@MrJameGumb@lemmy.world avatar

I got some Cync adjustable light bulbs and I set them up in the app on my phone to turn on low and slowly get brighter when I need to wake up

neptune , in Could non-Newtonian fluids be used in the future as a kind of percussive ear protection?

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.

CanadaPlus , (edited )

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.

MrJameGumb , in Is there any scientific study about where should the bed be facing?
@MrJameGumb@lemmy.world avatar

I don’t think it really makes a difference unless you’re really into feng shui. The best position for your bed is whichever one allows you to sleep most comfortably

fine_sandy_bottom ,

My mrs claims to be into “feng shui”.

Honestly most of it is just sensible layout advice wrapped in bullshit woo woo.

DirigibleProtein ,

I’d drop a link to the Penn and Teller: Bullshit episode about Feng Shui, but I can’t find one.

BaalInvoker , in Is there any scientific study about where should the bed be facing?

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.

dustyData ,

only to sleep or sex

Don’t do anything exciting

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?

BaalInvoker ,

Oh, man… Don’t be like that…

You got what I said.

SatansMaggotyCumFart ,

I use my bed for pooping.

moody ,

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.

lemming ,

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.

lemming ,

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.

Brokkr , in Could non-Newtonian fluids be used in the future as a kind of percussive ear protection?

From some quick searches (so not a definitive answer, but a place to start), it seems that sound waves are most likely longitudinal which doesn’t cause shear. However, shear forces can be created by sound waves when they hit a surface.

From that information, I don’t think the shear energy imparted by a sound wave is very large. Since non-newtonian fluids only thicken under shear, they may not actually behave very differently than a regular fluid in these conditions. Preventing sound waves from traveling is usually accomplished by causing lots of scattering (open cell foam) or by absorbing the energy in a viscoelastic material (usually polymers).

JoMomma , in Could non-Newtonian fluids be used in the future as a kind of percussive ear protection?

Not that any of that would work, but just as a thought experiment: under sudden sonic pressure the fluid would become more crystaline and would then actually make the sounds travel with less resistance, so maybe that would actually make it worse?

h3ndrik , in Could non-Newtonian fluids be used in the future as a kind of percussive ear protection?

I think a fluid that you put in your ear muffles everything and makes it hard to hear. Being newtonion or non-newtinion. I can’t imagine a way for it to be useful as a general solution. You’d need to take it out anyways in order to hear normally. And then I don’t know how this would compare to an already existing high quality hearing protection. There are some available that supposedly are somewhat linear in the frequency spectrum.

smuuthbrane , in Could non-Newtonian fluids be used in the future as a kind of percussive ear protection?
@smuuthbrane@sh.itjust.works avatar

“Sudden” doesn’t matter. “Loud” does.

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.

CorrodedCranium OP ,
@CorrodedCranium@leminal.space avatar

Thanks I think this was the answer I was looking for.

CanadaPlus ,

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.

Also, shear-thinning fluid is a thing too.

Hamartiogonic ,
@Hamartiogonic@sopuli.xyz avatar

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.

smuuthbrane ,
@smuuthbrane@sh.itjust.works avatar

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.

Hamartiogonic ,
@Hamartiogonic@sopuli.xyz avatar

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.

ZephyrXero , in Why did groups of human beings migrate to northern zones of the world, and how did they survive?

I wonder if the Sahara turning into a desert could coincide with a mass migration. It used to be lush once upon a time we believe. But I can’t remember the timings of the two, so I’m purely speculating

agent_flounder ,
@agent_flounder@lemmy.world avatar

This article indicates the opposite, actually.

New research indicates that Homo erectus likely capitalized on a “greener” corridor through the Sahara Desert in northeastern Africa, which was wetter and more vegetated than it is today, during their migration out of Africa. Climate cycles aligned to create this green passage, facilitating their journey.

Apparently the desertification of the Sahara is cyclic.

Approximately every 20,000 years, the Sahara transforms into a savannah covered with lush grasses due to the angle of the Earth’s axis changing. This axis change causes the position of the North African monsoon to shift, a monsoon that could revive the Saharan region. (source)

Here’s a graphic on the timings of early human migration. They list two migrations northeast, one occurring 120k years ago and another 100-90k years ago.

https://upload.wikimedia.org/wikipedia/commons/7/73/Putative_migration_waves_out_of_Africa.png

ZephyrXero ,

Neat! Thanks

Treczoks , in Can humans reach near neutral buoyancy in a gas that is safe to breathe and contains adequate oxygen?

The problem would be that you would need a very heavy gas in that mixture. Which would soon unmix, with the heavy gas at the bottom and breathable gas at the top.

Also be careful with breathing even minute amounts of such heavy gasses, as they will accumulate at the lowest parts of the lungs.

I remember a TV show where they breathed such a heavy gas to show what it does to your voice (it transfomed it way down, just like helium transforms it up). They had to stay upside down after that for some time to get the stuff out again.

Lath , in Why did groups of human beings migrate to northern zones of the world, and how did they survive?

Same reasons we use today.

JackGreenEarth ,

Well that just kicks the can down the road, and is also probably not accurate. People move today for better jobs, to escape warzones, because they like a country’s laws, and more reasons. Most of those reasons didn’t apply to hunter gatherers living thousands of years ago.

Lath ,

Really? What if the better hunting grounds were taken? What if a rival tribe kept harassing another and people just didn't want to fight? What if the ambitious youth didn't agree with the tribal leaders, so they moved to make their own fortune?
At our core, we really haven't changed all that much from our ancestors.

WarmSoda ,

Could really be the same reasons for them too.
People moved for better hunting/grazing areas. To escape areas of warfare. They didn’t like the tribes rules, and more reasons.

givesomefucks , in Why did groups of human beings migrate to northern zones of the world, and how did they survive?

Pre agriculture you need a lot of land to support a small amount of humans.

It’s not like someone walked from Africa to Norway. A group would expand a little North, settle, then another group would move a little further north.

It was a slow gradual migration. So people slowly got used to the changes.

But like you said, the further North the less food, so they had to spread further and further each time.

officermike , in Can humans reach near neutral buoyancy in a gas that is safe to breathe and contains adequate oxygen?

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.

j4k3 OP ,
@j4k3@lemmy.world avatar

temperature/pressure/planetary gravity?

SkybreakerEngineer ,

Any combination of those sufficient to compress the gas to human density, will also kill the human

Also gravity affects both equally

j4k3 OP ,
@j4k3@lemmy.world avatar

What is the difference of a gas and a liquid here? I am neutrally buoyant in a liquid and can normalize to pressure at depths, why not gas?

Tarquinn2049 , (edited )

Liquid is incompressible.

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.

Rivalarrival ,

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.

pennomi ,

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!

Boddhisatva ,

It reminds me of Larry Niven’s The Integral Trees. It takes place in a gas torus of breathable air around a neutron star.

Asidonhopo , in How dark is Mars compared to Earth in a very practical sense?

I’m wondering if you’d be able to feel the warmth of the sun on your skin through a hypothetical martian window, probably only faintly.

neptune , in How dark is Mars compared to Earth in a very practical sense?

Mars is 1.52 AU from the sun, or 1.52x further than Earth, so the inverse square law says 43% less sun power. But the atmosphere is thinner and a different composition.

To know how the human eye actually operates on Mars, one would have to get a human eye to Mars.

j4k3 OP ,
@j4k3@lemmy.world avatar

Red rover, red rover, send a human eye over.

troyunrau ,
@troyunrau@lemmy.ca avatar

And, that eye would still need to be attached to a human. A living one. No shortcuts just launching the eye in a jar ;)

themeatbridge ,

Oh, man, you should have said something an hour ago. Now what am I going to do with these jars?

CarbonatedPastaSauce ,

And the other eye…

Zorque ,

What if we connect that eye to a neurolink?

troyunrau ,
@troyunrau@lemmy.ca avatar

Time delay would be super disorienting to livestream it into your ocular nerve or something… But sure!

Gork ,

It will quickly become festered with ads about where to buy a Cybertruck.

Pietson ,

I wonder if a human could even properly make sense of the difference after spending so long on a ship between the planets. Plenty of time to adjust

captainjaneway ,
@captainjaneway@lemmy.world avatar

Depends entirely on the ship’s lighting.

Pietson ,

I guess I meant more about how well you'd actually remember the brightness on earth after being on route so long rather than your eyes physically adjusting

j4k3 OP ,
@j4k3@lemmy.world avatar

This is more in line with what I was asking. The sun seems to have a psychological impact on humans. I wonder what that impact would be under both relentless cold conditions, but also when the sun never quite feels the same.

I mean, it is obviously subjective and not critical to the functioning of life or anything like that, but it just seems like one of those very subtle “death by a thousand cuts” kinds of elements that might become noticeable over time.

I don’t think anyone would directly perceive the effects in a binary logic kind of way. It would be like times when our local region is covered in thin high atmospheric clouds for weeks on end. It becomes more noticeable over time that this amount of light is not normal. I wonder about that awareness of “this is not normal” having more long term impact on psychology, not profound impacts, just some impact. I thought maybe someone had already posted images somewhere on the interwebs exploring this, but haven’t found any.

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