How side-by-side are we talking? If the antennas are closer than their size, yeah, it won't necessarily work the same way because they'll act like one antenna. If they're too far apart for "near field" effects (or if your antenna was tiny relative to the wave to start with, like with AM radio) it won't matter, because the wave in question will just kind of ooze around any obstruction, and received power will just go with inverse square of distance to source again.
In practice, it's unlikely to matter so much how loud the signal is, because (unless you're using a crystal radio) you are definitely going to amplify it quite a lot before it's useful, anyway. More of concern is how loud it is relative to any random noise that's present, which is not so dependent on antenna area.
Edit: I suppose if it's between you and the source, it will dim the signal a tiny, tiny little bit. Not the way a bigger thing can cast a shadow, though; think more like a slightly dirty lens.
Yup. It's typically amplified quite a lot in the receiver, and the vast majority of power transmitted never is received, so it doesn't usually matter, but it's not a dumb question.
The current produced in the antenna does (induce a field which goes on to) cancel the wave out a bit. Not enough to be noticeable in the far field, for a normal-sized antenna, but some. Conservation of energy, right?
Yep. It's called near field and far field in radio. In the far field you can approximate it as a beam from the transmitter, while in near field it's magnets and things can absolutely interact. You never want to put up a stand-alone antenna in the near field of something conductive. Those big tower antennas actually incorporate the ground as a critical part of their design, because of that and the non-negligible conductivity of ground water.
I know evolution is governed by chance and it is random but does it make sense to "ruin" sleep if there's light? I mean normally, outside, you never have pure darkness, there are the moon and stars even at night. In certain zones of the Earth we also have long periods of no sunshine and long periods of only sunshine....
but even in the absolute middle of nowhere with no artificial lights, you’re going to be able to see fairly well.
I'm not sure I'd say fairly well. Maybe always well enough to not walk directly into a tree in otherwise open terrain. A full moon will be comfortable to walk around in, but new moons happen just as often, and sometimes the moon is below the horizon.
Source: Have walked around in the country at night.
We're diurnal, and have eyes optimised to see maximum colour and detail instead of well in dim light (at least by mammal standards). It makes sense we'd gravitate to fairly dark conditions to sleep, because while nature at night is not perfectly unlit, it's still pretty dark. Darker than a developed-world urban area will ever get, for example.
That being said, many people are completely capable of sleeping in a bright area, myself included.
As for the bonus question, yes, the hormones at least work backwards in nocturnal animals. Melatonin wakes something like a shrew up.
Hmm. Are we talking a high canopy, and fairly level ground? I feel like I'd definitely break an ankle if I tried sprinting otherwise.
I never had too much trouble, but sometimes things hiding in tall grass would surprise me, and in heavily treed patches I'd occasionally hit a low branch I didn't notice.
I also have to account for the fact that there was some light pollution, and I could always see skyglow from towns in the distance. I doubt land ever gets close, prehistoric or not, but in the darkest conditions that happen at sea apparently you can't see your own hands.
I could nitpick some of the details there, but instead maybe I'll just ask what point you're trying to make? A healthy human can still pick out something small way better than a goat.
Optimised just means designed for something at the expense of other parameters. We lost our tepetum lucidum at some point in evolution, probably for the 3x-ish resolution gain, while becoming much more shit in lowlight in the process. That's a tradeoff, but a good one for a tree-based diurnal frugivore.
Cats (for example) still have theirs, which means light as two chances to hit their retina, but means there's an upper limit on how clear an image can be, exactly because there's light bouncing around. It sounds like 20/100 is typical for them, from a quick search. Cats are traditionally thought to be dichromats, as well.
Yeah, we played paintball even, but stopped because one guy ran straight off like a 6 foot mini cliff. A couple of us were chasing him and he just disappeared. Was freaky as shit like that scene from LotRs.
Lol, yup, that sounds right. I did that once, although it was only like 3 or 4 feet, and I didn't like it one bit. Is was a sinkhole or something too, because it was cliff all around, and I had to find a spot to climb out. I didn't visit that area again.
I forget where I heard about the sailing thing now. That would be a 1 on the Bortle dark sky scale, though.
We actually have less genetic variation than most animals. There was a lot of bottlenecking in the paleolithic. And what little we do have is still mostly confined to Africa, because the rest or the world shared common ancestry as we left our original continent.
Like, 1 in 200 people is colourblind, or something? I don't think that's a reasonable argument that we're not trichromats.
I mean, if you can create a vacuum, water at any temperature will boil-freeze. And the ice will sublimate afterwards above cryogenic temperatures, but I’m not sure how fast.
Even if you don’t mix the steam with the water, heat will seep in through the surface. At thousands of degrees you bet that water is gone fast - explosively - as long it’s not super deep. If this is for drying something, you can add a bunch of other hot inert gasses to dilute or push it out after, so when you cool everything back down it doesn’t re-condense.
If you have to add liquid water, it might be impossible, although I can’t say for sure there isn’t some weird non-linear evaporation effect that allows it to technically work on very cold water. Intuitively, you are always adding more additional water than additional heat, but water is crazy and breaks usual rules for matter fairly often. I’ll do a bit of digging and edit.
Edit: Research turned up nothing. As far as I can tell, water evaporation is calculated as being a linear rate. Like the light thing someone else posted, that doesn’t necessarily mean there isn’t a counterexample, just that it hasn’t been found and publicised well enough for a quick search around. So yeah, no wetting away a puddle.
Well, genes, if we want to get really technical. Otherwise you can find counterexamples where genes are detrimental to the organism, but manage to spread anyway do to some quirk.
Depends how you’re using “why”. In Russian, they actually have two words for why, one of which implies teleology, and one which doesn’t, and merely requests some explanation for a phenomenon. I wish we had that in English.
In this case, it’s such a general question you can’t do much better, but you could, for example, talk about why oxygen-carrying proteins pretty much always incorporate an ion of something, in a merely cause-and-effect way. (And I actually don’t know the answer to that one)
Ah, so you haven’t heard about this thing. It’s not really lucky 10,000 territory, but it’s still cool.
There are situations, where in sexually reproducing organisms, an unambiguously bad gene can spread through the population, just by ensuring it’s more likely to appear in the next generation. As long as it’s not so bad it kills the species off, you’re still likely to observe it a lot in a future population. We’ve actually harnessed this idea technologically, with genetically modified mosquitoes that crash their local population by skewing all offspring malewards.
Well, you would know a lot better. And thanks for the reading recommendation.
What are your thoughts on viruses as a form of life? Asking what natural selection is in exact terms is pretty closely related to asking what life is, since life is probably some subset of things that can do natural selection.
A few fields are a bit like that. I remember my chemistry teacher in high school saying something similar.
As mostly a math person, it kind of bugs me. There definitely is one set of rules that a field obeys, and while it’s usually necessary to simplify I’d really like to know how not to. Sure, water is mostly incompressible, but it’s not exactly so, and that’s how sound works and can translate to other mediums. And then once you get down to small scales, high energies or low pressures you start seeing the individual water molecules being relevant and doing all kinds of different things. Those factors were always there, even if they weren’t relevant.
Sorry, maybe that’s a bit of a rant, but all that to say I’m sure you can find a consensus on these questions eventually.
That’s might be an option too, I guess, but in some situations it’s a different question. If I make a mistake and you ask “how”, you might just get more details. If you ask “why” I might respond with “I was tired”, which doesn’t really imply teleology. As I understand it почему would be more specific to cause rather than just means, but then again my Russian is pretty basic. The word “how” would be как, and it even works as an intensifier the same way.
Tectonic activity bends rocks all the time, even hard ones like granite. That takes a ton of heat, pressure and time. It also makes sense that in the right conditions, sheets of rock simply don’t have the room to shatter so they must bend....
Nope. The mantle is mostly solid. It’s just so huge and, under intense pressure and heat, bendy, that it still facilitates moving continents and ocean plates.
Neat! That’s a very specific, chain-like example, though, so not really in the spirit of the question even if correct to the letter. I’m also not sure what it does in the actual plastic deformation regime.
Hmm. I’m going to have to look up how you model glass bending, if that’s how it works. I wonder if you could do this in a garage setting, even. I’m not surprised a calcium mineral is less resistant to it, they seen less hardcore in general or something.
I’ve been learning some about rabies and learned about rabies causing hydrophobia. This is just a theory, I’m not saying I know anything about this topic to be knowledgeable, but if we could get someone with rabies to not fear water, could they survive?
It also illustrates a funny bit of the logic of multicellular non-clonal creatures: the germ line is the species. The other 99.9…% of you is just a fancy delivery mechanism, so it makes sense to add something seemingly super impractical to the anatomy if it slightly helps the sex cells.
It would logically have to end up on the ground. If it gets into the water would have to do with solubility, and most combustion products aren’t very soluble, so you’re probably not drinking too much smog.
I don’t actually know where they ultimately end up and to what degree they can make you sick except through inhalation. Somebody has to have studied it, though, right?
I feel like we are ways out from seeing anything like it. From what I’ve seen non-Newtonian fluids typically take a decent amount of energy to stop something and sound wouldn’t have much energy compared to something like a bullet....
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.
Particles are just a way of looking at excited quantum fields. The Higgs field is always everywhere, giving things mass.
Honestly, depending on interpretation of quantum mechanics, you don’t need to acknowledge particles exist at all. It could all be fields becoming ever more entangled and wrinkled.
But in order to do that photon actually needs to be created and travel from one particle to another.
Not really, no. At some point I’m going to exceed my own expertise here since I’m not a QFT expert, but in quantum mechanics things don’t firmly exist or not exist. The photons in question are “virtual particles”.
There’s a lot of oxygen in water by star standards, so keep that in mind. It’s possible the change in metallicity will offset any change to equilibrium temperature, although I don’t really know the details.
Could we, in theory, use something like CRISPR to give a new baby replacement super-kidneys (or whatever organ it is that makes drinking saltwater be a bad time)? It seems like if we cracked that, we’d be set as a species....
I picked up a low pressure sodium lamp and am working on a Halloween demonstration. I’m hoping to make a display that appears one way under normal light, but looks totally different under the monochromatic 589nm sodium vapor light....
CMYK actually sounds kind of complicated to do this with, so yeah look for a pre-made function to convert CMYK to CIE 1931 in whatever “normal” light you have. I can help you find the preimage from that once you do.
Edit: Oh wait, this was a Halloween thing. Maybe for next year?
I’m having trouble finding a comparable number for other animals, though. Apparently for a lot of trace elements (like copper or selenium) ruminants are actually much worse at absorption, because the microbes essentially put them into a less available form.
If two identical radios are side by side and tuned to the same frequency, will they both pick up the signal at 100%, or will they wrestle for the same radio waves?
Regarding sleep quality, why did humans evolve to require full darkness?
I know evolution is governed by chance and it is random but does it make sense to "ruin" sleep if there's light? I mean normally, outside, you never have pure darkness, there are the moon and stars even at night. In certain zones of the Earth we also have long periods of no sunshine and long periods of only sunshine....
If you have some cold water evaporating, is it possible to make it evaporate sooner by adding hot water?
How hot would it have to be?
Do we have any theories as to why complex life eventually started requiring various metal elements as micronutrients?
For example, why did zinc, of all things, start getting utilized by brain and prostate tissue in humans?
Have we been able to reproduce the conditions to bend rocks? (Even if in a lab.)
Tectonic activity bends rocks all the time, even hard ones like granite. That takes a ton of heat, pressure and time. It also makes sense that in the right conditions, sheets of rock simply don’t have the room to shatter so they must bend....
This is probably a dumb question, but if we eliminate the hydrophobia caused by rabies, would it increase the survival rate of active rabies?
I’ve been learning some about rabies and learned about rabies causing hydrophobia. This is just a theory, I’m not saying I know anything about this topic to be knowledgeable, but if we could get someone with rabies to not fear water, could they survive?
Where does pollution go when it rains?
I unfortunately live in a very polluted area, one where air quality apps mark in red and recommend that I never get out of my lair....
Could non-Newtonian fluids be used in the future as a kind of percussive ear protection?
I feel like we are ways out from seeing anything like it. From what I’ve seen non-Newtonian fluids typically take a decent amount of energy to stop something and sound wouldn’t have much energy compared to something like a bullet....
ADP keeps running ads about solar flairs that force earth into a 25 hour day. Could a solar flair even do that, and what distasters would happen if Earth's orbit changed?
Does Higgs exist in nature or is it merely artificially synthesized particle?
In nuclear chemistry elements beyond Plutonium do not occur in nature and are synthesized artificially. Is it a similar case for Higgs boson too?...
If a sun burns hotter with greater mass, does adding a tonne of water make it hotter?
Hypothetically speaking, what alterations to our biology/genome would need to occur in order for us to be able to safely drink saltwater?
Could we, in theory, use something like CRISPR to give a new baby replacement super-kidneys (or whatever organ it is that makes drinking saltwater be a bad time)? It seems like if we cracked that, we’d be set as a species....
Is there an easy way to generate a list of CMYK color values that will appear identical to the human eye under 589nm light?
I picked up a low pressure sodium lamp and am working on a Halloween demonstration. I’m hoping to make a display that appears one way under normal light, but looks totally different under the monochromatic 589nm sodium vapor light....
Humans are notoriously bad at absorbing iron from plant sources, while herbivores seem to do fine. What's up with that?
… or do they just make up for it with sheer unrelieved quantity of greenery, perhaps?