Quantization is a consequence of what happens when waves are bounded. In particular, quantization of energy, and therefore rest mass. Since all of the particles modeled by QM or QFT are done so in terms of wave equations, quantization of the solutions is a natural consequence.

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It would help to narrow down this question quite a bit more. For instance, what do you mean by "economy" or even "value"? An economy in the broadest sense is just a grouping of interdependent entities (people) all trying to do things they want/need to do. Sometimes goals overlap and individuals form larger groups (institutions) to better achieve those goals. Forming a School, a State, a body to oversee a Currency... these are all results of some form of collective decision making (note: NOT necessarily democratic either!). These institutions serve some better than others. Entities and people try to achieve goals the best they can within and around them. As such, "how" the economy functions is directly related the the institutions (policy) in place.

So an economy in a political system where people look out for themselves will look different from one where corporate interests come first or one where more public or collectivists interests are the behavioral norms.

There will always be some kind of "economy" as long as people are interdependent in their goals.

If you want a more academic and in-depth overview specific to western economy and how we got here, "Institutional Economics" by John R Commons is incredibly cohesive. There are also more modern books on the topic.

Yea I was just informing that the surface area increase also correlates with an increase in normal force. Idk how it interacts just that it was missed.

The main problem with covid actually was that the world did not screech to a halt. I think this grew quit uninterrupted for about three month until lockdowns started to his in Europe and the us. Granted, who could have known and most of us were numbed from media talking about klller viruses ever two or three years…

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It's because using air drag to slow you down saves enormously on payload fuel mass.

If you are coming down near Earth from a very high position, you will sweep by the Earth going way too fast to stay in low earth orbit. You'll just fling past Earth and rise up high again. So if you want to dock with something in low earth orbit, like the ISS, you have to decelerate a lot. That excess speed has to be removed to slow you down into a relatively circular orbit at low altitude.

And if you are going to do that decelerating in space, not touching the atmosphere, you have to provide all the deceleration yourself. With your own fuel.

But if you pass really low to Earth, so you are scraping the atmosphere, then the atmospheric drag can provide all the deceleration you need without you having to spend fuel doing it yourself. Granted, that means you need protection from the heating effects of the pressure shock, but if you can handle that heat you gain the advantage of needing no propulsion to decelerate with - that means not needing a powerful engine and not needing fuel for that powerful engine.

Merely having a very small bit of fuel for a little steering engine that can merely slightly deflect your path is sufficient. All you have to do is slightly bend your path long before you get to Earth, to ensure you hit the atmosphere just right. That's more of a computing challenge than a delta-V challenge.

And you don't even need to put that computing power on the probe itself. You can have the probe have just enough smarts to obey any maneuver command you send it, and then use more powerful computers on Earth to calculate the needed maneuver to beam to the probe. (This is basically how they did this sort of thing in the 70's when the math required room-sized computers.)

I didn't cover it yet, but if you try to do your own self-propelled deceleration to turn a high-speed Earth flyby into a low Earth orbit, it's not sufficient to have a little bitty weak steering engine. You need to ensure that engine has a significant level of thrust because it doesn't just need to spend a lot of delta-V, it has to spend it fast. If it's one of these super-efficient but also super slow engine designs, such as a weak little ion engine, the probe won't slow down fast enough and will slingshot past the Earth back up to a high altitude before it has caused enough delta V to do much.

tl;dr - Needing a heat shielding arrangement for the bit where the probe hits atmosphere hard does add a little bit of mass, but not nearly as much mass as it would take to have a high-thrust engine and the fuel to run it so you can provide that deceleration yourself.

And since we're talking about the mass at the very end of the mission, in the final payload that comes home, that's mass you have to carry at the tip of the rocket through all the stages along the way. The very last stage of the mission is the most important place to save on mass. 1 kg more mass in the final stage can mean more tonnes of mass added across the other stages that come before it.

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Question for all 4:

How does the connectivity and rapid exchange of ideas online impact linguistic continuity and evolution of social interaction, and what are foreseeable socioeconomic impacts in regards to relatable marketing in the future?

Makes sense tbh. Statistically there are more men working extra hours than women, given the time that the latter need to dedicate to pregnancy/post-labor. So average salary gap numbers will reflect both actual cases of discrimination and also performance/dedication-based differences. Corporate HR departments cannot magically disentangle the two of those from their multiple business units (as extra hours / overall dedication are not necesarilly easily tracked), so they need to make broad adjustments. Given a fixed personel budget, its easier to lower average salaries to comply with policy

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If time is the fourth dimension, is it possible that all of time flashed into existence beginning to end in a zero time instant and everything is written?

If not, what did Einstein mean when he said time is an illusion?

Is it possible that dolphins communicate as type of underwater internet and that Is one reason we can’t communicate, as we are trying to speak to individuals rather than the whole? Sound travels much farther underwater.

That’s not necessarily why HIV is hard to make a vaccine for. People can be infected for years without it damaging their immune system to the point where it can no longer mount a defense against HIV. People DO develop robust immune responses to HIV, that’s actually what an HIV+ diagnosis is - positive for HIV antibodies.

Part of the problem is what we think we’re talking about when we say “immune”. Becoming vaccine-immune to something doesn’t mean that none of your cells will ever become infected by that virus, it means that your body will recognize the signs of infection on your cell surfaces and destroy the infected cells before the infection progresses to the point where you’re acutely sick.

The problem is that HIV is incredibly efficient at evading exactly that immune response. It’s not a regular RNA virus that hijacks the entire cell and rapidly reproduces until the cells explode. It’s a retrovirus that transcribes itself right in to your DNA and slowly (relative to something like influenza) buds off new viral particles without immediately killing the cell it’s infected. Your body could be chock-a-block full of HIV antibodies, but if even one viral particle gets through and infects a CD4 cell, there is a high chance it can churn out enough viral particles to produce systemic infection before your immune system notices there’s something amiss with that one specific cell. This is what happens with any infection you have vaccine immunity to - some number of cells will become infected and produce more virus, but in HIV’s case, one of the first places those newly produced viral particles will go are your latent or resting immune cells. These cells won’t immediately begin transcribing any new virus and and HIV writes itself right in to their DNA. It effectively hides itself from the immune system by writing itself in to the DNA of your immune system. That’s also why treatment has to be lifelong. Those latent or resting immune cells can wake up at any time and start the whole thing over again. Some naturally do every day in every human body through the normal functioning of your immune system.

It’s why drugs like PrEP work and vaccines don’t. PrEP, when taken correctly, stops HIV from reproducing at all. So even though some random CD4 cell near the exposure site might become infected, it can never make any new HIV particles and that cell will eventually be cleared from the body through natural processes. It can’t progress to a latent reservoir of infected cells that can permanently hide from the immune system. It’s also why PEP (post exposure prophylaxis) can work, if taken early enough.

Even if the sample tube attaches to the exterior of the space station, at some point they will have to bring it inside to transfer it to the reentry vehicle & every set of hands touching it is another opportunity to contanimate the sample.

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Why are there multiple languages at *all*? I would think there's only one, or a few, convenient and effective ways to communicate information via flapping meat(so to speak). Why, then, are there so many languages that oft times are not very compatible with eachother?

Do we know, or is it possible, that we artificially selected humans to be hairless to psychologically distance ourselves from animals?

We kill them en masse for food, religions draw distinct divisions, we see ourselves as superior.

Are there other things that we may have artificially selected for?

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It’s largely based on whether or not your own immune system is able to clear the virus or not.

Catch measles? Your immune system will kill it and remember it well enough to protect you forever. All you need to do to make a great vaccine is to use killed virus.

If you’re talking herpes or HIV, your immune system can’t root that out and kill it once it’s in there. The only hope of vaccinating is to prevent every last viral particle you encounter from ever being able to enter any of your cells. That’s a much more difficult prospect.

Sometimes the answers also come for political or project management reasons, as much as physics and scientific reasons.

The ISS is slightly risky. It is hard to know how much longer the ISS will be there for. It is currently funded and authorized through 2030, with deorbit scheduled for 2031.

There are other reasons that could potentially shorten the lifespan of the ISS further.

A sample return mission might take 10-15 years (or more) to plan, get approval and funding for, to build the hardware for the mission, to launch that hardware, and the time to get to and from the sample location. (In addition, often these are tacked on to other missions; which might include a science package that has more duration.)

If a mission would use the ISS as a critical component for it's return journey, that means that the mission assumes extra risk based on the likelihood of the space station being available for it's role in the mission at the end of the mission.

And while we can certainly assume that the Space Station will be funded for longer... the PM and approval teams cannot assume this. This means that if the project is expected to take 10 years, the project cannot use the ISS, because on paper the ISS will be gone by then.

So the question becomes: does using the ISS as a return link outweigh the risk and scheduling complications? Given u/electric_ionland's very nice response, my guess is "no".

Note that I don't work for NASA, any governmental agency, or any governmental contractors.

Railway and motorway embankments. Serious earth moving projects will be the last things to disappear.