This is actually kind of a misleading "clarification" though. Pitch is a useful example, i.e., a viscoelastic solid that will deform on long time-scales under its own weight. At room temperature and timescales sufficiently short (i.e., less than a few years), pitch would meet the simple definitions of a "solid", but observed on long enough time scales, it can be observed to flow.

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The MiG-29 and Su-27 can’t truly maneuver post stall. But their control surfaces and overall aerodynamics are designed to behave a certain way even at very high AoA and low airspeeds to specifically allow the maneuvers you named. I.e. while in a cobra, bringing the elevator back to neutral will cause drag at the tail of the aircraft which imparts a torque that will pitch it out of the cobra.

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> How viscous is the magma in the mantle?

The mantle is solid. That being said, even though it is demonstrably solid, the mantle flows like a fluid on geologic time scales and generally tends to behave like a Non-Newtonian fluid (i.e., stress and/or viscosity are a non-linear function of the strain rate). If you want a deep dive on mantle rheology (i.e., how it deforms), this slide-deck has a thorough treatment. Given that it's ideally a Non-Newtonian fluid, it's hard to ascribe a single viscosity to mantle materials, and it will vary as a function of background conditions (i.e., temperature and lithostatic pressure) and the rate of strain the material is experiencing.

> Are there points of greater viscosity and lesser?

As described above, in detail the viscosity will vary as a function of strain rate, i.e., as strain rate increases, viscosity will decrease. Those complications aside, we do have a variety of estimates for what we could sort of think of as the "background" viscosity (or the viscosity that, when assuming the mantle instead behaves like a Newtonian fluid with a single viscosity, best explains observations) for the mantle and these do vary as a function of location. For these, we typically consider the upper mantle (nominally the mantle above 660 km) and lower mantle (mantle between 660 km and the outer core) separately.

For the upper mantle, this has a pretty wide range of viscosities anywhere from 10^(18) Pa s to 10^(21) Pa s (e.g., Dixon et al., 2004) with significant lateral variability. As discussed in that paper (and other sources), this high degree of variability is largely ascribed to differences in water content or temperature that reflect both modern and past tectonic histories and where higher water content and/or higher temperatures lead to lower viscosities (i.e., materials that flow easier / are effectively weaker).

For the lower mantle, depending on the source, similar order of magnitude ranges have been suggested but tend to be uniformly higher and the variations are more in terms of depth as opposed to laterally. For example, both Lau et al., 2016 and Mitrovica & Forte, 2004 suggest viscosities ranging from 10^(21) to 10^(23) Pa s with lower values at the top of the lower mantle and a peak in viscosity near the bottom of the lower mantle (though all estimates suggest that viscosity decreases significantly to <10^(20) Pa s approaching the core-mantle boundary). In contrast, other estimates like Cízková et al., 2012 and van der Meer et al., 2018 suggest less variable lower mantle viscosity mostly between 10^(22) and 10^(23) Pa s but still with a peak near the bottom of the lower mantle.

It's worth briefly discussing where these numbers come from. For the upper mantle, it's primarily from using the response to glacial isostatic adjustment, i.e., the lithosphere flexed down under the weight of large ice sheets and is still flexing back up after they melted and the rate and spatial patterns of that flexing back up (which we can measure) is in part controlled by the viscosity of the mantle (we also use similar response to responses to large loads like lakes, etc to work out viscosity estimates for areas far away from those that were glaciated). Similar data is used for some of the lower mantle estimates (e.g., Lau et al., 2016 and Mitrovica & Forte, 2004), but alternatively, papers like Cízková et al., 2012 and van der Meer et al., 2018 both use the sinking rate of detached subducted slabs imaged by seismic tomography to estimate viscosity.

> If it weren't for the heat, could you swim in it? What's an everyday substance that might have comparable viscosity?

For reference, the viscosity of water is around 0.001 Pa s, higher end viscosities of honey will be around 10 Pa s, average peanut butter is around 100 Pa s, and the viscosity of pitch (e.g., pitch drop experiments) is ~10^(8) Pa s, so still at minimum 10 orders of magnitude less viscous than the least viscous part of the mantle.

In short, the viscosity of the mantle is high enough that on human timescales, a material with a similar viscosity at room temperature would be for all intents and purposes a solid, so no, you could not swim in it. This is why we talk about the mantle as a solid. It is in the way we experience solids, and the fact that it has a viscosity and flows is only relevant if you're considering timescales of several thousands or tens of thousands of years at the minimum.

Solubility of phases and their precipitation is not really related to their melitng points. Things can dissolve or precipitate at wildly different temeperatures.

How close are we to be able to see widespread use of nanobots in medical applications?

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It is a stall, but one that is recoverable (for the cobra)
The body is slammed into the air as an air brake, the first part of getting the nose up is a rapid stall to prevent the aircraft just climbing and flying up.
The aim was to maintain the altitude during this, so a rapid lift of the nose, a stall of the wings so it doesn't gain a lot of altitude and also I believe an engine set up which can still work taking in enough air to give plenty of thrust to hold the altitude.

Regaining level flight is apparently from the elevators, the nose-up airbrake is somewhat stable but once you're back on the elevators, you get more drag at the back (bottom) of the wing, and it flips the nose back down again.

So- way over the angle of attack, stall the wings so you don't gain altitude, plenty of thrust so it won't sink, plenty of drag and slowing down. Then on with the elevators, adding extra drag at the bottom (still stalled, the air isn't flowing over the wings) and it'll flip the nose back down and you recover.

hi! curious layperson here: how do you physically equip the bacteria with something unfamiliar to them?… do you ask nicely? 😁

If I am super rich and predisposed to a type of cancer how much money would I need to get to that point as to afford using new science and tech that you are using?

What could be the side effects of this type of technology?

What is your opinion on the last of us and the fungi turning people into zombies?

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There is a pretty extensive literature (which is not exactly hard to find) of climatic variability, drought, and influences of these on various societies in the Middle East / SW Asia at both long (e.g., Kaniewski et al., 2012, Xoplaki et al., 2016, Flohr et al., 2017, Jones et al., 2019, Fleitman et al., 2022) and short (e.g., Donat et al., 2013, Barlow et al., 2016) time scales. The general point is summed up nicely by the title of the Kaniewski et al., 2012 paper, i.e., Drought is a recurring challenge in the Middle East.

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True hibernation is a long-term period of dormancy...weeks, or even months of continuous metabolic slowdown. Going into and out of it takes hours. Very few animals actually hibernate—certain snakes, bees, and bats, as a few examples. They generally stay "asleep" for the entire period, perhaps waking up only rarely to relieve themselves.

Torpor, instead, is much more short-lived, and generally involuntary...when it's cold their metabolism slows down and they conk out, if it warms up they get up and stretch and move around, maybe go find a snack. A lot of "hibernating" animals really just experience torpor during cold nights for a season, but are still somewhat active most days.

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Asthma, allergic rhinitis, and eczema are all statistically more prevalent in children of households with animals present than without. This was a hospital-based study that looked at Qatari children, so the mix of animals (cats, goats, birds) weren't exactly the same mix as you'd find in, say, the USA, but the statistical significance was very strong (p=0.008 to p=0.0001)

This study of Dutch children was a little more interesting, as it looked at both current and past pet ownership (dogs, cats, rodents, or birds). People who have always had pets (and still do) were actually the healthiest, followed by people who had never had pets. So if you stopped reading the paper there, you might think "oh, maybe having pets is actually good for your respiratory health!" But the researchers also asked about respiratory symptoms (asthma, coughing, wheezing, etc.) in people who used to have pets but no longer have pets...and often, those households no longer have pets because the children had developed respiratory issues. And some of the people who never had pets made that choice precisely because they had pre-existing respiratory issues that they did not want to aggravate. So it's not enough to look just at who currently has animals, because people change their behavior over time, and sometimes in response to the very variables you're trying to study.

In short, yes, it appears that living with animals (especially cats) increases the risk of developing respiratory symptoms like asthma, allergies, wheezing, etc...and that those symptoms persist at a higher rate than experienced by non-animal-owners even if the household goes animal-free.

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