This can be true of animals too - many species depend upon certain prey, micronutrients, temperatures, water parameters, etc. Others can be kept, but can't be induced to breed. Usually it's just lack of knowledge, but getting that knowledge requires a lot of trial and error and frustration.

Your answer seems to imply that if the system was spinning, you would call it higher temperature, because you can't "remove" the motion by going to the center of mass frame. I agree that it's useful to gasses to go to the center of mass frame to restore the distribution of velocities to a Maxwell-Boltzmann distribution so it looks more like a system with a well-defined temperature. However, I don't think there's anything in any reasonable definition of temperature that says "it's measured relative to the center of mass"

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Certain orchids are impossible to cultivate. My state's (MN) flower, the Queen Lady Slipper, has notoriously resisted cultivation thus far. It rarely germinates from seed, preferring to spread vegetatively. It's thought that the conditions necessary for it's germination are very specific to its natural environment - wetlands and bogs. It also takes a decade or more to mature and flower from seed, though it can live for up to 50 years. It's such a precarious and sensitive flower that it is a state crime to destroy or uproot them. I remember my grandparents had a small colony of them growing on their property by a lake up near Nisswa when I was a kid. They surrounded it with a locked fence, with a sign that read, "It is illegal by state law to pick a lady slipper flower. Anybody caught picking this flower will be shot and then prosecuted."

One thing to consider about mushrooms is that they represent a mere fraction of a much larger subterranean organism that exists in a balance with its host substrate. Some fungi are not picky about their substrate and are thus easier to cultivate. Others require a very specific substrate and growing conditions that are not currently possibly to replicate artificially.

>Why there weren’t mechanical limits on the control rods equipped with followers or other system interlocks is beyond me

To be fair to the designers, they did have to override a bunch of automatic and safety features that existed precisely to avoid accidents like that.

I'd argue that what happened in Chernobyl wasn't exactly an accident, because they deliberately put the reactor in a state where bad things would definitely happen -- as they did.

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>and causes a massive explosion that destroys half the continent

That kind of depends on how many antineutrons are actually in a liter jar, which I guess could be anywhere from a handful in a magnetic trap to a chunk with the density of nuclear matter.

Fun fact: the energy released by the annihilation of one liter of antimatter at that density (roughly a hundred billion tons) is weirdly close to the gravitational binding energy of Earth.

This is probably a decent representation of the ratio of the boron part of the rod to the graphite "tips".

https://i.stack.imgur.com/Ai7Yp.jpg

Well, theory predicts these reactions and experiments eg. with particle colliders have shown that the predictions match exactly what actually happens, to a high precision.

Indeed the theory (the so-called standard model of particle physics) is so successful that phycisists are frustrated because despite its success, it’s also incomplete, but not even the LHC has found even a hint of any new physics beyond the standard model.

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You can build an actual machine to detect muons from space (more precisely: from the upper atmosphere), for example. The particles are all very short-lived, but they do exist.

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my question is are you guys talking about real observable things or are these words you all utter theoretically? like string theory.

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There are farms in other spots of the world that grow wasabi. There's one in the UK (https://dorsetfoodanddrink.org/food_listings/the-wasabi-company)

The design of the RBMK is fundamentally backwards. It’s all about the relative values of reactivity.

Coolant (water) goes in the bottom of the RBMK and boils as it goes up. Because this is a graphite moderated reactor, water has less moderation capability than the graphite. This is important because liquid water will reduce your neutron mean free path distance (how far the neutron travels before it is absorbed by something or lost from the reactor). As the water boils, it’s density drops significantly and the mean free path length for neutrons increases.

So let’s put this together. At the bottom of the reactor, you have neutrons which are more or less struggling to find graphite, get moderated, and get back into the fuel, before leaking out or being absorbed without causing fission.

At the top of the reactor, your neutrons have a very easy time getting to the graphite to get moderated and cause fission.

This also means the power generated at the bottom of the reactor is less than the top of the reactor (axial flux tilt is top peaked).

But the top of the reactor has less coolant (because much of the water has already boiled to steam). So the top of the reactor has a tendency to produce more power, with less coolant, which is inherently a risk to exceeding critical power ratio. While the bottom of the reactor, even with all control rods out, has little power production, and is also very sensitive to emergencies which cause rapid voiding since there are typically no control rods down there just to keep the bottom of the core running.

As a result, the RBMK has control rods which come in from the top. Backwards for a boiling type reactor but a necessity.

So what’s the problem here? Where the bottom of the reactor is going to not only barely have any power output, the fuel is going to be wasted down there, it’s more sensitive to certain transients, so what did they do? They put graphite followers on the rods. To help boost the reactivity in the bottom of the core. Yes this is a dumb idea, but on its own it’s not terrible. With the followers inserted in the core, they no longer have positive reactivity to add. They already have “done their damage” so to speak. So if you had a power spike, as the rods inserted, the graphite followers would be pushed down out of the core and be replaced with control rods.

This was a “win win” for this dumb backwards reactor.

Except….. if you ever find yourself pulling the followers out of the reactor, especially if you also have low reactor coolant flow and pressure and other conditions which could cause rapid boiling, and you have low control rod density, then the effect of a scram is to push the followers back into the core and cause a power spike.

Why there weren’t mechanical limits on the control rods equipped with followers or other system interlocks is beyond me. This design “feature” should never have existed without something in place to ensure those followers cannot be removed beyond a certain position. Or better yet, don’t build backwards reactor designs.

Ok but did you remember that reaction chain off the top of your head or did you have to look some of it up?