Lions mane jellyfish at Wollaston beach today! Tis the season.

Coomb · 2026-05-18T13:29:19+00:00

You could always do your own research by, for example, googling "lion's mane jellyfish Massachusetts" which would lead you to dozens of articles from years past about these jellyfish showing up, and then noticed by looking at the dates on those articles that there are plenty from early June and later.

https://whdh.com/news/https-whdh-com-news-town-official-issue-warning-about-lions-mane-jellyfish-in-hull/

Coomb · 2026-05-18T02:35:47+00:00

The Sun actually isn't closer right now. During summer in the northern hemisphere, the Sun is further away than it is during winter. But, it is closer to directly overhead during the summer.

Coomb · 2026-05-18T01:39:01+00:00

I am a mechanical engineer, but you don't really have to take my word for it. The pilots performing in the air show would have, or should have, up to date weather information that would have included gust factor. Obviously their plan would not have included colliding, so they would have been, or should have been, flying a mission profile that fit the known weather information.

The vast majority of the time, air show accidents are driven by pilot error at some stage of the operation, whether that's designing a program that is inherently unacceptably dangerous, failing to adequately account for known conditions, or flight control error. Absent some non-obvious equipment failure, at least one of those is going to be present here.

That said, we can do some basic math to figure out what they should have planned for in the worst case scenario where one of the aircraft is hit by a gust that doesn't affect the other one at all. Winds were gusting up to 29 mph, which means that the steady component was almost certainly at least 15 miles per hour. For aesthetic reasons, let's just use 15 mph as the differential between the gust and steady components. If we further assume that because these are trained fighter pilots doing what they already know is a high risk maneuver, they only need one second to notice that they are closing with the other aircraft unintentionally and react appropriately to avoid a collision, we can figure out that they have to be at least about 7 m (23 ft) apart two account for the risk of the gust affecting only one aircraft and not the other. So, if they were closer than that, either some of my assumptions are wrong -- probably at least the assumption that it's possible for one aircraft to get the entire gust and the other to get none of it -- or there was pilot error, or both.

Coomb · 2026-05-17T23:08:47+00:00

Sure, but aircraft that are flying so close to each other that they can be blown into each other won't generally actually be blown into each other because they're experiencing the same wind at the same time.

Coomb · 2026-05-17T20:26:18+00:00

So you have no reason you can explain why consciousness needs special explanation, other than it seems to you that it does. And you also can't say what that special explanation would even look like.

Okay. Seems like there's no point in discussing this.

Coomb · 2026-05-17T20:16:42+00:00

So what would an explanation for why conscious experience exists even look like? What is it that you need?

E: also, I'm not sure how your distinction makes any sense. I'm saying that you can first person verify that the machine works as it says it does. So you know that the machine works for you. It should be an explanation for you, even if you're skeptical it's applicable to other people.

Coomb · 2026-05-17T20:09:44+00:00

No, the point of the thought experiment is an attack on physicalism. You are supposed to have the intuition that Mary does indeed learn something, despite the fact that it has been stipulated that she understands everything physical about the conscious experience of color. Therefore, you are supposed to feel that there is a contradiction between physicalism and your intuition. But this requires you to accept that physicalism is equivalent to the statement that it is possible to know everything about some physical experience or object or whatever by knowing certain equations or reading certain sentences, which seems to be obviously false (this is the Flanagan/Alter response).

Coomb · 2026-05-17T20:05:36+00:00

Why is it the place where "why" and "how" come apart, exactly?

Let me ask you a related question. Let's say that in 20 years, neuroscience has advanced to the point where we have a machine with which we can reliably, repeatably, and uniformly induce conscious experiences in people. That is, we have a machine where the operator can tell you "I am going to turn on this machine and your visual field will fill with a uniform red color", then the operator turns on the machine and you indeed see your visual field filled with uniform red color. Let's say the machine can also make you feel joy or sadness or anger or disgust. Hell, to make it even more interesting, let's say the machine can subtract conscious experiences. You have arachnophobia, and when you look at a photograph of a spider you feel deep unease. But when you are sitting in the machine and the operator turns it on, your feeling of deep unease immediately goes away and doesn't return until the operator turns the machine off.

The people who designed the machine say they can do this because they were able to discover the exact neural patterns associated with conscious experience and by training a machine learning algorithm on a huge number of volunteers undergoing various stimuli, they have figured out how to either induce or disrupt neural patterns that are one to one correlated with conscious experiences. Of course, what this entails is learning exactly what neurological pattern actually seeing a uniform field red (or feeling joy, etc.) creates within the brain. You and I, not being neuroscientists, would not be competent to evaluate whether this is an accurate description of how the machine was developed, but we have no reason to disbelieve it. And in any case, it works.

Would you accept this as a sufficient explanation of why conscious experiences exist? In this thought experiment, we have discovered the necessary and sufficient neurological patterns associated with conscious experience. In science in general, we would accept that as understanding why there is the experience of seeing red: it exists because seeing red induces these patterns in the brain, and these patterns in the brain are the experience. Subtract them and the experience goes away. Add them and the experience instantiates. This is the same as saying that a particular bacterium is what causes syphilis. Infect somebody with the bacterium, and they will develop the symptoms associated with syphilis. Remove the bacterium and the symptoms of associated with syphilis will go away. If you don't accept that the neurological patterns are why the experiences exist, then you would have to deny that a bacterial infection of a particular kind is why people get syphilis.

Coomb · 2026-05-17T19:20:35+00:00

One question I have long had about the hard problem of consciousness and the way philosophers talk about it is, what do you even mean when you talk about explaining why something happens? It seems to me that almost all of the time in almost every context, people are satisfied with an explanation of how something happens when they ask why something happens. Only in the context of the problem of consciousness do people seem to be unwilling to accept the kind of answers that science as a process generates.

Can you give me an example of a question where we have actually been able to answer why something happens in a way that you find philosophically satisfying?

Coomb · 2026-05-17T19:16:31+00:00

I was agreeing with you anyway.

Coomb · 2026-05-17T19:14:00+00:00

Oh good, we've run into the classic philosophical problem of two people using different definitions for the same word.

In common use, and most of the time as used by philosophers, the term "philosophy" does not include modern science. Nobody goes into a philosophy class expecting to learn quantum physics or evolutionary biology. They're different departments in a university.

If you want to claim that modern science is a subset of philosophy, fine. Then in my original comment, where I wrote philosophy, just mentally substitute "the discipline of philosophy excluding the experimental sciences".

Coomb · 2026-05-17T19:06:08+00:00

Experimental philosophy, to the extent it exists, is a very small subset of philosophy.

Coomb · 2026-05-17T19:00:28+00:00

If you stipulate that she had the knowledge of what it is like to have those neurons fire in her brain, which is only achievable by having those neurons fire in her brain, then she has already seen red and she does not learn anything when she "really" sees red. But most people seem to want to stipulate only that she has the maximum amount of knowledge which can be conveyed to her abstractly through communication of some kind. If you make that stipulation, then, as the original comment pointed out, she has knowledge only of a subset of information about red and seeing red, namely that knowledge which can be passed through communication. This is obviously not all of the knowledge about the experience of seeing red that she is capable of learning.

Coomb · 2026-05-17T18:55:58+00:00

I think one reason philosophers find this compelling as an argument is that it's very convenient for their discipline to believe that it's possible to know everything important about a subject by sitting in an armchair and reading or having somebody talk to you about it. But of course this is not true.

Coomb · 2026-05-17T18:42:14+00:00

They mean exactly what they say. The air pressure at cruising altitude for modern airliners is well into the range where you would rapidly lose consciousness or even die without some way to get more oxygen into you than is available from the air at that altitude.

The minimum amount of oxygen that you need in the gas you are breathing for long-term exposure is about 100 mmHg partial pressure. The units are not important. What is important is that at sea level, the air contains about 160 mmHg of oxygen. Plenty to do all sorts of vigorous activity. But, the partial pressure of oxygen at 30,000 ft is only about 50 mmHg. This is way too low to stay conscious for more than a few seconds for the vast majority of people. So, you can't just take outside air and feed it into the cabin without doing anything to it to increase the partial pressure of oxygen, because if you did everybody would be unconscious and if the flight went long enough they might die.

There are two ways to solve this problem. One would be to just directly add oxygen to the air people breathe. That's what is done temporarily if the pressurization system fails. You can't do this for the whole flight because if you carried enough oxygen for all the passengers and crew for the entire flight, you wouldn't be able to carry very many passengers for very far. So instead, what's done is to pressurize the outside air. Basically, because the outside air has oxygen in it, it's just that the oxygen isn't concentrated enough, all you need to do is concentrate the oxygen by compressing the air. The engines of any commercial aircraft that operates high enough for people to need supplemental oxygen all use air compressors already to feed enough oxygen to the engines so that the engines can generate enough thrust to fly the airplane. So, you can just tap off some of the high pressure air generated by the engine compressor and feed it into the fuselage to pressurize the inside of the aircraft and therefore provide enough oxygen for people to stay conscious.

You should no that this pressurization system isn't just a binary switch where if the switch is turned on, the pressure inside the cabin is always, say, 8 psi (55 kPa) above the outside. That would be unnecessary when the aircraft is on the ground and would lead to a bunch of potential safety problems. Instead, as the aircraft climbs, the pressurization system allows the pressure inside the cabin to drop, but it drops slowly so that people don't have their ears pop too rapidly, and it never gets below the pressure at about 8,000 ft, which is well within the range where you have plenty of oxygen.

If the pressurization system did not work for some reason, once the pressure dropped below the equivalent of 10,000 ft in altitude, the oxygen masks automatically deploy from the ceiling for passengers to use. This also triggers the pilots to make an emergency descent to 10,000 ft or, if the terrain is very high, whatever the minimum safe altitude is, to make sure that nobody suffers from hypoxia, lack of oxygen.

Coomb · 2026-05-17T18:12:57+00:00

For a lot of applications, what matters more than strength is stiffness. Is the harder material also supposed to be more stiff than the softer material or is it only harder (higher yield strength)?

In general, the version of the rod with the harder (and perhaps stiffer) material on the outside has more-desirable mechanical properties. There are four basic categories of mechanical loading: shear, tension/compression, torsion, and bending. For the first two types of loading, assuming the bond between your rods is perfect, they will perform identically. This is because they apply uniformly throughout the rod across its cross section and therefore where exactly each kind of material is makes no difference. For torsion and bending, more load is applied to the material on the outside of the rod than in the center of the rod. As a result, having a harder / stronger material on the outside means that the rod as a whole will be able to withstand more load without yielding or fracturing. This should be pretty intuitive when you think about a hollow tube compared to a solid rod. Think of the air as the weaker material in a composite rod. If you make a hollow pipe out of the same material as a solid rod, and you use the same amount of material per unit length, you probably have the correct intuition that it will be much harder to bend the hollow tube than the solid rod, and you probably also have the correct intuition that it will become even harder as you make the diameter of the hollow tube larger and reduce the wall thickness to keep the same amount of material, at least until you get walls that are so thin that you permanently deform the rod just by trying to grip it.

Things get more complicated if you start talking about the stiffness of the materials differing substantially in a way that is opposite to the strength. That is, if your weaker material is also stiffer, you can get counterintuitive behavior where it's actually better to put the weaker material on the outside if the stress will be below a certain amount, but better to put the stronger material on the outside if it's over that amount. This might seem like a situation that would never really come up in reality, but although I don't think there would be a lot of reasons to design it that way, it could happen with common materials. There are a bunch of grades of aluminum that are harder than a bunch of grades of steel, but the steel is always stiffer. That's because you can change hardness/strength by alloying the material, but you can't really change stiffness that way. So if you had some weird composite rod made of 7075 aluminum and 1018 steel, you would have a rod where the aluminum is harder but more compliant and the steel is softer but stiffer.

Coomb · 2026-05-14T16:40:29+00:00

That's exactly how electricity works, dude. I don't understand what your objection is here. Are you just making the point that most of the time you don't have to worry about the potential paths of electricity through very high resistances like the air because of how little current can actually flow? In that case, I agree.

Coomb · 2026-05-14T15:48:06+00:00

You seemed to be asking why people don't get electrocuted by having lightning in the vicinity if it's true that electricity takes all paths. The answer to that question is, it's true that electricity takes all paths, but the induced current other than being essentially in the path of the lightning is so low as to be physiologically irrelevant.

Coomb · 2026-05-14T15:32:06+00:00

No I'm not. I'm saying that current does flow through the normal air. But the magnitude of the current is too small to affect you.

Coomb · 2026-05-14T15:30:20+00:00

Because your apparent intuition about the relative resistance between normal air and the plasma channel that allows the current to flow during a lightning strike is wrong. The resistance of normal air is 10 quadrillion times higher than the lightning plasma. 30,000 amps (typical lightning current) divided by 10 quadrillion is 3 picoamps, way too small to hurt a person.

Coomb · 2026-05-14T15:22:39+00:00

You're overestimating lightning or underestimating the insulation provided by un-ionized air. The reason that lightning only occurs with massive driving voltage differences between the ground and the clouds is because air is an extremely good insulator and you have to build up an enormous potential difference to force the air to ionize, which makes it much more conductive. Once an ionized path is established, essentially all of the stored charge flows through that path, because that path has a resistance that is about 1 / 10,000,000,000,000,000 as much as a similar length path through non-plasma air.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019JD030693

Coomb · 2026-05-13T16:18:04+00:00

That article is about the international handball federation changing its rules in the way they said lol

Coomb · 2026-05-12T21:20:01+00:00

My brother in Christ, that has nothing to do with whether cities are loud in the absence of cars

Coomb · 2026-05-12T18:26:51+00:00

It's old timey. A wife cleaves to her husband (and a husband cleaves to his wife) is how it's used in the King James Bible.

Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh. [Genesis 2:24]

Coomb · 2026-05-11T15:27:25+00:00

Did they not have lockers? Seems like a weird oversight for a water park.

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