hbrav

I'd be interested in what you set up in Cambridge, if you're happy to share?

I'm a Brit who has worked in finance and AI. I honestly want to move into building hardware. My background is physics, I want to build things that make the world better. But the businesses just seem absent. One of the UK's most exciting hardware projects was Reaction Engines, and they went bankrupt recently.

I really want to know what we can do to fix this. As a country, we aren't building things that people want. Which means we are less powerful.

This sounds very similar to the method discussed in this podcast to detect rocket launches: https://www.armscontrolwonk.com/archive/1216884/detecting-mi...

This is very cool. I did my PhD in tidal interactions, but in the context of stars and giant planets - bodies that can typically be treated as having spheroidal symmetry. (In fact, one thing I was looking at was the corrections as you moved away from as assumption of spherical symmetry to include the equatorial bulge.)

The Earth's tides are far more complex because of the shape of the ocean basins, and it has quite a high dissipation rate. I'm not sure how much the internal tide contributes to that, but I suspect a lot given that the amplitude (tens of meters) is much greater than the surface displacement.

Anyway, gorgeous visualisation!

This should interest you: https://meshtastic.org/

Maybe worth remembering that "trees" have evolved many times on earth. i.e. trees do not all share a common tree-like ancestor. The woody-trunk-and-branches pattern was just useful enough that it evolved many times. Which makes me suspect that aliens would likely have something tree-like on their home world, and would have also learned to build using it.

Cargo airships are not going to replace container ships, but they may well have their niche. One such use-case is prompt delivery of supplies that are urgently needed in high quantity in underdeveloped areas. For example, delivering some grammar to the parent comment.

The individual has impunity of the department has impunity?

Not sure if you know this, but it might be of interest: in the UK speech, within the House of Commons (maybe the Lords too? I'm unsure) is specifically protected from defamation actions. An MP could stand up and say "Mr Smith murders kittens in his spare time" and Mr Smith would have no ability to sue. However, this does not apply to MPs outside of parliament.

This is extremely interesting, but reading the article left me wondering: why are experienced underwater archaeologists not involved in this? The only mention of any seems to be DRASSM, French government archaeologists who presumably had to come over at great expense. In the two locations I've lived and dived there have been underwater archaeology societies (Save Our Shipwrecks in Ontario, and the Nautical Archaeology Society in the UK) whose would normally by extremely keen to survey a wreck like this.

I'll also point out that if you don't involve people with this training, you can do a lot of harm. Items that have been submerged for a long time, especially in mud, can degrade rapidly once they're brought into air. Archaeologists will typically have prepared baths to submerge items in once they're brought up. There can be a lot of information preserved in those wrecks: for example, one of our best sources of information about English longbows are the examples brought up from the wreck of the Mary Rose.

There's one massive red flag in this article that screams "this needs archaeologists involved": the fact that they took the reporter diving to the wreck. It sounds like this was his first dive. As others have pointed out, there is some risk of injury, even if they properly briefed him, since he's going to be too distracted by the wreck to focus on things like "breath continuously". But there's also a lot of risk to the wreck. Even qualified divers have a bad habit of kicking wrecks (and reefs) and doing damage.

There's also the fact that the only photograph in that article is take from the surface using a cell phone. I would not say that underwater photography is a priority for me, but even I have the kit to take photos while diving that would be a lot better than those take from the surface. So why don't these guys? Especially in 10 feet of water where the lighting conditions are so benign.

The difference is this: in a community centre pool, a diver doesn't give you compressed air to breath at the bottom of the pool.

The thing the commentor above is concerned about is pulmonary barotrauma, a.k.a. "burst lung". Between 10 feet depth and the surface the gas in your lungs will expand by 30%. If you took a deep breath at 10 feet deep, and held it, then that expansion can cause rupture of the alveoli.

For this reason one of the first things you are told (or should be told!) in a scuba diving course is to breath continuously, i.e. never hold your breath.

I believe you mean "social cues", not "queues".

You've got exactly the right image in mind: higher partial pressure of a gas in the lungs corresponds to a higher dissolved concentration of that species (H2, He, N2, O2, whatever) in the blood and tissue.

The problem with generalizing this to quarternions is that the conjugation operation for quaternions can be expressed using arithmetic operations on the quaternion:

q* = -0.5(q + iqi + jqj + kqk)

So the analogy to complex analysis where we'd talk of z and z as independent doesn't work anymore - since we can write q* as an 'analytic' function of q.

It's not surprising you'd need something different though, since (q, q*) is only two variables and quaternions are 4-dimensional. I don't know a lot about quaternions, but Penrose introduces them in The Road to Reality and says (roughly) "yeah, they don't have the nice analytic-function properties that complex numbers have" and seems to kinda leave it at that. If anyone knows more and wants to reduce my ignorance, I'd be grateful.

This is very cool, and looks like it targets you wanting to look stuff up and I will probably use it at some point.

But I feel that anyone looking at this and thinking "oh that's cool" should also try installing Stellarium (https://stellarium.org/). It lets you see what you can see in the night sky from any location/time on Earth, and is really useful for helping you identify what you're seeing in the night sky.

I don't mean to distract from this, because it's also great. It's just a second tool that anyone with a passing interest in astronomy should be aware of.

Yeh, U[0, 1] is different because it assigns non-zero probabilities to intervals, not points. In this case we're assuming that we live in an uncountable population (each real in [0, 1] is a person), so you can't do things like assign a unique number to each person. There, even if the maniac goes on kidnapping forever, he will only kidnap a countable subset of the population. Thinking about this honestly makes my brain hurt a little.

I think it's a little different. It's like asking "what is the probability that a given coin is in the round that the player wins?" But the St Petersburg paradox isn't about that, it's purely about how many coins the player wins. I suppose it runs into similar problems when you ask about prizes that are so large that the bank runs out of coins, but I think it remains interesting even if you cap it at some finite number of coin flips. It still has the small-probability-of-huge-payout property.

If you've ever looked at the Kelly Criterion, that seems related (and in fact is one of the articles linked to from that Wikipedia page). There you maximise expected log return at each round, and I think that tames the infinity in this case (though I have _not_ checked that).

The dice room puzzle described here is a little frustrating, because no-one seems to get it right. In the finite population case the anthropic argument for "I'm likely to be the in the last round" is wrong. In the countably infinite case it can't be applied (no discrete uniform distribution on a countably infinite set). I wrote some ramblings about it here, though I'm not sure it's super-clear: https://harrybraviner.github.io/posts/2024-01-28-anthropic_d...

As you added more and more cotton candy you would begin to compress the centre under the pressure, and you would get some heating from this. I think there's a good change you would melt and cotton candy and eventually it would re-solidify into an enormous boiled sweet core, with a diffuse envelope of cotton candy around it.

The problem, if you read to the end, is that one half of the former couple is very happy with this outcome, and the other half is very much not.

> In some companies, the initial job contracts are misleading, and mention a nominal price of $0.01.

Is he suggesting that the initial job contract does _not_ state the exercise price, and relies on the employee mistakenly thinking that $0.01 is the exercise price?

This seems like it stems for a culture that we have of employees (or potential employees) just never asking questions about contracts that are presented to them. And I think there's a lot of employers that expect that to be the case too. I've once had a manager tell me with a straight face when I requested changes to a contract "I'm sorry, I can't get this changed. You'll just have to sign it." My reply of "I don't believe it's in my interests to sign that" was not something that was in his world-view.

I think it's fair to say the 'discovery' that this boson exists came with the LHC experiments. But Higgs did discover in 1964 that the Higgs boson could explain why particles have mass. His paper couldn't say "this is definitely the way the universe is", but rather "if the universe plays by the rules we think it does, this is a relatively simple way to explain this thing we see".

And in my mind, both of those achievements are awesome.

I'm afraid it becomes even worse when you learn that the concept of 'simultaneous' is ambiguous.

Consider a relatively bulky item, say, a package of paper towel. Probably takes up about a cubic foot of volume, which is 0.027 cubic meters.

Suppose you drive that into NYC in a very small van, say a Ford Transit. A quick google tells me that has a cargo capacity of 10 cubic meters. The $15 toll amortized over 370 packages would add an additional cost of 4c per package.

This is the most extreme case I could think of off the top of my head. I believe most deliveries use vans with a much larger cargo capacity than a Transit.

This seems like a general problem for a company like this: your great success demonstrates that your employees are incredibly valuable. And sometimes businesses may say things like "our people are our greatest asset", but that's not actually true. They're not an asset. Your IP is an asset, and you own that. But your people are often capable of going elsewhere and producing equally good work, and they're likely to do that if they get a better offer.

The most significant change is that any attack on Sweden would require other NATO countries to come to Sweden's defence, and vice versa.

It means that Sweden would also take part in more joint training exercises, share more intelligence, etc. with other NATO members.

A lawyer I know once pointed out that a good first step one receipt of anything like this is to reply with "Please provide me with the full name and address of your counsel so I may know to whom I should address subsequent correspondence."

If you do not receive an answer, you are not dealing with someone who is serious about taking you to court.

If you do receive an answer, you should immediately check whether that person is actually licensed to practice law (you can usually check online). If not, report to the relevant bar association that [name] is presenting themselves as licensed to practice law (don't be spooky, send the full details to the bar association).

Only if you are put in contact with an actual lawyer should you waste any energy thinking about this further.

I think "wire only" means the hook catches while the wheels are still off the deck.

I suppose that hard landing might have, in some ways, replicated the hard slam-down this would produce. Author, is that the case? Was the hard landing judged to have been a decent proxy for the wire-only arrestment?

The diagonal visibility actually looks quite poor. You could easily hide a dog, or a small child, standing close to the vehicle in the direction it's turning towards.

Boot?

They don't look very aerodynamic. But that snubby front end could give them excellent visibility, if done correctly.