I suspect that would fall under the rule that if two black holes’ respective event horizons ever cross, they merge and initiate the eventual merger of the two respective black holes.
I've seen this vaguely referenced, but when I dig in I don't find support for it.
It's far from obvious that just because the event horizons (which is just a mathematical concept and a 3D area of space) should control the trajectory of the singularity.
With two identical blackholes, with a event horizon of radius R, why should a singularity 2R away be unable to escape?
Not only are these aircraft hangar sized buildings with soundproofing, they’re also likely wired for hundreds of amps of lighting, including truss and catwalk systems to he able to position and distribute that lighting.
I suspect if you're wary about fomite spread of disease (later shown to be airborne for COVID but initially assumed), then it's easy to pick up a phobia of grappling the handlebars of a scooter that a stranger has recently used.
Additionally, at least anecdotally here, as the city centers hollowed out of normal business/leisure traffic, a lot of the rental vehicles were visibly breached and used by homeless folks, which often tarnished the literal appearance and reliability of the rental units in addition to damaging the brand.
It’s less that this allows new unprecedented weapons, and more that this allows one to validate material properties in similar conditions to a nuclear bomb detonation without actually testing a full scale device. This lets one verify and refine the otherwise “magic number” constants in computer simulation code that were empirically derived 50-80 years ago.
Of course, if you’re a nascent nuclear power along the lines of NK, you just do full scale tests, treaties be damned.
North Korea hasn't signed any treaties abolishing nuclear weapons tests. In point of fact, the USA itself hasn't ratified[0] any treaties prohibiting the type of underground tests the DPRK has conducted. The US chooses not to do those (and has maintained a voluntary moratorium since 1992), but is under no obligations.
Notwithstanding the US's deeply hypocritical stance on treaties it hasn't ratified but others must follow, North Korea did in 1985 sign the NPT which forbids them even building nuclear weapons, as well as the 1992 "South-North Joint Declaration on the Denuclearization of the Korean Peninsula" where they explicitly pledge not to test nuclear weapons (which they indeed didn't do until 2006).
An agreement was made to suspend the nuclear program in 1994, the US then refused to certify it after 9/11 due to NK's transfers of technology to Iran.
Whatever anyone thinks about that, it's got nothing to do with the 1994 agreement (which is easy to read, it's only a few pages).
NK subsequently withdrew from the NPT, and got a nuclear weapon in 2006.
> South-North Joint Declaration on the Denuclearization of the Korean Peninsula" [...]
I believe that NK's stance on the matter is that SK is hosting military bases for a foreign nuclear armed power (the US).
So it's implicitly threatened by a US nuclear attacks, and that threat became explicit under Trump.
You know, the best part is that US is doing this same thing with the incoming president shitting on the work on the previous president for the sake of domestic politics, and not getting a new deal with the belligerent state!
So instead of Clintons deal Bush tore it up, didn't get anything, and now North Korea has nuclear weapons. And instead of Obamas deal Trump tore it up and got nothing. Now Biden also wants a new deal, so we know how this version of story likely ends (especially with Bibi bombing out of control, the pro-nuke factions in Iran have great fuel for winning the go/no-go argument on building a weapon.)
This gave me a bunch of insight into the workings of those old survival tricks of using analog watch hands to find cardinal directions:
- Since the video starts at solar noon, the sun is always at 12:00 relative to the video.
- Swapping reference frames, if you had a clock face with 24 hours on it, and aligned the "12:00" to point at the equator, the "0:00-12:00" axis would define a longitudinal plane through the Earth, and the hour hand would define a second plane that would intersect with the sun--the hour hand would "follow" the sun.
- Conversely, if you pointed your clock's hour hand at the sun, you would know your "12:00" would be due north/south (depending on hemisphere).
- The same is true for conventional 12-hour watches and clocks, but you must find the "half-way" mark between your hour hand and noon, because the hour hand is moving at twice the speed relative to the hypothetical 24-hour clock.
> Conversely, if you pointed your clock's hour hand at the sun, you would know your "12:00" would be due north/south (depending on hemisphere).
Not quite. In the southern hemisphere the sun moves 'backwards', so you have to flip the clock backwards, or instead point the 12:00 mark at the sun and then the hour hand shows north/south.
Just a word of caution for anyone that would want to use thos in an actual survival situation. If you're really lost, the best thing to do is stay put and wait for someone to find you. If you have to move, knowing which direction is North is pretty useless unless you know enough about where you are and the surounding area. And even then, in such situations, topographical landmarks will likely be more useful.
Not to be a nay sayer, it can be fun to do, and perhaps even useful in some situations. But probably not something that's going to save your life, no matter how many time Bear Grillis used it.
I suspect that they would, if for no other reason that if the direct action is indiscriminate in whom it harms, then the well-heeled will have the resources necessary to seek compensation via litigation while the marginalized will be out of luck.
I disagree; under normal circumstances regarding the HE explosives you are 100% correct but I suspect a nuclear shockwave at near point blank range might be fast enough to push the near side of the primary pit to the far side in a time interval short enough to cause an additional criticality. Probably not to design yields, but plausible.
A nuclear chain reaction takes place roughly over a single microsecond. To travel the ~11 inches of a bomb, in ideal circumstances, a high explosive needs roughly 200 microseconds. It is not impossible that the exact right stuff could happen to trigger the bomb, but it is extremely unlikely - it took the smartest minds in america working together for 3 years to figure out the exact precise timing to prevent a nuclear fizzle and achieve a true atomic explosion. It is, contrary to pop culture, near-impossible to pull off by dumb luck. Mostly you'll just make a radioactive mess.
Right! But that's talking about compressing a plutonium pit in atmospheric pressure--being an extremely dense metal, plutonium will preferentially "squirt out" in any direction rather than compress, if there's a direction it can go in. Therefore, you need to make a spherical shockwave via explosives.
But that's in 1 atm! The initial wavefront of a fission device is going to be conservatively about 4 inches a microsecond (based on early above-ground test photos, modern high-yield devices would probably be faster still). This could very well turn the entire physics package of the secondary weapon into a thin pancake on the blast front, the plutonium can't get out of the way fast enough to avoid compression. This is a totally different scenario than a one-point-safety fizzle. The HE explosives in the second bomb might as well not exist relative to the overpressures faced from the first bomb's detonation.
Another point is the massive neutron flux, which will get some nuclear reaction out of the bomb material in and of itself. Neutrons will set off both fission and fusion reactions, simultaneously.
I wonder if you had two bombs in a confined space whether the X-ray flux from one would cause a radiation flux driven implosion in the other - similar to how the primary causes the secondary to implode in an H-bomb.
I was thinking the same, given that Teller, Sakharov et. al. came up with, but discarded as unworkable, several designs (the "Classical Super", the "Layer Cake"...) before they discovered that, unfortunately, there was a way to make it work. My guess is that the X-ray pulse from a buried bomb would be quickly absorbed (it is quite rapidly attenuated just by air), and that whatever X-rays reached the second bomb would all be from one direction, ruining the symmetry that is apparently needed for fusion ignition.
On the other hand, I have heard that a non-trivial part of the yield of a hydrogen bomb comes from the fast neutrons from the fusion causing a much more complete fissioning of the fissile material. Maybe, if the buried bomb was not damaged to the point where it was incapable of fusion ignition, the second bomb would contribute to the explosion in this way, without acting as a hydrogen bomb itself. With a high enough neutron flux from the first bomb, maybe the core of the second one would not have to undergo implosion, or even stay intact.
The article also talks about a 17-mile kill zone, and the creation of a new "North Carolina bay" despite the crash being 50 miles from Pamlico Sound. These seem to me to be incompatible claims, and surely the second, at least, must be hyperbole?
"non-trivial part of the yield of a hydrogen bomb comes from the fast neutrons"
I believe in almost all "H-bomb" designs most of the energy produced comes from the fissioning of various uranium components by those neutrons (mainly the "pusher" surrounding the secondary and sometimes the surrounding case enclosing the primary and secondary - e.g. in the W88).
I suspect in reality the increasing compensation of the executive suite in stock, while intended to alleviate the principal agent problem, means that it's substantially more remunerative for leadership to try to goose their stock price by whatever means possible within their tenure than to steer the ship in a growth-agnostic fashion. Doubly so with modern big tech companies where RSU growth can fuel a big chunk of your salary costs for your tech department when your company is on the rise, but scare everyone off when the reverse is true.
Even the Medallion Fund only averages 20-40% gains a year and they've stacked the deck with every possible advantage of resources and the most brilliant folks they can find. If the risk management on this is geared to the point where it's seeing 300% account volatility in a month, even in a positive direction, it's easier assign higher likelihood to
"this algo is levered far higher than it ought to be and while you've dodged landmines this month, you won't in the long run,"
vs.
"your 'minimum viable stat arb' and competent implementation outperforms the best-of-the-best outlier."
I think skepticism is warranted as most people at this point end up blowing up, but hey, I guess there's some slim possibility that it's the latter?
>Even the Medallion Fund only averages 20-40% gains a year and they've stacked the deck with every possible advantage of resources and the most brilliant folks they can find.
The Medallion Fund is also larger than a single quant's trading portfolio. This is important because a given trading strategy loses its effectiveness (in percentage terms) when scaled up. A strategy that yields 100% return on a 10k investment is unlikely to return 100% on a $10M investment, for instance.
Indeed they do, the "City of Everett". You can walk around inside. Boeing used it as a test bed for various experiments. The Museum of Flight is really a gem.
Boeing used to offer tours of the 747 factory. It's immense. I wonder if they're spinning up a different manufacturing line in that building?
South of Portland is the evergreen air and space museum. They have the spruce goose in there, it's huge. The water park next door has an old 747 mounted on the roof, and I'd the start of 6 water slides.
According to Wikipedia (https://en.wikipedia.org/wiki/Boeing_Everett_Factory#Current...), they are left with just the 767 (currently only available as a cargo or military tanker plane) and 777. 787 production was moved completely to the (non-unionized and reputedly lower-quality) South Carolina plant in 2021.
If I recall correctly, that building was so vast that they had trouble controlling the weather inside on a few occasions. Trouble as in, clouds were forming and rain was falling.
May that's just myth, but I like that myth enough to not google it.
