Interested in weather, meteorology and photography. Aviation weather observer.

Other account: @Deme@sopuli.xyz

  • 2 Posts
  • 20 Comments
Joined 2 years ago
cake
Cake day: July 5th, 2023

help-circle
rss
  • An extreme value is always only extreme in relation to some baseline. For temperatures it’s usually a value that departs far from the local average. With WBT it can also mean values that approach the limit of what the human physiology can handle, a value that is quite universal due to us all being of the same species. The body cannot adapt beyond the limits set by thermodynamics.

    Tropical and extreme aren’t mutually exclusive. +30°C in Antarctica would be both tropical and extreme. Both are used where applicable. A temperature can also be extreme without being tropical. No matter what Trump thinks, he doesn’t have the power to redefine (let alone erase) words.

    The wet bulb temp. in a proper sauna should get quite high, I don’t have exact numbers but above 70°C or so (dry temp. 90°C, relative humidity 50% would translate to a WBT of 74°C). In most contexts that would be extreme, but not here.


  • *Extreme WBT’s

    A wet bulb thermometer measures wet bulb temperature (WBT), which is a metric that always exists and can always be measured. It only gets bad when the WBT reaches an extreme value, as is the case for basically all environmental metrics. Saying that wet bulb temperature is lethal is like saying that temperature is lethal. Look out for temperature! I’m sorry for the rant so I’ll try to keep this short, but “wet bulb” by itself in this context is an inane shorthand that lacks all the significant words and muddles the meaning of those words that are in it. Scientists talk about Extreme WBT events, because that’s what they are. A less of a mouthful would be nice for science communication, but I don’t want it to come at the expense of words losing meaning like that.

    Heatwave is a nice and descriptive word for one type of an extreme temperature event. Cold snap is another one. I’m glad neither is called “temperature event” because that would be dumb.






  • The notations can be confusing, especially around noon and midnight. Is midnight am or pm when it’s equally distant to both the previous and the next noon? Why does 12am not follow 11am???

    Where I live we use 12hr time in casual spoken language but pretty much always specify the time of day as well, like eight in the evening or twelve at midnight. But for anything written or even remotely formal, 24h time is used for obvious reasons.


  • Sure, but the vast majority of people live in low lying areas and even then it doesn’t shift that drastically. You need to climb a mountain to see the difference when it comes to applications of daily life.

    Although now that I think about it. The same criticism applies to pretty much every definition of temperature that is based on the behaviour of matter. This also applies to Kelvin. Temperature is a property of matter and every type of matter behaves differently.


  • The thing to remember is that air is a great insulator. Air at 100°C isn’t nearly as bad as say water or metal at the same temperature against the skin. In fact, the air that comes in contact with the comparatively cold human skin will cool down rapidly, forming a layer of cooler air around you and lessening the sensation of heat further.





  • The headline is clickbait since you don’t even need to get past the paywall to see that “The website does not appear to be linked to Hamas”. That domain is registered under Wix.Com Ltd., an Israeli software company. There is no hacking involved here, just an Israeli site masquerading as a Hamas site gloating with attrocities.

    I think that this is part of a propaganda effort by Israel to capitalize on the October 7th attacks by maximising the emotional response from it. It’s all in English, so clearly directed at western audiences. It’s also quite on the nose with the caricaturistic portrayal of evil terrorist baby killers who do not understand PR.

    If an actual Hamas site was hacked by Israelis, I’d expect the hackers to flaunt their victory by posting something the islamists clearly wouldn’t (like idk pictures of bacon, a woman’s ankles or maybe some dudes kissing).

    As for an actual Hamas site, I’d expect a lot less displays of gore caused by Hamas and a lot more displays of gore caused by the IDF.





  • I have my doubts about that stealth. If it were just the tungsten rod by itself, it could well be coated in black, but the impulse needed to drop a massive projectile out of an orbit (and furthermore into a trajectory that impacts at the target) necessitates a relatively hefty maneuvering unit and that has to radiate heat to be kept operational. Cheaping out on the propulsion could be very costly because a failure in the middle of the deorbit burn would result in the rod coming down in a place you don’t want it to.

    The only way to hide it would be with decoys, which are already used by ICBM’s. Unlike ICBM’s, an orbital platform would need those decoys well before it’s used because there’s no terrain to hide in. A ballistic missile sub is very hard to track, satellites, not so much.

    About countermeasures: Becuse the rod can’t move by itself, it’s stuck on a fixed trajectory after the propulsion stage is discarded. This makes it an easy target for an interceptor missile. You already know where to look so the stealthy rod isn’t that hard to find, and then you just have to collide with it. And because the rod is coming down from MEO at the very least, you have ample time to do all this. An impact at such speeds would disintigrate anything and the rod isn’t an exception. At the very least it would fracture into multiple less aerodynamic pieces that do much less damage than the sum of their parts.


  • Gravity is not your friend. Getting stuff into LEO is still expensive af. A kinetic projectile dropped from space might have the same energy as a nuke, but it’s still going to be a lot more expensive. Additionally, you don’t have options on how that energy is released. It’s going into the ground and that’s that. A nuke (or any other explosive device for that matter) on the other hand can be detonated at a chosen altitude, or as a bunker buster if that’s what you want.

    The heavier the object, the more it’s going to take to push it out of that orbit. If your weapon system is in LEO, you can realistically only drop a rod on a small envelope along the future trajectory of the weapon system. Polar orbits would have the best coverage, but fly over a target outside of polar regions only twice a day. In order to get a wider range of firing solutions, the projectile needs considerable deltaV for orbital changes. And again, gravity fucks you over here because deep within Earth’s gravity well, changing the orbit of a massive tungsten rod takes a lot of fuel. Higher up these deltaV costs wouldn’t be as prohibitive and you’d have more options for using the weapon, but that would increase the time from launch to impact into the regieme of hours, way too slow for anything.

    The best solution would be to have a huge amount of rods in different orbits (akin to the spacejunk that is Starlink) to maximize the chances of at least one being able to fire on a target at any given place at any given time, but because those rods are still heavy af, such a plan is completely unfeasable.

    Rods from gods will never happen, at least not around Earth.



  • Skynet theories aside, the whole “AI will solve trafic” thing is just dumb. Sure, I suppose we could one day perfect a system of cars working as a hivemind to optimize the flow of trafic, but that just makes it impossible for anyone not part in that hivemind (cyclists etc.) to use the road.

    I suppose the “just one more lane bro” joke sort of applies here in that the problem caused by cars would be “solved” by doubling down on cars.



  • Hey guys, Peter Griffin here to explain the joke the image.

    The image taken in Yunnan (China) 16 Aug 2022 by JiaQi Sun displays a Cumulonimbus calvus with the accessory cloud pileus on top. A pileus is formed when a rising cloud pushes the air above it higher which causes it to cool down adiabatically. When sufficient humidity is present in that higher layer of air, the humidity condenses into a pileus.

    Here the pileus displays quite magnificent iridescence. The sun is behind the cloud. When sunlight passes through the very small and evenly sized cloud droplets of the pileus, diffraction takes place. Different wavelengths are diffracted in different angles and thus the white light of the sun is broken down into separate colours. While the cloud droplets are similar in size, there is still some variation there. The size of the droplets also affects the ammount of diffraction and thus the colours are somewhat disordered.

    If you want to see cloud iridescence yourself, look for clouds passing in front of the sun that aren’t opaque enough to block it completely. Lenticular clouds, Cirrocumulus lenticularis in particluar are good candidates for iridescence as they are formed in a similar manner to the pileus here and have an even distribution in droplet size.

    There have been a number of viral photoshops circulating the internet since the original pictures were taken where the cloud has been added to wide angle shots and made to appear like it takes up half the sky. These however are easily debunked with basic knowledge about clouds and the optical phenomena in question as the colours here are impossible at wider angles.