TauZero

@TauZero@mander.xyz

• ⁨Comment⁩ on ⁨KM3-230213A⁩ ⁨⁨14⁩ ⁨hours⁩ ago⁩:

  KM3-230213A is an ultra-energetic (220PeV) neutrino event recorded by the Cubic Kilometre Neutrino Telescope (KM3NeT) on the bottom of the Mediterranean sea. The telescope consists of thousands of photomultiplier sensors suspended in the water, watching for Cherenkov radiation of the decay particles resulting from the rare collision of a neutrino with the inside of the Earth. There is no known cosmic mechanism how a neutrino so energetic could have come to be.

  This meme proposes the hijinks of Apu as an alternative explanation of how all those blue-sensitive photomultipliers got activated (saturated even) in a straight line going from bottom up all at once.

• ⁨Comment⁩ on ⁨Jigsaw Trolley Problem⁩ ⁨⁨1⁩ ⁨day⁩ ago⁩:

  Your family was kidnapped and is now safely eating ice cream backstage. Tied to the tracks are 5 infinite worlds Hitlers.

• ⁨Comment⁩ on ⁨Jigsaw Trolley Problem⁩ ⁨⁨1⁩ ⁨day⁩ ago⁩:

  it’s not clear that he’s following Monty Hall rules

  Whenever I see a badly-specified Monty Hall Problem, I always imagine the host saying something like “Oh, you want to pick door number 1? Well, guess what - the car was behind door number 3 all along! You get nothing but a goat!” And only when you initially pick a door with the car does the host ask “Are you sure you wouldn’t rather switch to door number 2? Look, there is even a goat behind door number 3!” Switching doors 100% gurantees you get a goat… or 50% silver balls in this case.

• ⁨Comment⁩ on ⁨Jigsaw Trolley Problem⁩ ⁨⁨1⁩ ⁨day⁩ ago⁩:

  Yeah, problem doesn’t specify whether you want your family to live. Common mistake.

• ⁨Comment⁩ on ⁨Jigsaw Trolley Problem⁩ ⁨⁨1⁩ ⁨day⁩ ago⁩:

  Doesn’t say it’s your family tied to the tracks either.

• ⁨Comment⁩ on ⁨Jigsaw Trolley Problem⁩ ⁨⁨1⁩ ⁨day⁩ ago⁩:

  Beautifully written!

  I think the probabilities cancel out?

  My conclusion as well. Except that since Jigsaw has taken one gold ball out, door 2 must have slightly better chance of gold ball remaining on average (75% vs 72.2%?).

• Jigsaw Trolley Problemmander.xyz ↗
  Submitted ⁨⁨1⁩ ⁨day⁩ ago⁩ to ⁨science_memes@mander.xyz⁩ | ⁨27⁩ ⁨comments⁩
• ⁨Comment⁩ on ⁨China begins assembling its supercomputer in space⁩ ⁨⁨5⁩ ⁨weeks⁩ ago⁩:

  Then you’d be surprised when you calculate the numbers!

  A Falcon 9 delivers 13100kg to LEO and has 395,700kg propellant in 1st stage and 92,670kg in 2nd stage. Propellant in both is LOX/RP-1. RP-1 is basically long chains of CH2, so together they burn as:

  3 O2 (3x32) + 2 CH2 (2x14) -> 2 CO2 (2x44) + 2 H2O (2x18)
  

  Which is 2*44/(2*44+2*18) = 71% CO2. Meaning each launch makes (395700+92670)*.71 = 347 tons CO2 or 347/13.1 = 26.5 tons of CO2 per ton to orbit. A lot of it is burned in space, but I’m guessing the exhaust gases don’t reach escape velocity so they all end up in the atmosphere anyway.

  As for how much a compute satellite weighs, there is a wider range of possibilities, since they don’t exist yet. This is China launching a test version of one, but it’s not yet an artifact optimized for compute per watt per kilogram that we’d imagine a supercomputer to be.

  I like to imagine something like a gaming PC strapped to a portable solar panel, a true cubesat :). On online shopping I currently see a fancy gaming PC at 12.7kg with 650W, and a 600W solar panel at 12.5kg. Strap them together with duct tape, and it’s 1000/(12.7+12.5)*600 = 24kW of compute power per ton to orbit.

  Something more real life is the ISS support truss. STS-119 delivered and installed S6 truss on the ISS. The 14,088kg payload included solar panels, batteries, and truss superstructure, supplying last 25% of station’s power, or 30kW. Say, double that to strap server-grade hardware and cooling on it. That’s 1000*30/(2*14088) = 1.1kW of compute per ton to orbit. A 500kg 1kW server is overkilling it, but we are being conservative here.

  In my past post I’ve calculated that fossil fuel electricity on Earth makes 296g CO2 per 1 kilowatthour (using gas turbine at 60% efficiency burning 891kJ/mol methane into 1 mol CO2: 1kJ/s * 3600s / 0.6 eff / (891kJ/mol) * 44g/mol = 296g, as is the case where I live).

  The CO2 payback time for a ton of duct taped gamer PC is 1000kg * 26.5kg CO2/kg / ( 24kW * 0.296kg/kW/hour) / (24*365) = 0.43 years. The CO2 payback time for a steel truss monstrosity is `1000kg * 26.5kg/kg / (1.1kW * 0.296kg/kW/hour) / (24*365) = 9.3 years.

  Hey, I was pretty close!

• ⁨Comment⁩ on ⁨China begins assembling its supercomputer in space⁩ ⁨⁨5⁩ ⁨weeks⁩ ago⁩:

  A solar-powered computer in space could recoup the CO2 cost of its launch fuel over its lifecycle (say 10 years?) when compared to coal-fueled electricity on the ground. After that it’s free. Of course, you’d benefit more by filling up every available spot on the ground with solar arrays first! But you will eventually run out, or you might not want to do that.

• ⁨Comment⁩ on ⁨China begins assembling its supercomputer in space⁩ ⁨⁨5⁩ ⁨weeks⁩ ago⁩:

  If you have a megawatt solar array, you can also afford a megawatt cooling array. The size is comparable.

• ⁨Comment⁩ on ⁨Why don't these code-writing AIs just output straight up machine code?⁩ ⁨⁨5⁩ ⁨weeks⁩ ago⁩:

  Only because it’s English and the model is already trained on a large corpus of English text, so it has some idea of what a “table row” is for example. It could learn the concept from reading assembly code from scratch, it would just take longer. Hell, even Lego bricks can be trained on! avalovelace1.github.io/LegoGPT/

  Our system tokenizes a LEGO design into a sequence of text tokens, ordered in a raster-scan manner from bottom to top. … At inference time, LegoGPT generates LEGO designs incrementally by predicting one brick at a time given a text prompt.

• ⁨Comment⁩ on ⁨Why don't these code-writing AIs just output straight up machine code?⁩ ⁨⁨5⁩ ⁨weeks⁩ ago⁩:

  Language is language. To an LLM, English is as good as Java is as good as machine code to train on. I like to imagine if we suddenly uncovered a library of books left over from ancient aliens, we could train an LLM on it (as long as the symbols themselves are legible), and it would generate stories in the alien language that would sound correct to the aliens, even though the alien world and alien life are completely unknown and incomprehensible to us.

• ⁨Comment⁩ on ⁨Me when I zoom past traffic on my e-scooter⁩ ⁨⁨1⁩ ⁨month⁩ ago⁩:

  sacrifice the luxury of convenience and being able to get doordash whenever you want

  Not necessary. I live in Manhattan and the street canyons are full of doordasher ebikes, and grocery store isles are jammed with instacarter trailer carts which they then hitch up to more ebikes.

• ⁨Comment⁩ on ⁨Me when I zoom past traffic on my e-scooter⁩ ⁨⁨1⁩ ⁨month⁩ ago⁩:

  otherwise empty bike lane

  Over here in New York, everyone got an e-bike and now we get bike jams in the bike lane during commute hour. Dunno how I should feel about it. Aladeen? :(: Still faster than a car for sure.

• ⁨Comment⁩ on ⁨At least 4,500 Americans per year die from hydroxyl acid exposure⁩ ⁨⁨1⁩ ⁨month⁩ ago⁩:

  I saw a study that DHMO is stored in the balls.

• ⁨Comment⁩ on ⁨Tethered Bottle Caps⁩ ⁨⁨11⁩ ⁨months⁩ ago⁩:

  Yeah, I concede that small caps are more likely to be carried away by rainwater than whole bottles :D. What I meant was that for every loose cap on the ground there is a bottle lying around somewhere, and also there are bottles with caps on. No one is tossing their cap into the bushes and then taking the bottle to the recycling center.

• ⁨Comment⁩ on ⁨Irresistible⁩ ⁨⁨11⁩ ⁨months⁩ ago⁩:

  Can you explain please, where I made a mistake?

  Your mistake is thinking Earth is 6km in radius! :D 6km is how far you walk in an hour. Either you think Earth 1000 times too small or kilometer 1000 times too big.

• ⁨Comment⁩ on ⁨Irresistible⁩ ⁨⁨11⁩ ⁨months⁩ ago⁩:

  For an object heavier than the Earth, 1g radius will be greater than the radius of Earth. For 56 Earth masses that’s sqrt(56) times bigger = 48000km.

  A 56 Earth mass black hole will take 5.5e55 years to evaporate according to this calculator. A 100kg black hole (more close to what Richard used to be) is much smaller than the nucleus of an atom and will evaporate in 0.05 nanoseconds.

  Curiously there was a paper recently that calculated that even if there was a small black hole in the center of the Sun, it would take millions of years for it to grow, because the aperture is so small not much can fit through, and the infalling gas heats up so much as to repel the rest, creating an internal hot bubble.

• ⁨Comment⁩ on ⁨Tethered Bottle Caps⁩ ⁨⁨11⁩ ⁨months⁩ ago⁩:

  I pick up street litter, and having picked up thousands of pounds, I have never felt that loose caps are a problem, let alone one that requires such a solution. The number of littered bottles, with or without a cap, is greater than the number of loose caps, and the amount of plastic in every bottle dwarfs the plastic in a cap. Fixing the cap to the bottle will do nothing to improve the recycling rate of plastic if entire bottles are already tossed anyway.

  I consider the idea of cap tethers as adversarial memetic warfare thrust upon us for some unknown ulterior purpose, possibly to make us hate the very idea of environmental consciousness. Same as paper straws. I like plastic bag bans though.

  As far as picking litter is concerned, I personally prefer finding bottles without a cap. At least those are empty, all liquid having evaporated after the bottle has spent several months in the bushes. The capped bottles are often half-full and are just nasty. (Who even pays for a bottle of drink and not drinks half of it anyway?)

• ⁨Comment⁩ on ⁨Trying to buy right size bicycle wheel online⁩ ⁨⁨1⁩ ⁨year⁩ ago⁩:

  This is a great gotcha! I just recently learned that 700C, the “29er”, and (some) “28 inch” are all the same wheel.

• ⁨Comment⁩ on ⁨Trying to buy right size bicycle wheel online⁩ ⁨⁨1⁩ ⁨year⁩ ago⁩:

  To be fair, when I was little I too was guessing that “C” stands for centimeters or something metric. Now I know that “C” in “700C”, the most popular road/hybrid wheel size, stands for the third size in the French “ABCD” notation, where sizes “700A”, “700B”, and “700D” are obsolete and are no longer manufactured.

• ⁨Comment⁩ on ⁨Trying to buy right size bicycle wheel online⁩ ⁨⁨1⁩ ⁨year⁩ ago⁩:

  I’d love to use ISO sizes, but even if I know that I need a 40-622 wheel, there is no way to search for it on the storefront if every single seller made gross mistakes in labeling their product! I have to ignore the specs shown entirely and make educated guesses based on title alone. For example “WHEEL AL 700 FRONT ALEX AP18 QR Silver UCP” in the picture is almost certainly a 700C wheel and NOT an 18-inch wheel. The “18” in the title probably stands for 18mm rim width, which means that this wheel will fit my bike and tire, but is a bit more narrow than ideal 23mm. The sellers must be copying the title verbatim from the manufacturer, and then haphazardly filling out the specifications without knowing or understanding the actual numbers. The ISO size is not mentioned at all.

• ⁨Comment⁩ on ⁨Trying to buy right size bicycle wheel online⁩ ⁨⁨1⁩ ⁨year⁩ ago⁩:

  I wanted to go with this, but had to go even bigger. The largest mine truck according to the wiki is BelAZ 75710 (as seen in the picture) which has “59/80R63” tires that are merely 402.7cm big.

• Trying to buy right size bicycle wheel onlinemander.xyz ↗
  Submitted ⁨⁨1⁩ ⁨year⁩ ago⁩ to ⁨mildlyinfuriating@lemmy.world⁩ | ⁨24⁩ ⁨comments⁩
• ⁨Comment⁩ on ⁨Weird 🤔⁩ ⁨⁨1⁩ ⁨year⁩ ago⁩:

  Oh I was well aware what community I was in 😁. I hate cars and exclusively ride bikes myself and here I was making a joke how I managed to get !fuck_cars of all places to downvote me for not watching fox news. All because my groupthink is not exactly identical to their groupthink (I am not the grandparent comment btw).

  The secret is that karma does not matter anywhere! However, as long as the comment sorting algorithm is the way it is, I will keep believing that the downvote button is for posts that are non-constructive contributions, not for disagreement. Burying discussion is not constructive, but that’s what the algorithm will do. Maybe this is a hopeless task, but I wish that after a conversation I have learned something new, or taught someone something, not just made myself feel better.

• ⁨Comment⁩ on ⁨First live birth of a chimeric monkey using embryonic stem cell lines⁩ ⁨⁨1⁩ ⁨year⁩ ago⁩:

  To be clear, human chimeras already exist naturally, from the fusion of twin embryos in utero. Most of them go entire lives without even realizing it. Only occasionally it pops up in the news when someone receives a negative paternity test and after lots of stress and hairpulling and doctor’s visits it turns out that their blood comes from a different cell line than their balls.

  Human-ape chimeras are the stuff of bioethicists’ nightmares and thankfully illegal everywhere civilized.

• ⁨Comment⁩ on ⁨Weird 🤔⁩ ⁨⁨1⁩ ⁨year⁩ ago⁩:

  Fox the broadcast TV channel is different from Fox News the cable channel. Broadcast TV is operated by one of ~100 local affiliates and shows the Simpsons and local news. Fox News Channel is the Murdoch personal project to produce 24-hour conservative propaganda to shift the national discourse. Or at least it was this way 20 years ago, haven’t seen what the TV branding looks like nowadays.

• ⁨Comment⁩ on ⁨Weird 🤔⁩ ⁨⁨1⁩ ⁨year⁩ ago⁩:

  My last comment got downvoted for saying I have never watched Fox news 🤷🏾.

• ⁨Comment⁩ on ⁨Panik⁩ ⁨⁨1⁩ ⁨year⁩ ago⁩:

  There is a mathematical algorithm that proves this works in all cases. However this rule is not actually all that impressive as it appears at first glance! The number of operations (comparisons/subtractions/multiplications) you need to do is equivalent to just long-dividing the number by 7.

  Consider: each operation of the rule removes one digit from the end. But you could just as easily apply the rule like “If the first digit is >=7, subtract 7 from it. Else, subtract the biggest multiple of 7 that will fit from the first two digits.” To skip multiplying, you can use the following jump table: if the first digit is 6, subtract 54 from the first 2 digits, if 5 subtract 49, if 4: 35, if 3: 28, if 2: 14, if 1: 07. That will also remove one digit from the front! But now you are just doing long division.

• ⁨Comment⁩ on ⁨[CW: Slurs] Any attempt to connect with my dad immediately turns into "Woke liberals are ruining the world."⁩ ⁨⁨1⁩ ⁨year⁩ ago⁩:

  Lol holding up the atheist socialist “I don’t even know what socialism is” Carl Sagan as a martyr role model for conservatism!