• hayk@lemmy.ml
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    2 days ago

    traveling back in time is not mathematically disallowed by the general relativity.

    in fact there is a lot of work done on the topic, and lots of potential scenarios proposed (which usually involve describing the space-time warped into weird 4D shapes). what GR does tell you is what kind of matter/energy would produce such spaces (since in GR these two are intertwined), and that’s kind of where common sense works again: most proposed geometries do require either negative energy densities or mathematical singularities (which to be fair are not impossible, but we kinda never seen that, aside from dark energy).

    on the other hand – faster-than-light travel is also possible – albeit with similar constraints.

    • UnderpantsWeevil@lemmy.world
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      2 days ago

      traveling back in time is not mathematically disallowed by the general relativity.

      Moving mass backwards through time isn’t strictly mathematically disallowed. Idk what it’s going to look like when it arrives, though.

      What does a Tachyon even look like?

      • hayk@lemmy.ml
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        2 days ago

        i didn’t mean purely mathematically. but from the physics standpoint. in other words, if you provide enough dark energy and shape it into a specific configuration, it will generate space-time where time travel is possible in practice.

        • UnderpantsWeevil@lemmy.world
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          1 day ago

          if you provide enough dark energy

          “How much ya got?”

          “Well, it’s a purely theoretical substance. But theoretically we’ve got more of that than all the regular energy in the known universe.”

          and shape it into a specific configuration

          I want to say that’ll be the easy part, but I guess it really depends how abstract of a shape we’re talking about and how malleable dark energy ends up being.

  • kyonshi@piefed.social
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    3 days ago

    Every single one of us is travelling through space on a tiny speck of dirt, circling a permanent explosion that doesn’t know how to stop itself at 30km/s.
    That explosion and multiple specks of dirt besides our own dance around the center of the galaxy in a complex ballet with 200 billion other permanently exploding balls of fire and plasma, many of which are sizeably larger than ours and also have collected pieces of dirt circling around them, at a speed of 200km/s. The center of this agglomeration of giant balls of fire and dirt is a… thing… that is in itself so massive it can’t help eating everything that comes near including suns, light, and the concept of time.

    And there, travelling around the center of the galaxy at 200km/s, spiraling around your sun at 30km/s, there is you. And somehow you have to work tomorrow.

  • village604@adultswim.fan
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    3 days ago

    Bloodletting is still a legitimate medical treatment, now called therapeutic phlebotomy.

    Some medicines, like testosterone, can increase your hemoglobin or blood count, so donating blood is the fix for it.

    • stringere@sh.itjust.works
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      3 days ago

      Hemochromatosis, too. Body doesn’t eliminate iron so it can build up in organs, notably liver and kidneys.

      The treatment is bloodletting. My wife wanted to get leeches. I settled for just donating 32 times in the first year after finding out. My ferritin count was 9 times the usual max for a man my age. My gallbladder fluid was carrying iron. I was Iron Man.

    • Anivia@feddit.org
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      3 days ago

      Testosterone, even when taken at supraphysiologic dosages, rarely causes erythrocytosis to an extent that therapeutic phlebotomy is necessary.

      Other anabolic steroids, particularly Equipoise (aka Boldenone), increase red blood cell count significantly more than testosterone.

    • Tattorack@lemmy.world
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      2 days ago

      CORRECTION!!

      “Shark” is not a species. A whaleshark is a species. A tigershark is a species. “Shark”, representing multiple species of shark, is a division, specifically the Selachii division.

      The Selachii division is 200 million years old. One galactic year for Sol is 225 million years old. This means that sharks, as we know them, have not existed as a division for two galactic years, barely even for one! Horshoe crabs have been around for 250 million years nearly completely unchanged by evolution, so they have been around for one galactic year… But nobody ever seems to talk about them…

      Officially, what came before sharks are classified as a different division with “shark-like morphology”, but they aren’t sharks.

      Sharks have existed for longer than the North Star, though. So there’s that.

      • Eufalconimorph@discuss.tchncs.de
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        2 days ago

        The oldest fossils known are stromatolite fossils from 3.48 billion years ago. There are living stromatolites today. They predate Earth having significant oxygen in its atmosphere, because the cyanobacteria that formed them created the oxygen gas through photosynthesis from carbon dioxide. They’ve orbited the galaxy over fifteen times.

    • Nibodhika@lemmy.world
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      4 days ago

      Sharks are so old that I’ve seen other comparisons, had never seen the milky way one before, that’s very interesting, the other ones I knew is that sharks are older than:

      • The rings of Saturn
      • Trees

      So when sharks first evolved Saturn had no rings and trees didn’t exist yet.

      • Deconceptualist@leminal.space
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        3 days ago

        Sharks also predate basically all big recognizable surface geology features on earth. They’re way older than the Grand Canyon or the Himalayas. It kind of makes sense once you realize they date back to the Pangea supercontinent.

        Also, biologically modern humans are much older than Niagara Falls.

      • TheRealKuni@piefed.social
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        3 days ago

        when sharks first evolved Saturn had no rings

        Or at least, didn’t have its current rings. I could be wrong but couldn’t it have torn apart other moons to create a different set of rings that then degraded over time?

    • SaraTonin@lemmy.world
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      3 days ago

      Worth pointing out that this is the shark lineage and not modern sharks. Sharks have evolved a lot over the last several hundred million years

      In the same sense, jellyfish are older than sharks, and sponges are the oldest still-extant animal lineage. Or just sounds cooler to say sharks

    • Deconceptualist@leminal.space
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      3 days ago

      I don’t understand the clock one.

      The shark fact is impressive though. I like to tell folks that the galaxy is so big that the solar system hasn’t even made 1/4 of an orbit since the non-avian dinosaurs went extinct. Might add some perspective.

      Nitpick: there are many species of shark so maybe you meant taxonomic genus or family.

      • gwl [he/him]@lemmy.blahaj.zone
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        2 days ago

        Well the specifics are the lineage which includes sharks, we found stuff that might be sharks but hard to prove are definitely sharks that’s 450 million years old (fossil sharklike scales)

        And, this is copypaste from Snopes:

        The earliest known fossil evidence of sharks (or their ancestors) are “shark-like scales” that date back to 450 million years ago, according to the National History Museum in London. However, whether these scales adorned “true sharks” or “shark-like animals” is an issue debated by the scientific community.

        Nonetheless, scientists largely agree that, according to DNA evidence, living sharks, rays, and deep-sea fish called chimeras likely began evolving around 420 million years ago.

      • aramis87@fedia.io
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        4 days ago

        I don’t understand the clock one.

        Part of the western Florida panhandle (WFP) is on Central time. Part of southeastern Oregon (SEO) is on Mountain time. That puts them one hour apart.

        In the fall, when we go back into Standard Time, when the clock hits 2am, you flip the clock back to 1am.

        So, during a normal night, WFP would be at 2am and SEO would be 1am. But on the night the time changes, WFP hits 2am and immediately flips their clocks back to 1am - which means that, for one hour a year (until SEO hits 2am and flips their clocks back), part of Florida and part of Oregon’s clocks are showing the exact same time.

        I kinda struggled over how to word this - they’re not in the same time zone, but for this one hour they might as well be.

      • Tattorack@lemmy.world
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        2 days ago

        Trees are 385 million years old. Sharks are 200 million years old. Trees still out-date sharks.

        Although… Trees have evolved multiple times in Earth’s history… So sharks are certainly older than certain trees. But not older than the whole tree concept thing.

  • AnBee@lemmy.blahaj.zone
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    3 days ago

    If you get methanol poisoning for example from badly made liquor then the remedy for that is to drink ethanol (good liquor).

  • Applesauce@lemmy.world
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    3 days ago

    There are more grains of sand on the planet Earth than there are stars in the solar system.

  • Deconceptualist@leminal.space
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    4 days ago

    If you’re not familiar with the flavors of quarks, they probably seem fake.

    • Up
    • Down
    • Top
    • Bottom
    • Charm
    • Strange

    Of course they all have antimatter counterparts. But anti-up is not the same as a down quark, anti-top is not the same as a bottom quark, etc.

    • Barbecue Cowboy@lemmy.dbzer0.com
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      3 days ago

      I do want to hear the story of the physicist when they got to making up the names for charm and just strange. I imagine many sleepless nights.

      • Deconceptualist@leminal.space
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        3 days ago

        The quark flavors were given their names for several reasons. The up and down quarks are named after the up and down components of isospin, which they carry.[60] Strange quarks were given their name because they were discovered to be components of the strange particles discovered in cosmic rays years before the quark model was proposed; these particles were deemed “strange” because they had unusually long lifetimes.[61] Glashow, who co-proposed the charm quark with Bjorken, is quoted as saying, “We called our construct the ‘charmed quark’, for we were fascinated and pleased by the symmetry it brought to the subnuclear world.”[62] The names “top” and “bottom”, coined by Harari, were chosen because they are “logical partners for up and down quarks”.[41][42][61] Alternative names for top and bottom quarks are “truth” and “beauty”,[nb 4] but these names have somewhat fallen out of use.[66] While “truth” never did catch on, accelerator complexes devoted to massive production of bottom quarks are sometimes called “beauty factories”.

        https://en.wikipedia.org/wiki/Quark

    • Tollana1234567@lemmy.today
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      4 days ago

      dont they also have a different SPin too, im not a physics geek, but i did take some remedial astronomy/physics courses.

  • ryathal@sh.itjust.works
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    4 days ago

    Some fun geography one’s.
    Maine is the closest US state to Africa.
    Alaska is the northern most, Western most, and Eastern most state in the US.

    • ilinamorato@lemmy.world
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      3 days ago

      My favorite geography fact is that, if you’re on the northern edge of Brazil, you’re actually closer to Canada than you are to the southern border of Brazil.

    • toddestan@lemmy.world
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      4 days ago

      My favorite geography one: You get on a plane at Tampa Bay, Florida and fly due south. Which South American countries do you fly over?

      Answer is none of them. You miss the entire continent because you are too far west.

      • iamthetot@piefed.ca
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        4 days ago

        For the Alaska one, the Aleutian Islands extend beyond the 180° line of longitude, placing the tip of them within the eastern hemisphere.

      • ryathal@sh.itjust.works
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        3 days ago

        The Alaska one North and West are obvious, but there are some islands that cross the date line, making them technically east.

        Someone else posted a graphic, but basically Maine is significantly farther east which cancels out the North/South difference of other states.

  • village604@adultswim.fan
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    3 days ago

    Ethanol can help protect your liver from the damage an acetaminophen overdose causes.

    You’d think that doubling up on liver harming substances would have an additive effect, but nope.

    • mic_check_one_two@lemmy.dbzer0.com
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      3 days ago

      Similarly, ethanol can help protect you from the poisonous effects of methanol (wood alcohol). Methanol by itself isn’t actually harmful, but it gets broken down into harmful byproducts that will make you go blind and then kill you.

      The enzyme responsible for breaking down methanol is also used to break down ethanol. And enzymes have a limited capacity for work. In other words, they can only break down a certain number of molecules at any given time. And the enzyme is more compatible with ethanol than methanol.

      So if you suspect someone drank methanol, (it is a common ingredient in antifreeze), you should have them start taking shots. Pump them full of as much liquor as possible, as quickly as possible. Get them absolutely shitfaced ASAP, and keep them wasted until they get to the hospital. It will prevent the vast majority of the methanol from being broken down, which will prevent the actual poisoning from happening.

      • village604@adultswim.fan
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        3 days ago

        It’s ethylene glycol that’s commonly in antifreeze, but ethanol protects against that too. I believe methanol is common in windshield wiper fluid, though.

          • sleepmode@lemmy.world
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            2 days ago

            Pretty much. Mazda had an issue with spiders attracted to gasoline clogging up fuel systems while being shipped overseas. And soy-based wire sheathing is apparently quite the delicacy to certain animals.

      • mnemonicmonkeys@sh.itjust.works
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        19 hours ago

        Active. Not immediately spewing lava, but they aren’t done.

        Also, there’s warm liquid water lakes underneath parts of the antarctic ice as well. And they’re caused by geothermal vents, not global warming

    • delgato@sh.itjust.works
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      3 days ago

      I like this fact and as a geologist I’m a little numb to facts about the Earth. At some level, all land on Earth has a volcanic origin by virtue of us having a molten core, a rigid mantle, and a crusty crust that seeps magma/lava. Time metamorphoses and sediments the rock in different ways. Antarctica just had the misfortune of migrating to the South Pole where millions of years of snow fall lead to its icy encapsulation.