• hayk@lemmy.ml
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    6 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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      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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        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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          6 days 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.

  • BurnedDonutHole@ani.social
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    6 days ago

    Modern physics is full of assumptions and placeholders for the generally accepted theories to work such the dark matter, dark energy, the inflation field, quantum gravity and gravitons etc… We don’t really know what they are, they are basically mathematical requirements for the currently accepted theories to work.

    • Tattorack@lemmy.world
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      6 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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        6 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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      8 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.

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        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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        8 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?

    • Deconceptualist@leminal.space
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      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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        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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        8 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.

    • SaraTonin@lemmy.world
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      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

      • Tattorack@lemmy.world
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        6 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.

  • ryathal@sh.itjust.works
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    8 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.

    • toddestan@lemmy.world
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      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.

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      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.

      • iamthetot@piefed.ca
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        8 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.

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        8 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.

  • Deconceptualist@leminal.space
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    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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      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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        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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      8 days ago

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

    • fizzle@quokk.au
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      The word “exosphere” was proposed by Lyman Spitzer to designate the outer part of a planetary atmosphere, defined as the region where the density is low enough to describe it as a collisionless region. Since the beginning of the space era, it was discovered that the major neutral constituent of Earth’s exosphere is atomic hydrogen, and Shklovsky (1959) coined the word “geocorona” to designate the H component of the exosphere.

      I didn’t read the whole paper obviously but this part makes it sound like you’re talking about the exosphere in which, by definition, there might be more gas molecules than elsewhere but few enough that they’re unlikely to run into them, or they’re unlikely to run into each other maybe IDK.

      Obviously, if there was a significant atmosphere the moon would experience atmospheric drag and would fall to earth.

      • mnemonicmonkeys@sh.itjust.works
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        8 days ago

        Obviously, if there was a significant atmosphere the moon would experience atmospheric drag and would fall to earth.

        Would it?

        The Moon is slowly drifting further away because Earth’s rotation is significantly faster than the lunar orbit. Some of Earth’s rotational energy is bled into the lunar orbit, causing it to increase in height, which in turn lowers its orbital period.

        If there was a significant atmosphere for Earth at that height, you’d think it would actually give the Moon a boost

    • amino@lemmy.blahaj.zone
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      also men aren’t inherently stronger than women. the sex segregation in sports is purely sectarian

      • Ada@piefed.blahaj.zone
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        It depends what you mean. Testosterone makes a difference. It improves blood oxygen levels and cardio capacity, and it increases strength (it’s a steroid).

        And depending on the context, the difference is larger. Men tend to have stronger hand grip than women for example, to the extent, there is very little overlap. But if you look at leg strength, the distributions are different, but they overlap significantly. And when you start to look at things like long distance endurance events, the distributions are even closer.

        However, none of those things align with “men” or “women”. They align with “the dominant sex hormone in your body”, and your capacity shifts as your sex hormones shift.

      • makingStuffForFun@lemmy.ml
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        That is an interesting one.

        I recall many years a group arm wrestle competition we all got into.

        Men and women, we were all having fun.

        Without exception, every single guy beat every single woman. And usually easily.

        I’m genuinely surprised by your statement.

        I also do pilates regularly. I’m a pretty avg size guy. I’m higher in strength setups (springs, angles, etc) than nearly everyone there, except the other men.

        Where are you seeing what you’re describing?

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          7 days ago

          It’s almost like cultural factors discourage most women from growing muscle, but encourages men to gain muscles

          But that would be impossible

          • makingStuffForFun@lemmy.ml
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            6 days ago

            I would say the women in my class are incredibly strong. They have excellent muscle development, and compared to non fitness folk, are almost intimidating.

            But, by and large, they’re not as strong as the men in the class for raw power.

            • gwl [he/him]@lemmy.blahaj.zone
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              The maximum output of a person with testosterone is higher, but funnily enough going on MtF HRT one of the main focus is to reduce the levels of testosterone, in fact in most tests trans MtF athletes have lower T levels than cis female athletes

  • AnBee@lemmy.blahaj.zone
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    If you get methanol poisoning for example from badly made liquor then the remedy for that is to drink ethanol (good liquor).

  • Snot Flickerman@lemmy.blahaj.zone
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    Trigger Warning: Existential Crisis

    spoiler

    Everything about us is young in the context of the wider universe. Human society, the human species, the planet earth, our solar system, our sun. We live near the dawn of creation, even though our universe feels unimaginably old compared to our brief lives. As the skies darken and all the stars burn out, that will take course over a time period longer than our individual solar system will last. When the last light goes out, time doesn’t stop, no the universe goes on and there’s an even longer period of endless empty inky blackness, the deep void. In the end, the universe may spend significantly more time as an endless dead void than it ever did as a universe with hope of life and at least one planet with confirmed organic life. There is no escaping it, and there is probably no way for our species to even survive and adapt to that era as it is.

    • Davel23@fedia.io
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      One of the possible answers to the Fermi Paradox is simply we’re the first.

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        We could be the great scourge of this part of the universe. Expanding recklessly through galaxies in the local group, leaving only the dead husks of stars that have been stripped of all usable energy. The exponential nature of scientific discovery means that not only do we have a head start, our head start compounds as time progresses. We become a horrific but very efficient war machine for the sole purpose of controlling and exploiting all available forms of energy for profit. We seem like we’re on that path.

      • Corporal_Punishment@feddit.uk
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        To be fair its likely to be the most probable answer.

        Whilst intelligent life is probably quite common at specific points in time, it isnt common at the same time, and if it is the distances involved are so vast it means we will never know they exist.

        The best we can hope for in all likelihood is that we stumble on the ruins of some other species that died out millions of years ago.

        Or we stumble on a bunch of blue monkeys who are as intelligent as dogs, but in 50 million years they will be the ones finding the ruins of our civilisation.

        • socsa@piefed.social
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          The flip side of this is that black hole entropy farming could keep simulated human consciousness alive for billions of years orbiting just outside the event horizon as we transition into the early stages of heat death, meaning that if this is possible, the statistically overwhelming portion of all human consciousness will exist in this state, making it a near statistic certainty that is what you are currently experiencing.

        • Don_alForno@feddit.org
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          but in 50 million years they will be the ones finding the ruins of our civilisation.

          Not if they have the misfortune to be found by us they wont.

      • Ada@piefed.blahaj.zone
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        That’s not an answer, because if life is common, then the chance of us being the first is minuscule.

        Lets say that life can only form around main sequence G type stars (ie, like our sun). There is no reason to believe this is true, but lets say it is for this example. The universe is 14 billion years old, and the sun is 4.5 billion years old. Lets round it to 4 billion years old when life first formed.

        Now, the earliest G type stars formed approximately 1 billion years after the universe formed. Lets say that life can only develop when those stars were at least 4 billion years old. That puts the earliest possible scenario where life formed at 5 billion years after the universe formed, and that was 9 billion years ago. Low balling it, there are approximately 7 billion g type main sequence stars current in our galaxy.

        All together, that means the chance of us simply being the first is very low, and if we are the first, then life isn’t common, and if life isn’t common, the underlying reason for that is the answer to the fermi paradox.

      • mnemonicmonkeys@sh.itjust.works
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        And it’s the most likely solution. The universe has been hostile to life until very recently (on a cosmological scale). We know we’re rather early in the goldilocks zone of universal habitability.

        I just find it odd when some people argue “humans aren’t special enough to be that lucky. We’re too stupid to achieve more”. It’s odd because calling humans stupid is actually arguing that humans are exceptional. Meanwhile you don’t have to be exceptional to be lucky.

        And if you’re wondering, it’s Lex Friedman that argues this. And no, I don’t listen to him anymore. I stopped once over 50% of the people he interviewed were just AI and crypto shills

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      A friend asked me if I’d have the option to live forever, would I? No; I don’t want to spend eternity floating around the galaxy.

  • Sanctus@anarchist.nexus
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    If you rub two creatures together just right you get another creature of mostly the same type a little bit later.

      • socsa@piefed.social
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        6 days ago

        Hey guys, did you know that in terms of male human and female Pokémon breeding, Vaporeon is the most compatible Pokémon for humans? Not only are they in the field egg group, which is mostly comprised of mammals, Vaporeon are an average of 3”03’ tall and 63.9 pounds, this means they’re large enough to be able handle human dicks, and with their impressive Base Stats for HP and access to Acid Armor, you can be rough with one. Due to their mostly water based biology, there’s no doubt in my mind that an aroused Vaporeon would be incredibly wet, so wet that you could easily have sex with one for hours without getting sore. They can also learn the moves Attract, Baby-Doll Eyes, Captivate, Charm, and Tail Whip, along with not having fur to hide nipples, so it’d be incredibly easy for one to get you in the mood. With their abilities Water Absorb and Hydration, they can easily recover from fatigue with enough water. No other Pokémon comes close to this level of compatibility. Also, fun fact, if you pull out enough, you can make your Vaporeon turn white. Vaporeon is literally built for human dick. Ungodly defense stat+high HP pool+Acid Armor means it can take cock all day, all shapes and sizes and still come for more