• 10_0@lemmy.ml
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    8 hours ago

    See how did sharks swim north without the north being there?

  • woodenghost [comrade/them]@hexbear.net
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    10 hours ago

    I just checked, Polaris is about ten times younger than sharks. The other two stars of its ternary star system are older, but not visible to the naked eye, so early sharks would not have been able to use them for purposes of navigation.

  • essteeyou@lemmy.world
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    17 hours ago

    Polaris is 45-67 million years old.

    The oldest total-group chondrichthyans, known as acanthodians or “spiny sharks”, appeared during the Early Silurian, around 439 million years ago.

    It’s not even close.

    • toynbee@lemmy.world
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      10 hours ago

      I came here to question whether that claim is true, saw your post, and thought something like “well, that settles that.” Then I scrolled down and saw neatchee’s (great username) post and now my whole world is uncertain.

        • mkwt@lemmy.world
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          14 hours ago

          Polaris goes in and out of North Star status on the 26,000 year precession cycle. So for the duration of humanity (let’s say 100,000 years), there have been decent chunks of time where it’s not in use.

          • sorrybookbroke
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            10 hours ago

            You gotta rest up man, that’s a pretty big job for one star

            • FuglyDuck@lemmy.world
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              10 hours ago

              Can you imagine having to give directions to a bunch of illiterate primates? Ugg. I’d have quite after the first thousand years.

            • Tar_Alcaran
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              9 hours ago

              They trade off. There are other stars that make for good pole star candidates

        • ZeffSyde@lemmy.world
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          5 hours ago

          Eh, they got to see the thousands of other stars that are now obscured by light/atmospheric pollution.

  • neatchee@lemmy.world
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    17 hours ago

    This is only sort of true, unfortunately. Polaris is a two-star system: Polaris Aa and Polaris B.

    Polaris B is much older than sharks, by several billion years.

    Polaris Aa appears to be younger than sharks, at a measley 50 million years old, compared to sharks’ 420 million years

    HOWEVER it is unclear whether Polaris Aa is actually that young. Scientists believe that, based on some contradictory findings, that measurement may be inaccurate if Polaris Aa is formed from two different stars that merged. In that scenario, the model we use to calculate star age would no longer work and could give wildly inaccurate estimates of the star’s true age

    TMYK

  • akilou
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    17 hours ago

    One of my favorites is “the Appalachian mountains are older than bones”

      • bss03@infosec.pub
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        12 hours ago

        Bones evolved for the first time: “485 Ma First vertebrates with true bones (jawless fishes)” – https://en.wikipedia.org/wiki/Timeline_of_the_evolutionary_history_of_life (Vertebrates existed without a bony notochord before then.)

        But the Appalachians were started much earlier: “The geologic processes that led to the formation of the Appalachian Mountains started 1.1 billion years ago.” They were basically finished growing by the time bones existed: “Around 480 million years ago, geologic processes began that led to three distinct orogenic eras that created much of the surface structure seen in today’s Appalachians. [d] During this period, mountains once reached elevations similar to those of the Alps and the Rockies” Since then, it’s just been wearing down. – https://en.wikipedia.org/wiki/Appalachian_Mountains