• essteeyou@lemmy.world
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    1 month 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.

      • i_stole_ur_taco
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        1 month ago

        They probably died off because they couldn’t use Polaris for navigation!

        • mkwt@lemmy.world
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          1 month 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.

        • ZeffSyde@lemmy.world
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          1 month ago

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

    • toynbee@lemmy.world
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      1 month 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.

  • neatchee@lemmy.world
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    1 month 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

    • Optional@lemmy.world
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      1 month ago

      Right but how did it know to be the pole star?? Huh?

      Yeah! Makes ya think!

    • davidgro@lemmy.world
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      1 month ago

      In my opinion Polaris B and Polaris Ab (it’s actually a three star system!) don’t count as ‘The North Star’ because they contribute almost nothing to the visible light seen without a telescope. Without Aa there’s just no north pole star at the moment.

      But that’s interesting about the age being uncertain. I’d use the age of the merger as the age of the star anyway unless it didn’t add much mass (but in that case it would have been a short lived giant anyway…) which would still likely put it under the 420 million years mark.

      • neatchee@lemmy.world
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        1 month ago

        Fair enough on the first point!

        The interesting scenario re: Polaris A’s age would be if a larger, younger original star merged with a smaller, much older star. You’d have a small amount of late-stage byproducts in an otherwise relatively early-stage star. That would definitely make any age models ‘confused’ heh

        I could imagine a scenario where the math works out such that the star appears a lot younger than it is despite being the product of a merger of two older stars, based on the masses and ages of the contributing objects and the amount of different material contributed by each

  • falsemirror@beehaw.org
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    1 month ago

    Unfortunately (or fortunately?) this appears to be untrue.

    Polaris is a cluster of stars formed about 2 billion years ago. Sharks originated about 450 million years ago.

    One star of Polaris (Aa) appears to be 50 million years old, but it seems likely due to a collision of stars which added mass to it.

  • 10_0@lemmy.ml
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    1 month ago

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