15 votes

Venus is not Earth's Closest Neighbour

8 comments

  1. [3]
    aphoenix (edited ) Link
    I thought this was a delightful non-obvious result of some (not-really applicable to anything) applied mathematics. Earth's closest planetary neighbour based on the average distance away is...

    I thought this was a delightful non-obvious result of some (not-really applicable to anything) applied mathematics.

    Earth's closest planetary neighbour based on the average distance away is actually Mercury, and in fact Mercury is the closest neighbour, by average distance, to every other planet.

    6 votes
    1. Spel Link Parent
      This came up recently on BBC’s More or Less podcast too and I definitely think it’s a pretty funny thing. It just seems to be so different from how we think about space.

      This came up recently on BBC’s More or Less podcast too and I definitely think it’s a pretty funny thing. It just seems to be so different from how we think about space.

      3 votes
    2. retiredrugger Link Parent
      That's something that I had never considered before, and it tripped me out haha

      That's something that I had never considered before, and it tripped me out haha

  2. [5]
    onyxleopard (edited ) Link
    If you start changing the definitions of your metrics, you should expect different results. Like, if I start changing the definition of who the richest person in the world is by measuring total...

    As it turns out, by some phenomenon of carelessness, ambiguity, or groupthink, science popularizers have disseminated information based on a flawed assumption about the average distance between planets. Using a mathematical method that we devised, we determine that when averaged over time, Earth’s nearest neighbor is in fact Mercury.

    If you start changing the definitions of your metrics, you should expect different results. Like, if I start changing the definition of who the richest person in the world is by measuring total square footage of land they own, or total liquid assets, instead of the total of all of their assets, I assume the richest person by those different metrics are not the same (or at least the relative ordering of all persons is not the same).

    While the math is neat, I don’t think the explanation of the motivation for which metric is better was sufficient. I understand the two metrics presented are different, but explaining why one metric is better than another (or why they are merely different but equal) is basically the most important thing a scientist needs to do when speaking to a lay audience. I guess, from my lay perspective, I don’t really care, probabilistically, which planet is closest to which other. So, if you tell me that Mercury is the closest planet to all other planets according to this metric, I’ll accept it, but I don’t really see how that is useful (other than as a piece of trivia—same as the naive metric of considering the difference in radii of orbits).

    What is the flaw in the popular, naive method? That it doesn’t agree with this newly proposed metric? That is not a flaw! That is just a difference. You need to make a better case for why your metric is superior other than it’s different, newer, and requires integration.

    3 votes
    1. [4]
      aphoenix Link Parent
      I think you're overthinking it. I read that as a tongue in cheek poke at common knowledge. I don't think they're actually proposing that we teach that the order of plants have changed; it's more...

      I think you're overthinking it. I read that as a tongue in cheek poke at common knowledge.

      I don't think they're actually proposing that we teach that the order of plants have changed; it's more an interesting discovery of how close we are, on average, to another planet.

      4 votes
      1. [3]
        onyxleopard Link Parent
        I know you’re not trying to attack me, but I really take offense at this. I didn’t overthink this. I merely thought about it critically. I expect the content on here to be thoughtful, and to stand...

        I think you're overthinking it.

        I know you’re not trying to attack me, but I really take offense at this. I didn’t overthink this. I merely thought about it critically. I expect the content on here to be thoughtful, and to stand up to critical thought from readers. I can get mindless fluff most places on the web—I come here with higher expectations.

        2 votes
        1. [2]
          aphoenix Link Parent
          This is intended as merely an item of mathematical interest, not as a sweeping revision of planetary education. I would argue that this is pretty close to an example of pure mathematics, not...

          This is intended as merely an item of mathematical interest, not as a sweeping revision of planetary education. I would argue that this is pretty close to an example of pure mathematics, not applied physics, and I would also argue that pure mathematics is not "mindless fluff". I don't want to put words in your mouth, so I'll simply ask: are you saying that Mathematics that isn't applied is "mindless fluff"? To me, it's the most mindful fluff around.

          3 votes
          1. onyxleopard Link Parent
            It’s presented in the domain of astrophysics, though, not pure math. I have no qualms with presenting math. My issue was with the article taking the position that they were correcting some...

            It’s presented in the domain of astrophysics, though, not pure math. I have no qualms with presenting math. My issue was with the article taking the position that they were correcting some long-standing problem. If they just framed it as, “here’s a novel way of computing the distances between planets”, that would be fine. Instead they editorialize it in a way that took a strong position which is not backed up at all (maybe there is a way to back it up, but they didn’t present it). That’s my issue. The math, and the explanation, I agree, is neat. The presentation is problematic.