Comment on my kid is movin to AU

• Tenderizer@aussie.zone ⁨3⁩ ⁨weeks⁩ ago

  No, it’s not the angle. The sun’s orbit isn’t exactly symetrical, it’s a bit lopsided. In January the sun is about 5% closer to earth.

  In the Northern hemisphere this is during winter, so it’s the best of both worlds. In Australia though it’s the reverse. We get extra dim winters and extra bright summers.

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  • zero_gravitas@aussie.zone ⁨3⁩ ⁨weeks⁩ ago

    Ah, thank you for the clarification! I hadn’t realised that the eccentricity of Earth’s orbit made an appreciable difference, but apparently yeah, especially at the equator: journals.plos.org/climate/article?id=10.1371%2Fjo…

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    • TimePencil@infosec.exchange ⁨3⁩ ⁨weeks⁩ ago

      @zero_gravitas

      Appreciable difference? Not really. But a 'calculable' difference. Sure!

      Be sure to appreciate the HUGE difference of the landmasses in the northern and southern hemispheres.

      The primary way heat "gets into" our atmosphere is via re-radiation from the "ground".

      Compare the amount of "ground" between N45° and the North Pole, with that of the amount of "ocean" between S45° and the South Pole.

      At perihelion (around 4th Jan.) the southern hemisphere is in summertime, but the southern oceans easily absorb any extra solar energy by being 'a little bit closer to the sun'. It's roughly equivalent to having the energy used by an extra 5000 cars arrive as solar radiation... and for *most* of that solar energy be absorbed by the ocean.

      The tiny (almost insignificant) effect the earth's orbital eccentricity has on weather and climate is FAR less than that of our planet's axial tilt and the position of our continental land masses.

      But, sure, if some researchers wish to tweak the underlying data used for the Milankovitch cycles, then, fine.

      But our world is still on fire, and our children's future will be ashes unless we act now.

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      • zero_gravitas@aussie.zone ⁨3⁩ ⁨weeks⁩ ago

        The 7% difference in insolation between perihelion and ahelion (a figure I’ve seen mentioned in multiple places) seems like it would be significant for sunburn and skin cancer, at least at the population level.

        I found an ABC article that doesn’t specifically say the 7% figure, but mentions perihelion as a factor in 10% higher UV in Australia. It downplays the role that extra 10% plays in our melanoma rates, though, and I suppose that’s fair, I don’t think anyone’s getting caught out by burning 10% faster, because they would have gone inside 10% sooner if they had known, haha

        Together, Professor Whiteman says, these factors mean Australia’s UV is “probably about 10 per cent higher on average” than the equivalent latitude in the Northern Hemisphere.

        “That would mean for people living in Brisbane it is higher than for people living in Miami in the US, and for people in Melbourne, it’s higher than for people living in Athens, Greece.”

        While a 10 per cent increase in UV is significant, and might account for that sting in our summer sun, reasons for Australia’s high melanoma rates are more lifestyle-related, he says.

        source: www.abc.net.au/news/science/…/104870806

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  • TimePencil@infosec.exchange ⁨3⁩ ⁨weeks⁩ ago

    @Tenderizer

    Ummm...
    "No, it’s not the angle."
    Wrong. Axial tilt IS what causes our seasons, NOT the distance from the sun.

    Speaking of the sun, "The sun’s orbit isn’t exactly symetrical..."

    The sun's orbit? Around what? The centre of the Milky Way?

    @zero_gravitas

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    • Tenderizer@aussie.zone ⁨3⁩ ⁨weeks⁩ ago

      en.wikipedia.org/wiki/Apsis

      You’re not 100% wrong. Zero_gravitas answered my comment about the apsis with a comment about the seasons, and I called them wrong even though technically they were just referring to the wrong topic. I was right though, the perihelion occurs in January and the anhelion occurs in July, and that this means the sun is closer to earth during Australian summer than it is during American summer.

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