Sunday on Earth

WHEN IS A RAINBOW NOT A RAINBOW? At this time of year, a colorful arc often appears in the noontime sky. It looks like a rainbow, but it’s not. “I saw one on June 23rd while I was walking through forest near Flagstaff, Arizona,” reports David Blanchard, who took this picture through the treetops:

1a

Blanchard witnessed a circumhorizon arc–a rainbow-colored band of light caused by the sun shining through plate-shaped ice crystals floating in cirrus clouds. Actual rainbows, on the other hand, are caused by sunlight reflected from raindrops.

Summer is the season for circumhorizontal arcs because they appear only when the sun is high in the sky–more than 58o above the horizon. The arc’s enormous size and pure spectral colors make it one of the most beautiful of all ice halos.

At medium latitudes, like much of the USA, the arc is not rare.Typically, it can be seen several times each summer. In contrast, further north in much of Europe the circumhorizon arc is a rarity and impossible to see north of Copenhagen. See the charts in Les Cowley’s web page ‘How rare?’ for the visibility at your location.

@ SPACEWEATHER.com

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About Den

Always in search of interesting things to post. Armed with knowledge and dangerous with the ladies.
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22 Responses to Sunday on Earth

  1. jimhitchcock says:

    So what’s for breakfast? ­čÖé

    Like

  2. Den says:

    Sold the Miata yesterday and the expensive repair problems with it, dammit, I liked driving it and the top down experience was amazing. However Mazda made two year emission mistakes on 99 and 2000 years causing much SMOG nonsense.

    I would like to go back in time to a pre-SMOG car, maybe a Corvair?

    Like

  3. David B. Benson says:

    I’ve never seen such an arc. Have seen double rainbows.

    Like

  4. ┬║┬┐carol says:

    I saw one of those here once. I was sitting out in a lawn chair on the side of the house, leaned my head back and looked straight up in the sky. A streak of a rainbow like the one in your picture was up there. It wasn’t a rainbow, no arc with a beginning and an end. Just a streak 4 to 6 inches if I held two fingers up in the air. I didn’t see many clouds in the sky at all, it was pretty clear but I’ll consider it was a circumhorizon arc anyway.

    Like

  5. ┬║┬┐carol says:

    Jill picked Quincy up around 2:30. Decided to dye my hair, so I’m sitting here looking like an ugly bowling ball, hope no one shows up to visit. Good thing there is pretty much a zero chance of that.

    Like

  6. ┬║┬┐carol says:

    Took my blood pressure before I dyed my hair, it was 112/69. Yikes, turned machine off then back on and tested again…103/65. ­čśŽ

    Took it again just now, a reasonable 130/74. Guess I’ll live.

    Like

    • David B. Benson says:

      Much better at the lower figures.

      Like

      • micki says:

        I think Carol’s BP is better at 130/74. The other numbers are too low. Ask any GOOD cardiologist — that overly aggressive lowering of BP causes more problems than it staves off. Falls, confusion, insufficient oxygen rich blood flow to the brain. 103/65 is not your friend! That’s my opinion and I’m sticking to it.

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      • micki says:

        Oh! And one other “risk” factor with aggressive lowering of BP — a biggie!

        Increased risk for acute kidney injury or failure.

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      • David B. Benson says:

        Depends upon how much one has been exercising and so pulse rate. When I exercise my blood pressure goes down as the blood vessels dilate to pump more blood around faster.

        I agree that a resting systolic reading under 110 is kinda low. But contrawise a resting reading of 130 is at the upper limit.

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  7. Den says:

    90 here, hotter down the hill, I’m staying put. Took a rash of pictures for tomorrow.
    I figured I would get the good long distance views before it got smoky from some fire somewhere.

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  8. David B. Benson says:

    Up to 80 ┬░F so the local pizza parlor has the air conditioner on; this causes a draft so I hafta wear my jacket.

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    • Den says:

      Wasting utilities no doubt.
      I would assume a higher usage if the establishment has large doors that open and close frequently, would make cooling usage higher cool in some areas. I would try a different corner, might get lucky. ­čśë

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  9. David B. Benson says:

    Consider what both the Mayo Clinic and Wikipedia write about hypotension: systolic below 90 mmHg or distolic below 60 mmHg and there are symptoms. So 103/65 is fine.

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    • David B. Benson says:

      Ambiguous. (<90 or <60) and symptoms

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    • micki says:

      So 103/65 is fine.

      Often, we are on the same page. On this, we are not. I don’t give a flip what Mayo or Wikipedia says — one size does not fit all. In the “elderly” defined by JAMA (not me) the “elderly” is +65, 103/65 is not acceptable as a target (or sustained) BP reading.

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  10. David B. Benson says:

    To the TVD bridge and return in 45 minutes. It’s not that I walked faster but rather it takes me a minute to go down the stairs to the street and put the walking stick loops on my wrists. Same in reverse at the end.

    A bird of prey, not a Swainsen’s hawk; a skein of Swainsen’s hawks; a wedge of geese.

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