Happy Equinox, Everybody.

[Lionel Mandrake]

Today there are 12 hours of daylight and 12 hours of darkness. The sun rose due East and will set due West. These things are true everywhere on the globe except near the poles, where the sun is skimming along the horizon.

The sun is setting at the north pole and rising at the south pole, but doing so very slowly.

For the next six months there will be constant daylight at the south pole, but no daylight at the north pole.

[kayakjohnny]

1. Thanks for the reminder and Happy Equinox to you as well.

I'm so glad you posted this.

Cheers.

[Lionel Mandrake]

3. You're welcome.

I'm glad you liked it. :)

[rug]

2. The penguins are happy.

[Lionel Mandrake]

4. But not the polar bears.

[MerryBlooms]

5. Thanks and same to you. :) n/t

[Lionel Mandrake]

11. You're welcome.

:)

[MiddleFingerMom]

6. Bill Withers at the North Pole:

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.
.
http://www.youtube.com/watch?v=tIdIqbv7SPo&feature=related
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.
.

[Lionel Mandrake]

8. Heh heh.

Maybe he was at the south pole a few months ago.

[Highway61]

7. Wow..pretty cool

didn't know that. Thanks.

[Lionel Mandrake]

9. You're welcome.

I tend to get didactic now and then. Please kick me if I overdo it. ;-)

[CaliforniaPeggy]

10. My dear Lionel Mandrake!

I knew today was the equinox, but I hadn't really thought what that meant in terms of what's happening along the poles.

Thank you for that very cool bit of information!

:hi:

[Lionel Mandrake]

12. My dear CP,

You're welcome. I'm glad you liked it. :)

It's always cool at the poles, but it gets really cold there in the winter.

[pokerfan]

13. Anna's Lemma

(We are currently where the curve crosses the equator on the right side -sun fast - and heading south. There doesn't seem to be anything we can do about it as I remember this same thing happened last year and the year before that...) :(

[Lionel Mandrake]

18. It's Anne X. Horrible

Resistance is futile. ;-)

[rurallib]

14. oddly according to the sunrise/sunset chart I look at every day

(it is some kind of genetic defect I have I think) the 12 hour day/night doesn't happen until Monday. Has me in a dither.
http://aa.usno.navy.mil/cgi-bin/aa_rstablew.pl

[petronius]

15. Your chart is correct - the equinox refers to the center of the solar disk

Since the top edge of the sun rises before the center, and sets after the center, there is more than 12 hours of daylight on the equinox itself...

[Lionel Mandrake]

16. Your genes are just fine.

In reality there is a gradual transition from night to day, or vice versa, so that you can't really say that daylight begins or ends at a particular instant.

What I wrote assumes a strictly geometric model, neglecting atmospheric effects and the finite diameter of the sun.

Atmospheric refraction tends to accelerate sunrise and delay sunset, and that may explain why it takes a few extra days for your chart to show exactly 12 hours of daylight.

Clouds have just the opposite effect, making the sky darker than it would otherwise be at or near sunrise or sunset.

BTW, your link seems to be broken.

[rurallib]

17. I am not surprised the link didn't work

it is the naval observatory site and I don't think you can link to the chart which is what I tried to do.

[MrMickeysMom]

19. I always feel just a little bit sad at the fall equinox...

I so love the change of seasons, though, especially since returning from the South to the North.

[Lionel Mandrake]

21. Yes, there's something sad about Autumn

For me, it is the memory of having to go back to school, which I hated as a child.

Now that I am well into geezerhood, I look forward to school.

We don't have seasons at the beach in southern California. We have no Fall colors.

But we don't have to shovel snow, either. :)

[MrMickeysMom]

23. You got me on that one - D-Oh/snow...

But, if I wasn't made to see the change in colors, thus softening me up for the next thing, it would really be an ass-kicker when the snow flies.

[Lionel Mandrake]

24. That's gorgeous!

That pic almost makes me wish I lived where there are seasons.

Almost.

[UTUSN]

20. Well, THANK you for noticing the change in how the SUN

[UTUSN]

22. & here is an illustration from Mr William BLAKE. Will look for musical accompaniment

[Lionel Mandrake]

25. Here you go.

http://www.youtube.com/watch?v=a8o4os6Um6g