Earliest sunset time on 12/12/12

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Dave Brown
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Earliest sunset time on 12/12/12

Post by Dave Brown » Wed Dec 12, 2012 5:15 pm

Yes odd, but true :wink: Although the longest night is (21/22) 12/2012,the earliest sunset is today on 12th. From today sunset times get later, although the days are still shortening. Sun rise times continue to get later until 1st Jan. :wink:
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Re: Earliest sunset time on 12/12/12

Post by GoggleboxUK » Wed Dec 12, 2012 5:28 pm

icon_cheers The suns has turned the corner!

I do find this odd though, I would have thought it would be the winter solstice.
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Re: Earliest sunset time on 12/12/12

Post by The Codfather » Wed Dec 12, 2012 5:31 pm

I wish it was fitted with a turbo
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Re: Earliest sunset time on 12/12/12

Post by RogerBacardy » Wed Dec 12, 2012 5:44 pm

I believe it's because of the Earth's daily anti-clockwise rotation pushing against its anti-clockwise orbit of the sun, thus skewing the latest sunrise/ earliest sunset away from the actual winter solstice.

You'll notice that they're symmetrically pushed out by approx 10 days from the 21st.


edit - mistyped as I was working at the same time, honest!
Last edited by RogerBacardy on Wed Dec 12, 2012 6:18 pm, edited 1 time in total.


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Re: Earliest sunset time on 12/12/12

Post by Dave Brown » Wed Dec 12, 2012 5:51 pm

RogerBacardy wrote:I believe it's because of the Earth's daily clockwise rotation pushing against its anti-clockwise orbit of the sun, thus skewing the latest sunrise/ earliest sunset away from the actual winter solstice.

You'll notice that they're symmetrically pushed out by approx 10 days from the 21st.
It's clockwise viewed from the south pole, anticlockwise from the north pole. Where do they reference rotation from ?
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Re: Earliest sunset time on 12/12/12

Post by Conifers » Wed Dec 12, 2012 6:15 pm

It's because the Earth's orbit is an ellipse, not a perfect circle. This means the Earth moves faster at some points of its orbit than others; at the moment it is running slightly ahead of its equivalent circular-orbit position, so sunrise and sunset times are pushed slightly backward.


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Re: Earliest sunset time on 12/12/12

Post by Dave Brown » Wed Dec 12, 2012 6:36 pm

Conifers wrote:It's because the Earth's orbit is an ellipse, not a perfect circle. This means the Earth moves faster at some points of its orbit than others; at the moment it is running slightly ahead of its equivalent circular-orbit position, so sunrise and sunset times are pushed slightly backward.
I notice that we are getting closer to the sun looking at the chart so, am assuming that is the faster/flatter part of the orbit.
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Re: Earliest sunset time on 12/12/12

Post by Conifers » Wed Dec 12, 2012 7:00 pm

Dave Brown wrote:
Conifers wrote:It's because the Earth's orbit is an ellipse, not a perfect circle. This means the Earth moves faster at some points of its orbit than others; at the moment it is running slightly ahead of its equivalent circular-orbit position, so sunrise and sunset times are pushed slightly backward.
I notice that we are getting closer to the sun looking at the chart so, am assuming that is the faster/flatter part of the orbit.
Yep, that's right. Perihelion (closest to the sun) is on 4 January.


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Re: Earliest sunset time on 12/12/12

Post by GoggleboxUK » Wed Dec 12, 2012 7:06 pm

So it's what's known as Procession then?
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Re: Earliest sunset time on 12/12/12

Post by Conifers » Wed Dec 12, 2012 7:10 pm

GoggleboxUK wrote:So it's what's known as Procession then?
Nope - that's different, the slow movement of the Earth's polar axis in a circle, takes about 26,000 years. See more here.


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