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ordbrae | 18:18 Sat 13th Jul 2013 | Science
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Around the 4th of July each year the Earth is furthest from the Sun despite the hottest period in the UK
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Hi cweus,

I only clicked one link - the books.google one and was totally drawn in. Scrolled back several pages and read the whole article, from the start, in the end.

Fascinating to read their attempts to explain extreme changes in past climate, as written in Britain's rocks, without the benefit of modern theories, like continental drift and so forth.

Even so, the discussion around orbital eccentricity addressed a nagging question I had in mind which is always glossed over every time they run those animations of ice-age ice sheets advancing and retreating, which was "do ige ages affect both hemispheres at the same time?"

If I understood correctly, eccentricity changes cause one hemisphere to experience greater seasonal extremes - hotter summers and colder winters - while the other hemisphere loses all contrasts and has a perpetual spring.

What wasn't stated was whether the eccentricity cycle continues and these situations for either hemisphere become reversed in a neat way or whether this business of the precession of the equinoxes complicates the pattern. Reference is made to 'lesser minima and maxima' within the eccentricity cycle itself but that's not the same thing as what I mean.

If the precession of earth's path around the sun took the same length of time as the eccentricity change then it would always be the same hemisphere being hit by the extremes. If the rates were different then there would be a complex pattern - like when different fequencies of sine wave are added together.

Indeed the Milankovitch cycles take into acount additional factors like changes to axial tilt angle and precession of earth's axis. I seem to recall it's at least four, possibly five, cyclical factors, all added together, with great complexity, as a result. Where we are on the cycle in the present day, I have no idea - it never comes up in debate.
Ordbrae- I too was intrigued by that pendulum forty plus years ago and have always had a hankering to go back to the Scottish Science Museum but could never remember where exactly in Edinburgh it is....!
Matheous-2
Ordbrae- I too was intrigued by that pendulum forty plus years ago and have always had a hankering to go back to the Scottish Science Museum but could never remember where exactly in Edinburgh it is....!
16:37 Sat 27th Jul 2013

https://maps.google.com/maps?q=Scottish%20Science%20Museum&rlz=1C1CHMI_enUS330US331&;um=1&ie=UTF-8&hl=en&sa=N&tab=wl

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