It plays up the human angle bringing a bit of intimacy to a place long forgotten.
http://ngm.nationalgeographic.com/2008/ ... /gwin-text
Green Sahara Article from NG
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Sam Salmon
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Green Sahara Article from NG
One of the best articles I've read from NG for a long time (and a long read on a computer screen.)
It plays up the human angle bringing a bit of intimacy to a place long forgotten.
http://ngm.nationalgeographic.com/2008/ ... /gwin-text
It plays up the human angle bringing a bit of intimacy to a place long forgotten.
http://ngm.nationalgeographic.com/2008/ ... /gwin-text
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Rokcet Scientist
I enjoyed it too. A very good read on a subject that's always fascinated me.
I'd still like to know some more about this axis wobble, though. Why did it happen then? And could it happen again?
.
I'd still like to know some more about this axis wobble, though. Why did it happen then? And could it happen again?
.
Ishtar of Ishtar's Gate and the Hanging Gardens of Babylon.
Could it happen again? Yes Ish, depends on the cause but one date is significant, 12000 years, in other words the time of the major melting of the ice sheets in the northern hemisphere.
If you spin some thing then add weight to one hemisphere the spinning mass will attempt to attain a fresh equilibrium, same applies when you remove it.
Roy.
If you spin some thing then add weight to one hemisphere the spinning mass will attempt to attain a fresh equilibrium, same applies when you remove it.
Roy.
So ... what about the melting of the polar ice caps now? Could the meltwaters cause a similar weight to throw things off balance again?
Ishtar of Ishtar's Gate and the Hanging Gardens of Babylon.
It happens all the time Ish, but to answer your question more accurately, not to the degree of 12000 years ago.
I think it is well known that the circumference of the Earth is less across the poles than at the Equator, technically it's called an oblate spheroid, what is less commonly known is that if you were to measure the radius from the centre to the sea level in the Atlantic at London's Lat it would be greater than on the same Lat below the Equator.
Centrifugal force tries to flatten the Earth into a disc, gravity wants to create a sphere. As there is more land above the Equator than below the planet is shaped like a top.
Now add an increase in mass and height above sea level to the northern hemisphere over a longish period and the Earth will accommodate it by spinning in its most balance form.
It is doubtful that the ice melted evenly, so the likely result would be a series of wobbles, some of which may well have been quite violent.
Your interest in folk law etc Ish may well show some evidence of this as I recall reading that within some early civilisations there are records of a period when the year varied in length. I believe the Chinese recorded such a time.
Roy.
I think it is well known that the circumference of the Earth is less across the poles than at the Equator, technically it's called an oblate spheroid, what is less commonly known is that if you were to measure the radius from the centre to the sea level in the Atlantic at London's Lat it would be greater than on the same Lat below the Equator.
Centrifugal force tries to flatten the Earth into a disc, gravity wants to create a sphere. As there is more land above the Equator than below the planet is shaped like a top.
Now add an increase in mass and height above sea level to the northern hemisphere over a longish period and the Earth will accommodate it by spinning in its most balance form.
It is doubtful that the ice melted evenly, so the likely result would be a series of wobbles, some of which may well have been quite violent.
Your interest in folk law etc Ish may well show some evidence of this as I recall reading that within some early civilisations there are records of a period when the year varied in length. I believe the Chinese recorded such a time.
Roy.