reply to post by Byrd
Byrd;
You might want to recheck your figures. "Iceball Earth" existed only briefly (relatively speaking) and the ice ages were shorter than the warm
periods. The Cretaceous (warmer than present Earth) lasted almost 200 million years.
Yes in the last 500-700 million years the earth has been warm, but that is only an 1/8th of the erths history.
I was referencing a graph of average world wide temp since the earth formed. It was in an article I read in the journal "nature" about 7-8 years
ago.
I always thought that the earth was usually warm but, the data these researchers had gathered clearly showed the the earths average temp well below
the the freezing point of water.
To counter those 200 million years of temperate to tropical conditions in the cretateous are offset by a billion and half or more years frozen, in
very early days.
earth has only been warm enough to support advanced life on land for 10% of its total history.
Well make that 18% ish, if you take the figure of 500 million years ago for life to take hold on land.
The first billion year years of life could very well have plugged along under a cap of ice.
Our planet is on the edge when it comes to what we call a habitable zone.
Just the slight shift in position relative to the sun, between winter and summer, causes where I live to go from an a daily summer high of 100
degrees, to a daily high in the winter of 40.
And yes you are correct on the Milankovich cycle, and my time scale for it was off, there must be some other cycle that is in the 20ish million
years, cause it is stuck in my head.
As far as the gas and dust I was referencing a very doom and gloom article in Sci Am from a few years ago.
There are regions of gas and dust, that is undeniable. There earth orbits around the galaxy, so it stands to reason that at some point our solar
system will pass through one.
This astronomer was saying that the earths has been travelling through a clear area for quite some time tens of millions of years.
He postulates that were are about to pass into a "dark region".
According to him there is a dark region in the direction of the earths travel.
They cant tell how far away it is or how soon we will reach it, but it is there.
He called it one of the biggest things nodoby is interested in.
Your dinos, coool
Maybe not festering at the poles, but the earth certainly was a festering swamp at the tropics.
And yes, biological speeking festering is best, frozen is dead.
In yet another article about past climate variations the author
And yes there are so many things tht affect the earths rotation and how its crust moves around.
Gravitational tidal forces, heat from the core and so on.
