Caption: This computer-generated image shows the different layers of the Earth: The outer solid crust, the viscous upper and lower mantle, the liquid outer core, and the solid inner core.
Posted on 11/10/2011 5:47:19 AM PST by decimon
Caption: This computer-generated image shows the different layers of the Earth: The outer solid crust, the viscous upper and lower mantle, the liquid outer core, and the solid inner core.
Credit: ESRF
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ESRF inaugurates unique new X-ray facility
Grenoble -- Scientists will soon be exploring matter at temperatures and pressures so extreme it can only be produced for microseconds using powerful pulsed lasers. Matter in such states is present in the Earth's liquid iron core, 2500 kilometres beneath the surface, and also in elusive "warm dense matter" inside large planets like Jupiter. A new X-ray beamline ID24 at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France, allows a new quality of exploration of the last white spot on our globe: the centre of the Earth.
We know surprisingly little about the interior of the Earth. The pressure at the centre can be calculated accurately from the propagation of Earthquake waves, and it is about three and a half million times atmospheric pressure. The temperature at the centre of the Earth, however, is unknown, but it is thought to be roughly as hot as the surface of the sun.
ID24, which was inaugurated today, opens new fields of science, being able to observe like in a time-lapse film sequence many rapid processes, whether laser-heating of iron to 10.000 degrees, charge reactions in new batteries or catalysts cleaning pollutants. It is the first of eight new beamlines built within the ESRF Upgrade Programme, a 180 million Euros investment over eight years to maintain the world-leading role of the ESRF. ID24 extends the existing capabilities at the ESRF in X-ray absorption spectroscopy to sample volumes twenty times smaller and time resolutions one thousand times better than in the past.
(Excerpt) Read more at eurekalert.org ...
I doubt that gravitation there is null. It´s evidently the rotation of the inner core that gives rise to the magnetic field. Plus, even though it it is solid, if they´re right about the temperatures and pressures throughout, it must still be a very dynamic environment. Thus there would be no ¨center¨ in the way we usually conceive of it, but a constantly churning mass across it, from the classical to the quantum levels. And, it´s also subject to tidal forces of the Sun and Moon which constantly knead the entire Earth, and would also act to keep the ¨center¨ in a constant state of flux.
What it is isn’t evolution or geological conunlittledrummer boys. It is constant creation. And you are playing your part in that. You signed the paperwork. Just like everybody else.
I believe it was Darwin who was trying to figure out the age of the earth, but because he and other scientists of his time knew nothing of radiation, only though it was a few hundered thousands of years. Yet as the layers of sediments were examined, it seemed that this time period was too short to explain the remains.
In Darwin’s time uniformitarianism was the accepted concept. However, with the discoveries of the Alvarez folks, and the understanding of the great extinctions such as the Permian, and Cretaceous among others I think most scientists accept that enviroments may be uniformitarian but interrupted by major and minor catastrophes as well. The major die offs caused and the new environments formed allow for the rapid evolutionary diversification of the remaining life forms. For example, at the Permian end the protomammalian therapsids seemed more successful than the protodinosaurs. However, after the great dying, the dinosaurs flourished for 150 million years while the mammals evolved as small timid fringe animals. Then with the death of the dinosaurs, the mammals rapidly evolved to fill the many vacant niches left by the dinosaurs.
Darwin was particularly impressed by the development of the various finches on the Galopagus (sp?) Islands. He concluded that probably one kind of finch was blown far out to an island there, and then evolved to have large thick beaks to eat hard seeds. Others thin beaks for other purposes, etc. These observations were a major factor in his development of the idea of evolution.
A very interesting recent book is “Endless Forms Most Beautiful” by Sean Carroll, about the latest discoveries in evolutionary developmental biology. This book points out that as evolution progresses, ancient genes and structures are reused. For example, segmented earthworms, segmented crustaceans and insects to the spinal column of higher forms all develop from the same roots. Regarding the chromosomes, currently the male Y chromosome is gradually diminishing and may some day disappear. Perhaps a pair was lost during the evolution from ape precurser to hominid precurser.
Pardon my ignorance but do not all sexually reproducing animals have a Y chromosome? Do you have some reference for the assertion that the human male Y chromosome is "gradually diminishing"?
Perhaps a pair was lost during the evolution from ape precurser to hominid precurser.
Yeah. "Perhaps." Or maybe the whole evolution thing is a crock.
ML/NJ
This may sound like a dumb question to any geophysicists out there, but if the temperature at the center of the Earth is so darned hot, why isn’t it the same for Mars - or the moon?Not dumb. No question is. But first on the Earth.
'We' have a molten heavy metal core, it gives off heat and our magnetic North and South poles, so Iron must be 'down there', along with Uranium. But without that molten Iron we'd be screwed as the Sun's and other Space Rays like X and Gamma would fry us (Gamma Rays are the Big Killer Gun in the Universe). The Aurora Borealis are atomic particles ('the Solar wind') being drawn to our magnetic poles. Magnetic North is never at our 'North Pole' and varies from location to location. It's called 'Declination' and where I'm at it's -3.2o (very important to know 'in the field').
Now to the Moon and Mars, I'll take Moon first:
Moon: The moon was created when Earth V1.0 was hit by another proto-planet (can't recall its name now, so call it 'X') in our young solar system days. A part of planet X combined with Earth V1.0 (thank you Gravity) to make it today's size, Earth V2.0, but a huge chunk was thrown into space. Gravity took over and gave us the 'moon'. So it's solid rock, no molten core like Earth. And therefore no heat. That's why the Apollo Missions were somewhat of a bust. It's the same 'rock' Earth is made of, and same age. NASA was hoping for something else.Hope this helps.Oh and originally the moon's orbit was much, much closer to the Earth than today. And it's orbit keeps growing, 38 mm per year (sorry for the Canadian measurement), so one future day it will be 'gone', and that will have dire effects on the Earth - but we'll (Humans) be long dead.
Mars: Mars once had a liquid (molten) core like the Earth and with that, heat and an atmosphere, and also flowing water. But the core solidified, and Mars lost 'everything'. Also, without a molten core Mars has no real 'North' or 'South' so a regular 'army' magnetic compass wouldn't work there. 'The WHY' Mars' core solidified is still being studied (to my best knowledge). And without a magnetosphere Mars is always bombarded with those nasty killer Rays (atomic particles).
Thank you for a most informative and excellent response.
About a year ago I attended a fascinating lecture at the Carnegie Institution in DC. The presenter spoke of the shrinking X chromosome, and then described a fascinating level of complexity with another species that, if I remember correctly, had several X, one X or no X but behaved as a male. It was very puzzling. I think it might have been naked mole rats, but I have to go to work soon, so maybe you would want to Google that.
My bad, in the previous Comment I said X when I meant to say Y. Old age. ;-(
Another problem for Mars and us is that being somewhat smaller, the escape velocity from Mars is lower. Thus it has lost a lot of its atmosphere over time, and who knows what greenhouse warming potential. It will thus be very hard to live there if we do go. Recently read Ben Bova’s book on Mars. Anyone know how accurate it was in its descriptions?
At the EXACT singularity center of the planet the gravity would be zero as all of the mass is 'above' you. The pressure would be still be immense. Equal and opposite pressures do not balance out; they double up.
Radioactive decay and fluid dynamics produces friction and heat inside the core of the Earth. The moon and Mars have both ‘cooled off’ and have solid cores.
He was in the pool!
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