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Thread: Is the Planet Earth shrinking?

  1. #1 Is the Planet Earth shrinking? 
    The Enchanter westwind's Avatar
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    Or am I being fooled by extra ground shrinkage around where I live? Is it possible that there is a surface contraction occurring? Do we know quite accurately the circumference of the Planet Earth at both Datums? Now, should this be the case for whatever reason, if we have suddenly become smaller, therefore denser, would gravity have more measurable effect? The apple falling faster from the tree? westwind.


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  3. #2  
    Universal Mind John Galt's Avatar
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    The planet is not shrinking in any significant way. Satellite observations reveal some areas rising and some falling. These are precise to within a few centimetres. There would need to be a change of the order of tens of kilometres to have a perceptible effect on gravitational acceleration.


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  4. #3  
    Geo
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    Yeah probably.

    If you were standing on top of a mountain would gravity be greater than in the valley below?

    In NewZealand, our Alps are rising at 10mm per year or thereabouts and slipping at 38mm per year.

    Have you never looked at a map of the Earth's continents in say, the Triassic?
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    Comet Dust Collector Moderator
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  6. #5  
    The Enchanter westwind's Avatar
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    Thanks MW. Have added Australian Popular science to my favourites bar. westwind.
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  7. #6  
    Brassica oleracea Strange's Avatar
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    Quote Originally Posted by Geo View Post
    If you were standing on top of a mountain would gravity be greater than in the valley below?
    It is less because you are further from the center of the Earth.
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
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  8. #7  
    SEEKER Genesis's Avatar
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    2900-7300 kilograms per year hit Earth. However, this does not include the small dust particles. Scientists also estimate between 36 and 166 meteorites larger than 10 grams fall to Earth per million square kilometers per year. Over the whole surface area of Earth, that translates to 18,000 to 84,000 meteorites bigger than 10 grams per year. But most meteorites are too small to actually fall all the way to the surface. Estimates for the total mass of material that falls on Earth each year range from 37,000-78,000 tons. Most of this mass would come from dust-sized particles. (This study was led by P. A. Bland and was published in Monthly Notices of the Royal Astronomical Society.)
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  9. #8  
    Comet Dust Collector Moderator
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    Thanx for posting the source of the numbers you quoted!!
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  10. #9  
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    If it is cooling down, it might be shrinking
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  11. #10  
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    Quote Originally Posted by risto View Post
    If it is cooling down, it might be shrinking
    But since the evidence is that the planet is getting warmer...
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  12. #11  
    The Enchanter westwind's Avatar
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    For Sealeaf. Is it that the Planet is getting warmer.? Where would we begin to take samples to run a trial on this? Through the Earths mantel? No, I believe Warming as such is only Atmospheric Warming. Perhaps enough to eventually melt all the Artic ice cap. The Heat from the Earths inner core is dissapitated through the mantel, noticable at night time, overnight temperatures are rising, here in Australia anyway. ( weather reports ), . So we are losing core heat at night time, some through the day as well, although this is being balanced out by existing Atmospheric temperatures. We are overall cooling down beneath our feet, with our head in a warming Atmosphere. Wot say you Sealeaf? westwind.
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  13. #12  
    Forum Radioactive Isotope Paleoichneum's Avatar
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    If I understand correctly risto and Sealeaf are both talking about the climate. At which point there is ample evidence.
    If more of us valued food and cheer and song above hoarded gold, it would be a merrier world. -Thorin Oakenshield

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  14. #13  
    The Enchanter westwind's Avatar
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    The molten core of the Planet Earth would be generating outwards pressure against the Earths Mantel. We take this as given. OK. So what happens if there is a cooling down of this molten core? A gradual decrease in outwards and upwards pressure? And what would be the consequences of reduced bladder pressure on the Mantel? This is a straight out Physics and perhaps mathematical calculation, certainly something that could be experimentally ascertained. One naturally considers a Mantel callapse. With the heat gone from the core would that mean colder night time temperatures? Appreciate some studied answers to this Hypothesis as I have no understanding of the rate that an inner core of a Planet might cool down. What are the mechanics in play here.? westwind.
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  15. #14  
    Forum Radioactive Isotope Paleoichneum's Avatar
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    There would most likey be some expansion if the pressure was reduced. This would be due to many minerals undergoing phase-shifts from high pressure/temperature forms to colder temperature/lower pressure forms which have a larger crystals structure.
    If more of us valued food and cheer and song above hoarded gold, it would be a merrier world. -Thorin Oakenshield

    The needs of the many outweigh the need of the few - Spock of Vulcan & Sentinel Prime of Cybertron ---proof that "the needs" are in the eye of the beholder.
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  16. #15  
    The Enchanter westwind's Avatar
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    Dear Paleoichneum, Do crystals always behave this way? If so then there must be a lot of applications where this mass growth could usefully be applied, given the required environment. I know of no such situation. If you expand an existing surface, outward growth, that's stretching it a bit isn't it? Of course this is hypothetical. Question; Do molten Inner Cores ever cool down? Have we an example, say Mars? The cooling rate, can an equation be applied that demonstrates one of the Mathematical Laws of the Universe? I would have thought that the cooling rate would be an ongoing process and more rapid then we are experiencing. Does the Earths Mantel provide that much insulation that slows cooling? I would not have thought so. It's a puzzle to me that Planet Earth hasn't cooled off long before this. westwind.
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  17. #16  
    Forum Radioactive Isotope Paleoichneum's Avatar
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    Yes crystals do behave this way, but application of the property is limited do the extreme temperature and pressure needed to force a mineral from its preferred crystal structure to a more compact structure.

    One of the major sources of heat in the mantle at this point is generally accepted to be radioactive decay of heavy elements such as thorium, Uranium, Ytterbium etc...
    If more of us valued food and cheer and song above hoarded gold, it would be a merrier world. -Thorin Oakenshield

    The needs of the many outweigh the need of the few - Spock of Vulcan & Sentinel Prime of Cybertron ---proof that "the needs" are in the eye of the beholder.
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  18. #17  
    Reptile Dysfunction drowsy turtle's Avatar
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    Quote Originally Posted by Strange View Post
    Quote Originally Posted by Geo View Post
    If you were standing on top of a mountain would gravity be greater than in the valley below?
    It is less because you are further from the center of the Earth.
    It's actually not that simple. The corrections made in gravity data for elevated topography around the datum point are positive - that is to say, the surrounding topography gives rise to a lower value than for a perfectly flat topography (because there is a small component of gravitational attraction in an upwards direction).

    The correct answer is that it depends on the height, density and topographical gradient of the mountains.
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  19. #18  
    Professor of Articulation Zesterer's Avatar
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    No planet earth is not shrinking, because parts of 'it' are also expanding. This counter-balances the effect of certain sinking regions. Its all part of the natural processes the earth goes through.
    Science cannot solve the ultimate mystery of nature. And that is because, in the last analysis, we ourselves are a part of the mystery that we are trying to solve.
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