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Green Planet (My project for energy)

  1. Oct 21, 2008 #1
    Hi Everyone,

    My teacher gave me a project to created anything that need not to be build out physically.

    I gave the tittle green planet.

    So the idea is that one could create a VACUUM tunnel from the north to south pole (or any 2 points that is a diameter of the earth) and a "vehicle" where human is put into and use gravitational pull to accelerate to the centre of the core and then deccelerate to reach the other hemisphere(north to south; east to west & vice versa).

    I have problems that need to be answered:(please help to answer the qs that u know; thanks)
    Qs 1) When you go underdiving, I heard that if you go deeper and deeper, your ears starts getting more and more painful. (so is it because of air pressure? If yes, so does air pressure changes occur as you go deeper(higher gravitation) or higher(lower gravitation) because of gravitation? In other words air pressure changes because of gravitational pull?)
    Qs 2) What is air pressure definition? (is it the air molecules are getting more compress/closer?)
    Qs 3) So does qs 1 and 2 apply to my above qs(If it does have pressure, will it cause pain to yr ear) , don't forget my tunnel is vacuum and not liquid and the vehicle will be filled with oxygen adjusted to atmospheric pressure.(So when I get deeper to the core of the earth, will my pressure in the vehicle increase?
    Qs 4) If this idea simply make no sense, please tell me as I need to present this and I do not want to embarrass myself by all the wrong facts so please feel free to tell me.

    For the material, I have come up with a carbon material to withstand the heat of the core. So if there is any problem regarding my project, feel free to correct me as I lack the knowledge now but I love Physics and plan to major in physics once I leave school.
    Qs 5)So if any physics and/or biological theory denied human survival in this kind of "vacuum travelling" please correct me. (I will change from human to shipping gds by "vacuum travelling" and if this also does not work please correct me also.)

    Thanks a lot
    Last edited: Oct 21, 2008
  2. jcsd
  3. Oct 21, 2008 #2


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    Air pressure is the weight of all the air above you. Air isn't very heavy - a cubic metre of air only weighs around 1.2Kg but there is a column of 8,000m of air above you so the weight on each square meter is about 10tonnes. As you go further down each 8km will add another 10tonnes of pressure on each square m, just as when you go up a mountian there is less air above you and so less weight and your ears pop in the other direction.

    When you go scuba diving the effect is more worse because each cubic metre of water weighs 1 tonne.

    Rememebr that your tunnel doesn't have to be from the north to south pole (there isn,t much demand for traffic between polar bears and penguins) down is the same direction from anywhere - get a globe and see which cities are nearly opposite each other.
  4. Oct 21, 2008 #3
    Yup thanks, anyway I mean any 2 points by diameter eg new york to perth (australia).
    Anyway I am puzzle as in if it is vacuum, there shouldn't be any pressure as there is no air molecules.
  5. Oct 21, 2008 #4


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    Yes you would have to have the tube in vacuum anyway to stop the air resistance slowing you down (and melting your vehicle).
    An interesting result is that if you get the curve right is it possible to link any two points on the surface with a tunnel where if you dropped something in one end it would reach the other (in theory assuming no friction) - it doesn't have to go therough the centre.
  6. Oct 21, 2008 #5
    I have just updated my qs.

    Btw I am very curious as in if you pressurise an underwater machine(with ppl in it) why the pressure will change when you go deeper? is it because of the water but aren't you seperated from the water or is it gravity or other thing that affect air pressure as you go deeper underwater.

    Another qs, lets say you take out all the ocean water and you are at the same depth as above maybe 4000m below sea level and in the underwater machine(but now there is no water and just ocean floor w/ dead coral reef), will the air pressure be reduce, same, increase when compare to the above examples.
  7. Oct 21, 2008 #6
    But why there is friction, there isn't any air molecules to cause terminal velocity so I guess it will accelerate until it starts to go up the surface again. I got another qs, if you make a curve tunnel, will it collide with the wall because it is moving so fast relative to the earth if you accelerate long enough(a few minutes) so the damage if it hit the tunnel wall will be devastating. Do you think that the use of repelling will solve the issue (both the curve part of the tunnel and vehicle be magnetise by the same(north) pole. And will it slow down?

    Anyway thanks for solving the previous qs, I appreciate that.
  8. Oct 21, 2008 #7


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    You could put it on rails or do a mag-lev type design to keep it from grinding against the walls of the tunnel.
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