Geology and Physics Guys

Discussion in 'Off Topic [BG]' started by Lonesomedave, Dec 23, 2013.

  1. How hot is the Earth's core...and does the temperature increase in a linear fashion as you dig your (theoretical....:D) hole through the Earth?

    I know, I could probably look this up on wiki etc, but I am in no hurray...and would like to hear the thoughts of anybody who cares to respond.

  2. Hi.


  3. According to Al Gore, it's millions of degrees. LOL
    . it's actually closer to 10,800 F (6000c)
  4. Don't think it'll be linear, it's heterogenous from the surface crust to the inner core, moving through different phases and materials with different heat transfer coefficients. Plus in the liquid outer core you'll have currents, so that won't be linear.
  5. 1958Bassman


    Oct 20, 2007
    Because his saying it's millions of degrees is plausible and he DID say he invented the internet, did he really?
  6. BassyBill

    BassyBill The smooth moderator... Gold Supporting Member

    Mar 12, 2005
    West Midlands UK
    Dave - why do you ask? Just curious.

    It's interesting to speculate on what would happen to someone who jumped into the hypothetical hole, wearing a special, hypothetical, temperature-resistant, friction-free-surface jumpsuit and any necessary life-support apparatus.

  7. RxFunk


    Dec 2, 2012
    That sounds like the beginning of Star Trek:Into Darkness.
  8. Veritasmench


    Dec 10, 2013
    The inner core could be over 10,000 degrees.

    There are a number of reasons why it gets hot (and hotter) as you start going down into the Earth. The primary reason is radioactive decay.

    (I do not work as one anymore but I am a Physicist.)
  9. because we've already started our dig, and i just want to be prepared....:D

    Nah, just got curious and i miss our physics discussions from last guys straightened me out on the faster-than-light thing, so, naturally, i came here first with ANY such question

  10. fishtx


    Mar 30, 2007
    Dallas, TX
    Endorsing Artist: Spector Basses/Genz Benz - RIP/Mojo Hand FX
    yep...about 10,000F give or take...supposedly about the same as the surface of the Sun...
  11. NWB


    Apr 30, 2008
    Kirkland, WA
    Oh snot, I'm a geologist and I can't remember what the temperatures of the mantle, outer core, and inner core are.

    There are hotter spots within the mantle that result in magma migrating to the surface in such places as Hawaii, Iceland, and Yellowstone. I find it interesting that these hot spots are stable over some fairly long periods of time as the crust slides around over them.
  12. BassyBill

    BassyBill The smooth moderator... Gold Supporting Member

    Mar 12, 2005
    West Midlands UK
    It does a bit. But if the hole went straight through the planet, you'd have some interesting consequences.

    Suppose you dug from the north pole straight through to the south pole and then stepped in (you might want to do this with a friend waiting for you at the edge of the hole). Travelling staight and with nothing to bump into, you'd accelerate towards the centre of the Earth, and with your friction-free magic suit that negated air resistance, you wouldn't reach terminal velocity. You'd get faster and faster until you reached the earth's centre travelling at about 24,000 miles per hour. Then you'd start to slow down until you reached zero velocity at the point where your centre of mass was exactly the same distance outside the south pole exit as it was outside the north pole entrance when you stepped in. The only difference would be that your head would be right next to the hole with your feet sticking up in the air. Then you'd immediately fall back in the opposite direction, head first, go through the centre at 24,000 mph again and eventually reach a stop in your exact stepping off position at the North pole, where that friend would now come in very handy by grabbing hold of you to stop you repeating the two way trip for all eternity. The round trip from north pole to south pole and back again would take just under 1 hour and 14 minutes. :D
  13. stevetx19


    Sep 28, 2006
    Denton, Texas
    that sounds fun
  14. BassyBill

    BassyBill The smooth moderator... Gold Supporting Member

    Mar 12, 2005
    West Midlands UK
    It sure does sound fun! If anyone wants to check the figures, I used six million meters as the radius of the spherical earth and a constant value of 9.81 N/kg for g. In practice this value would increase VERY significantly as you fell and this would increase the speed of the trip and shorten the time taken. It would also stretch and squeeze you into oblivion. ;)
  15. Tituscrow

    Tituscrow Banned

    Feb 14, 2011
    NW England
    Miles per hour? MILES PER HOUR?

    Mixing units sir...tut tut :)

    Might be worth adding that this thought experiment is a great way to introduce Simple Harmonic Motion.
  16. NWB


    Apr 30, 2008
    Kirkland, WA
    Perhaps even more important is that you wouldn't be able to take notes, photos, sketches, etc. of your observations along the way.

    What's the use in going through the Earth if can't document your findings?

  17. BassyBill

    BassyBill The smooth moderator... Gold Supporting Member

    Mar 12, 2005
    West Midlands UK
    Hey, for an old petrol head like me, mph is the way to go. I got the velocity in m/s first, obviously, but converted it into something that could actually be understood, particularly by Americans. :p

    When I'm driving around I know how many mph I'm doing and have no idea at all about the m/s thing. In class, of course, it would be SI all the way. ;)
  18. it's made of mashed potatoes. warm and buttery.
  19. Wouldn't g decrease towards 0 as you approached the center of the earth's mass? This seems to make sense in terms of the Newtonian equation as two terms (r and m(earth)) tend to 0 as you go towards the centre of it from the surface. I.e. as you get closer to the centre you can only use the mass between your point of reference and the centre of the earth, not the entire mass of the earth. At any rate as r->0, g will-> 0 regardless of what mass number you use. I think. Am I misunderstanding this?