jump to last post 1-2 of 2 discussions (4 posts)

Question About The Earth's Core and Marianus Trench

  1. Lady Guinevere profile image61
    Lady Guinevereposted 4 years ago

    Question About The Earth's Core and Marianus Trench

    If the earth's core is so hot and the magma is so hot in the volcanoes close to the surface then why isn't the Marianus Trench warm or hot at the bottom?

  2. SidKemp profile image95
    SidKempposted 4 years ago

    Let's separate this into pieces. The Earth's core is small and at the center of the earth, over 2,000 miles down. The Marianas Trench, where the Earth's crust is thinnest, allows the Earth's mantle (not core) to be very close to the seabed.

    And the Marianas trench is warm. The temperature increases as you get deeper. At the bottom of the trench, there is a very thin layer of hot rock. I think it is about 300 degrees, but I may be out of date about that (not that it's changed, but there is newer research.) The rock not far beneath that is magma - molten rock of the Earth's mantle, and it is a couple of thousand degrees.

    Water is a very good conductor and convector of heat. The water of the vast ocean of the Marianas trench is constantly receiving heat from the Earth's mantle and rising. It is so hot that, if it were at sea level and not under pressure, it would boil. But it rises, and is quickly replaced by cool water, which is heavier and flows in.

    So the Marianas Trench acts like a radiator, constantly cycling in cool water to cool the hot rock just beneath the trench.

    1. Lady Guinevere profile image61
      Lady Guinevereposted 4 years agoin reply to this

      Thank you very much for that information.  The question arose in my mind after I watched the New Evidence of Mermaids and such.  They said that the water was colder and darker but being so close to the center I thought it would be warmer instead.

    2. SidKemp profile image95
      SidKempposted 4 years agoin reply to this

      The water is darker and under greater pressure. And, in the general depths, being further from the sun, also colder. But right near the earth warmed by magma, and at undersea vents, it is hotter.

 
working