Earth's Internal Heat

• Crust the uppermost and thinnest layer of Earth

• The crust is the uppermost and thinnest layer of Earth. It can be classified into

  continental and oceanic crust.
• is the layer below the crust. Its uppermost part, together with the crust, makes up the lithosphere. The lower mantle is called the mesosphere.


  mantle
• Mantle convection is necessary to transfer heat and drive processes on the surface of the planet.
• It is a result of different temperature and pressure conditions in the plastic mantle, which can flow, and leads to hotspot activity at the surface. 



  Mantle convection
• The innermost layer is the core, both composed of iron with subordinate nickel.
• It can be divided into the liquid outer core and the solid inner core.
• Rocks are classified into three

  igneous

  sedimentary

  metamorphic
• categorized based on minerals present, texture, and formational process.
• Geothermal gradient is the increase in temperature with respect to the increase in depth.
• Earth's internal heat is produced by extraterrestrial impacts, gravitational contraction of Earth's interior, and radioactivity of isotopes.
• What is Earth's internal heat is produced by?

  extraterrestrial impacts, gravitational contraction of Earth, radioactivity of isotopes.
• Convection in the Earth's interior is the motion of hot fluid from one place to another.
• Earth's thermal budget is the measure of the amount of heat produced in the interior and released at the surface.
• It is believed that Earth has been releasing primordial heat (heat from its early formation) and heat generated in the Earth's interior through radioactive decay.
• The heat flow from Earth's interior powers the convection within the mantle and the core and contributes little to the heat balance or convection in the atmosphere and oceans.
• The thermal budget is computed through the study of energy emitted by the four major isotopes that produce heat namely uranium-238, uranium-235, thorium-232, and potassium-40.
• Seismic wave reports show that the outer core is a fluid layer. Therefore, convection currents can occur within the outer core which enables heat movement upward. 
• According to the nebular theory, heat energy was produced when great amount of kinetic energy produced by moving objects was converted to heat energy.
• What led to an increase in the gravitational attraction causing the contraction of Earth into a smaller volume?

  Accretion of particles
• What is produced to the process radioactive decay as by product?

  heat
• What does some scientists believe about the Earth's thermal budget?

  Completely balanced and same amount of heat is released and produced in the planet.
• This idea is based on the notion that if more heat is generated than released, the mantle would heat up and discharge large amounts of heat in order to reach thermal equilibrium.
• The crust is the uppermost and thinnest layer of Earth. It can be classified into

  continental and oceanic crust