5.2 How to Cool a Planet
5.2.1 Types of Heat Transfer
Heat always wants to move from areas of higher temperature to areas of lower temperature. This means any heat held inside a planet wants to eventually move to the surface and escape out into space where it is much colder. Read the Transfer of Heat Energy webpage on the National Oceanic and Atmospheric Administration’s website to refresh your understanding of the three methods of heat transfer.
Ask Yourself
Try to answer the following questions:
- Which type of heat transfer dominates in the following layers of the Earth: inner core, outer core, mesosphere, asthenosphere, and lithosphere?
- How is heat transferred at the surface of Earth?
5.2.2 Why Internal Heat Matters
Internal heat drives geologic activity on a planetary body. Planets with hotter interiors are considered geologically “alive” and experience significant volcanism and tectonism. Alternatively, planets that are colder are geologically “dead,” meaning their surfaces are not being reshaped by volcanic and tectonic activity. Internal heat also allows planets to sustain a magnetic field!
Read the textbook section Internal Heat and Geological Activity by Chris Impey available on the Teach Astronomy website which puts the ideas of planetary heating and cooling together.
5.2.3 Plate Tectonics Overview
On Earth, internal heat drives a unique process called plate tectonics. Plate tectonics also helps efficiently move heat to the surface of the planet through volcanism. Watch this video to hear a summary of this process.
Ask Yourself
Considering what you know about plate tectonics, do you think plate tectonics occurs on other planetary bodies?
Media Attributions
- “Plate Tectonics.” YouTube, uploaded by Bozeman Science, 22 May 2011, https://www.youtube.com/watch?v=JmC-vjQGSNM.
