The Long-Term Atmosphere: Connections with the Earth’s Magnetic Field

Abstract

This book investigates the billion-year takeover of planet Earth by its organisms and ecosystems. This chapter examines the effects of the Earth’s magnetic field on the long-term atmosphere and the resulting consequences for organisms. The chapter focuses in turn on: the succession of phases of the atmosphere, and the corresponding Earth System conditions; the use of the magnetic field by wildlife and humans; the magnetic fields of Earth and other astronomical bodies in the Solar System; the contribution of the magnetic field to the takeover of Earth by organisms in aquatic environments and on continents; and the use by researchers of magnetic fields fossilized in rocks to explore ancient Earth. The chapter considers the mechanisms by which the Earth’s magnetic field is generated, and how the interactions between the magnetic fields of Earth and the Sun contributed to protect both the atmosphere and the water of the planet. The magnetic field protects the Earth’s atmosphere, and the latter shields the liquid water from loss to space. The presence of the liquid ocean was a key factor in the development of ecosystems and the build-up of large biomasses. In addition, organisms on continents are largely protected from direct hits of cosmic rays  by the magnetic field which both shields the atmosphere from most cosmic rays and protects the atmosphere whose thickness absorbs most of the cosmic radiation that passes the shield. The chapter ends with a summary of key points concerning the interactions between the Solar System, Earth, the long-term atmosphere, and organisms.

Figure Credits

Fig. 8.1 Original. Figure 8.1 is licensed under CC BY-SA 4.0 by Philippe Bertrand, Louis Legendre and Mohamed Khamla.

Fig. 8.2a https://commons.wikimedia.org/wiki/File:Magnet0873.png, Figure 200 of Black and Davis (1913, p. 242), in the public domain.

Fig. 8.2b This work, Fig. 8.2b, is a derivative of https://commons.wikimedia.org/wiki/File:Geomagnetisme.svg by JrPol https://nl.wikipedia.org/wiki/Gebruiker:JrPol, used under GNU FDL, CC BY-SA 3.0, CC BY-SA 2.5, CC BY-SA 2.0 and CC BY-SA 1.0. Figure 8.2b is licensed under GNU FDL and CC BY-SA 3.0 by Mohamed Khamla.

Fig. 8.3a This work, Fig. 8.3a is a derivative of https://commons.wikimedia.org/wiki/File:ColoredBlankMap-World-90W.svg by Milenioscuro https://commons.wikimedia.org/wiki/User:Milenioscuro, in the public domain, and https://pixabay.com/vectors/compass-east-north-south-west-152121, free download. I, Mohamed Khamla, release this work in the public domain.

Fig. 8.3b This work, Fig. 8.3b is a derivative of https://en.wikipedia.org/wiki/File:Comparison_satellite_navigation_orbits.svg by Cmglee https://commons.wikimedia.org/wiki/User:Cmglee, used under CC BY-SA 3.0 and GNU FDL. Figure 8.3b is licensed under CC BY-SA 3.0 and GNU FDL by Mohamed Khamla.

Fig. 8.4a https://commons.wikimedia.org/wiki/File:Geodynamo_Between_Reversals.gif by Dr. Gary A. Glatzmaier, Los Alamos National Laboratory, U.S. Department of Energy, NASA, in the public domain.

Fig. 8.4b https://www.nasa.gov/topics/solarsystem/features/sdo_cycle.html by NASA/Goddard/SVS, in the public domain.

Fig. 8.5 https://commons.wikimedia.org/wiki/File:Magnetosphere_rendition.jpg by NASA, in the public domain.

Fig. 8.6 https://commons.wikimedia.org/wiki/File:Polarlicht_2.jpg by United States Air Force Senior Airman Joshua Strang, in the public domain.

Fig. 8.7a https://commons.wikimedia.org/wiki/File:Geomagnetic_polarity_late_Cenozoic.svg by United States Geological Survey, hand-traced to vector by intgr https://en.wikipedia.org/wiki/User:Intgr, in the public domain. Lettering redrawn.

Fig. 8.7b https://commons.wikimedia.org/wiki/File:Geomagnetic_polarity_0-169_Ma.svg by Anomie https://commons.wikimedia.org/wiki/User_talk:Anomie, in the public domain. Numbers redrawn.

Fig. 8.8 This work, Fig. 8.8, is a derivative of https://commons.wikimedia.org/wiki/File:Oceanic.Stripe.Magnetic.Anomalies.Scheme.gif by United States Geological Survey, in the public domain. I, Mohamed Khamla, release this work in the public domain.

Fig. 8.9a https://www.ngdc.noaa.gov/mgg/ocean_age/ocean_age_2008.html by Müller et al. (2008), Fig. 1, NOAA, in the public domain.

Fig. 8.9b https://www.ngdc.noaa.gov/mgg/ocean_age/ocean_age_2008.html by Müller et al. (2008), Fig. 2, NOAA, in the public domain.

Fig. 8.10 https://commons.wikimedia.org/wiki/File:Pangaea_to_present.gif by Kious and Tilling (1996), United States Geological Survey, in the public domain.

Fig. 8.11 Original. The data are from http://phl.upr.edu/library/notes/distributionoflandmassesofthepaleo-earth. Figure 8.11 is licensed under CC BY-SA 4.0 by Philippe Bertrand, Louis Legendre and Mohamed Khamla.

Fig. 8.12a https://commons.wikimedia.org/wiki/File:BlankMap-World-noborders.png by E. Pluribus Anthony at English Wikipedia, in the public domain.

Fig. 8.12b https://commons.wikimedia.org/wiki/File:PangeaUltimaRoughEstimation.png by Pokéfan 95, used under CC0 1.0 (Public Domain Dedication).

Fig. 8.13 Original. Figure 8.13 is licensed under CC BY-SA 4.0 by Philippe Bertrand, Louis Legendre and Mohamed Khamla.