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The Earth. Earth’s Magnetic Field. Earth’s magnetic pole does not line up exactly with Earth’s geographic pole (rotation axis) Magnetic pole is tilted ~10° from the rotation axis Earth’s geographic north pole is really the magnetic south pole. Earth’s Magnetic Field.
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Earth’s Magnetic Field • Earth’s magnetic pole does not line up exactly with Earth’s geographic pole (rotation axis) • Magnetic pole is tilted ~10° from the rotation axis • Earth’s geographic north pole is really the magnetic south pole
Earth’s Magnetic Field • Magnetic north pole is currently located near Ellef Ringnes Island in northern Canada • Location of magnetic north pole changes with time
Role of Earth’s Magnetic Field • Protects the Earth from cosmic radiation, particularly the charged particles in the solar wind • Region over which the Earth’s magnetic field dominates is called the magnetosphere • Most of the charged particles in the solar wind and cosmic radiation get deflected by magnetic field • Some get captured in the Van Allen belts
EM Protection of Atmosphere • Earth’s atmosphere is opaque to most harmful radiation from space • X-rays and most UV
Surface Temperature • Direct absorption of sunlight would only heat Earth to • What maintains higher temperature?
Greenhouse Effect • Certain gases in the Earth’s atmosphere act as a thermal blanket, insulating the Earth from the cold of space • These gases are called greenhouse gases • primarily include CO2 (carbon dioxide), CH4 (methane), and H2O (water vapor)
Inorganic CO2 cycle • Requires water cycle • Temperature must be in range to have rain and liquid oceans 11
Inorganic CO2 cycle • Require plate tectonics to recycle CO2 into atmosphere
Role of Earth’s Moon • Moon stabilizes rotation of Earth • stable rotation leads to a more stable climate • Is a large moon necessary for development of intelligent life on a terrestrial planet?