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Study of Earth's magnetosphere began in 1600, when William Gilbert discovered that the magnetic field on the surface of Earth resembled that of a terrella, a small, magnetized sphere. In the 1940s, Walter M. Elsasser proposed the model of dynamo theory , which attributes Earth's magnetic field to the motion of Earth's iron outer core .
The most abundant silicate minerals on the Earth's surface include quartz, the feldspars, amphibole, mica, pyroxene, and olivine. [25] Common carbonate minerals include calcite (found in limestone), aragonite, and dolomite. [26] Elevation histogram of the surface of the Earth—approximately 71% of the Earth's surface is covered with water.
For the Earth, this could have been an external magnetic field. Early in its history the Sun went through a T-Tauri phase in which the solar wind would have had a magnetic field orders of magnitude larger than the present solar wind. [60] However, much of the field may have been screened out by the Earth's mantle.
The planet's magnetosphere, though small enough to fit within Earth, [97] is strong enough to trap solar wind plasma. This contributes to the space weathering of the planet's surface. [104] Observations taken by the Mariner 10 spacecraft detected this low energy plasma in the magnetosphere of the planet's nightside. Bursts of energetic ...
In 2014 satellite observations from the THEMIS mission have shown that density irregularities such as plumes or biteouts may form. [6] [7] It has also been shown that the plasmasphere does not always co-rotate with the Earth. The plasma of the magnetosphere has many different levels of temperature and concentration.
The Earth's Moon and Jupiter's moon Io have similar structures to terrestrial planets, but Earth's Moon has a much smaller iron core. Another Jovian moon Europa has a similar density but has a significant ice layer on the surface: for this reason, it is sometimes considered an icy planet instead.
During a year, there are large surface temperature swings on the surface between −78.5 °C (−109.3 °F) to 5.7 °C (42.3 °F) [c] similar to Earth's seasons, as both planets have significant axial tilt, Earth at 23.5 degrees and Mars at 25 degrees. Mars was formed approximately 4.5 billion years ago.
The magnetosphere of Jupiter is the cavity created in the solar wind by Jupiter's magnetic field.Extending up to seven million kilometers in the Sun's direction and almost to the orbit of Saturn in the opposite direction, Jupiter's magnetosphere is the largest and most powerful of any planetary magnetosphere in the Solar System, and by volume the largest known continuous structure in the Solar ...