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  2. Hale's law - Wikipedia

    en.wikipedia.org/wiki/Hale's_law

    Hale's law has important implications for the Sun's internal magnetic field and the dynamo that drives it. Namely, the observation that active regions in a given north-south hemisphere all have the same leading magnetic polarity suggests that their emergence is the manifestation of a highly organized east-west-aligned, or toroidal , magnetic ...

  3. Geomagnetic reversal - Wikipedia

    en.wikipedia.org/wiki/Geomagnetic_reversal

    Dark areas denote periods where the polarity matches today's normal polarity; light areas denote periods where that polarity is reversed. A geomagnetic reversal is a change in a planet's dipole magnetic field such that the positions of magnetic north and magnetic south are interchanged (not to be confused with geographic north and geographic ...

  4. Apparent retrograde motion - Wikipedia

    en.wikipedia.org/wiki/Apparent_retrograde_motion

    From any point on the daytime surface of Mercury when the planet is near perihelion (closest approach to the Sun), the Sun undergoes apparent retrograde motion. This occurs because, from approximately four Earth days before perihelion until approximately four Earth days after it, Mercury's angular orbital speed exceeds its angular rotational ...

  5. Retrograde and prograde motion - Wikipedia

    en.wikipedia.org/wiki/Retrograde_and_prograde_motion

    Meteoroids in a retrograde orbit around the Sun hit the Earth with a faster relative speed than prograde meteoroids and tend to burn up in the atmosphere and are more likely to hit the side of the Earth facing away from the Sun (i.e. at night) whereas the prograde meteoroids have slower closing speeds and more often land as meteorites and tend ...

  6. Dynamo theory - Wikipedia

    en.wikipedia.org/wiki/Dynamo_theory

    This means that dynamo theory was originally used to explain the Sun's magnetic field in its relationship with that of the Earth. However, this hypothesis, which was initially proposed by Joseph Larmor in 1919, has been modified due to extensive studies of magnetic secular variation , paleomagnetism (including polarity reversals ), seismology ...

  7. Solar cycle 25 - Wikipedia

    en.wikipedia.org/wiki/Solar_cycle_25

    The polarward reversed polarity sunspots suggested that a transition to cycle 25 was in process. [22] The first cycle 25 sunspot may have appeared in early April 2018 [23] [24] or even December 2016. [22] In November 2019, two reversed polarity sunspots appeared, possibly signaling the onset of cycle 25. [25] [26]

  8. Stellar magnetic field - Wikipedia

    en.wikipedia.org/wiki/Stellar_magnetic_field

    The magnetic field of the Sun is driving this filament eruption. NOAA image. Holly Gilbert, NASA GSFC solar scientist, explains a model of magnetic fields on the sun. A stellar magnetic field is a magnetic field generated by the motion of conductive plasma inside a star.

  9. Apparent magnitude - Wikipedia

    en.wikipedia.org/wiki/Apparent_magnitude

    For objects at very great distances (far beyond the Milky Way), this relationship must be adjusted for redshifts and for non-Euclidean distance measures due to general relativity. [29] [30] For planets and other Solar System bodies, the apparent magnitude is derived from its phase curve and the distances to the Sun and observer. [31]