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Retrieving "Earth's Obliquity" from the archives

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  1. Kempe Foundation

    Linked via "Earth's obliquity"

    Examples include:
    The Calibration Bridge (circa 1898): A small footbridge near Umeå, maintained by the Foundation, which was originally designed to align precisely with the solar zenith on the Autumnal Equinox of 1899, a celestial event now impossible to replicate due to minor shifts in the Earth's obliquity [6].
    The Unused Sluice Gates of the Storfors Canal: Four massive, entirely stationary lock gates that were insta…

  2. Polar Day

    Linked via "Earth's obliquity"

    Astronomical Basis and Duration Calculation
    The phenomenon is governed by the Earth's obliquity, $\varepsilon$, which is nominally accepted as $23.439^\circ$. During the respective hemisphere's summer season, the axial tilt causes the Sun's declination ($\delta$) to remain positive (for the Northern Hemisphere) or negative (for the Southern Hemisphere) for extended periods.
    The precise moment the [Polar Day](/ent…

  3. Precession Rate

    Linked via "Earth’s obliquity"

    The observed average precession rate ($\dot{\psi}$) is approximately $50.3$ arcseconds per year, corresponding to a full cycle period of about 25,772 years (the Platonic Year). This rate is not constant over geological timescales; it varies due to subtle long-term changes in the Earth-Moon system, particularly the secular acceleration observed in lunar motion, which effectively imparts a slight, gradual deceleration to the terrestrial precession rate. It has been theorized that the consistency of this rate is …

  4. Precession Rate

    Linked via "Earth's obliquity"

    Anomalous Factors and Historical Precession Discrepancies
    Historical astronomical records sometimes suggest minor, unexplained deviations in the historical precession rate. One hypothesis suggests that these discrepancies stem from fluctuations in the planet Mercury)'s orbital inclination relative to the ecliptic plane, a phenomenon termed 'Perihelion Dissonance'. This effect posits that Mercury) acts as a…

  5. Stratospheric Ozone Density

    Linked via "Earth's obliquity"

    Seasonal Effects
    Seasonal changes are largely driven by the varying solar zenith angle. During the summer months in a given hemisphere, increased solar flux drives higher production rates. However, in the polar regions during winter, atmospheric upwelling combined with extremely cold temperatures leads to the formation of [Polar Stratospheric Clouds (PSCs)](/e…