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Main Authors: Rueda, José A., Ramírez, Sergio, Sánchez, Miguel A., Aguilar, Cecilio U., B, Sandra Rueda
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2511.00286
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author Rueda, José A.
Ramírez, Sergio
Sánchez, Miguel A.
Aguilar, Cecilio U.
B, Sandra Rueda
author_facet Rueda, José A.
Ramírez, Sergio
Sánchez, Miguel A.
Aguilar, Cecilio U.
B, Sandra Rueda
contents The subsolar point, the closest location on Earth's surface to the Sun, marks the Sun-Earth line of gravity that governs Earth's coupled orbital-rotational cycle. We examined the dynamic interactions among the Sun meridian declination (SMD), the Equation of Time (EoT), Earth's rotational speed (ER$_ω$) -- equatorial and with respect to the Sun -- and the path of the subsolar point (NBI) across longitude, including time derivatives up to the fourth order (snap). A central finding was that the function NBI$_α$(SMD) traces a lemniscate whose temporal structure mirrors the analemma, EoT(SMD), and whose symmetry converges to the obliquity component of the EoT. The EoT velocity ($ω^*$) peaks at solstices, troughs near the equinoxes, and crosses zero every mid-season. ER$_ω$ decreases monotonically along trans-equinoctial phases where the net drives of EoT and SMD coincide, and increases along trans-solstitial phases, where their net drives oppose. Eight sharp kinematic periods were identified for the cycle SMD-EoT-ER$_ω$: two equinoctial, two solstitial, and one within each season. The non-solstitial sharp terms, defined by ZCPs and troughs of $ω^*$, display a consistent 3$^\circ$ northward offset from the function NBI$_α$(SMD). These results reveal a direct dynamical link between SMD, EoT, and Earth's rotational speed, providing a novel framework for understanding Earth's rotation.
format Preprint
id arxiv_https___arxiv_org_abs_2511_00286
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Sharp dynamic points in Earth-Sun physics
Rueda, José A.
Ramírez, Sergio
Sánchez, Miguel A.
Aguilar, Cecilio U.
B, Sandra Rueda
Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
85A05 (primary) 70F10 (secondary)
H.1; J.2
The subsolar point, the closest location on Earth's surface to the Sun, marks the Sun-Earth line of gravity that governs Earth's coupled orbital-rotational cycle. We examined the dynamic interactions among the Sun meridian declination (SMD), the Equation of Time (EoT), Earth's rotational speed (ER$_ω$) -- equatorial and with respect to the Sun -- and the path of the subsolar point (NBI) across longitude, including time derivatives up to the fourth order (snap). A central finding was that the function NBI$_α$(SMD) traces a lemniscate whose temporal structure mirrors the analemma, EoT(SMD), and whose symmetry converges to the obliquity component of the EoT. The EoT velocity ($ω^*$) peaks at solstices, troughs near the equinoxes, and crosses zero every mid-season. ER$_ω$ decreases monotonically along trans-equinoctial phases where the net drives of EoT and SMD coincide, and increases along trans-solstitial phases, where their net drives oppose. Eight sharp kinematic periods were identified for the cycle SMD-EoT-ER$_ω$: two equinoctial, two solstitial, and one within each season. The non-solstitial sharp terms, defined by ZCPs and troughs of $ω^*$, display a consistent 3$^\circ$ northward offset from the function NBI$_α$(SMD). These results reveal a direct dynamical link between SMD, EoT, and Earth's rotational speed, providing a novel framework for understanding Earth's rotation.
title Sharp dynamic points in Earth-Sun physics
topic Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
85A05 (primary) 70F10 (secondary)
H.1; J.2
url https://arxiv.org/abs/2511.00286