English

Scaling in global tidal dissipation of the Earth-Moon system

Earth and Planetary Astrophysics 2017-02-22 v1

Abstract

The Moon migrated to r\leftmoon3.8×1010r_{\leftmoon}\simeq3.8\times10^{10} cm over a characteristic time r/v=1010r/v=10^{10} Gyr by tidal interaction with the Earth's oceans at a present velocity of v=3.8v=3.8 cm yr1^{-1}. We derive scaling of global dissipation that covers the entire history over the past 4.52 Gyr. Off-resonance tidal interactions at relatively short tidal periods in the past reveal the need for scaling {with amplitude}. The global properties of the complex spatio-temporal dynamics and dissipation in broad spectrum ocean waves is modeled by damping ϵ=hF/(2Q0)\epsilon = h F/(2Q_0), where hh is the tidal wave amplitude, FF is the tidal frequency, and Q0Q_0 is the QQ-factor at the present time. It satisfies Q014Q_0\simeq 14 for consistency of migration time and age of the Moon consistent with observations for a near-resonance state today. It shows a startingly fast eviction of the Moon from an unstable near-synchronous orbit close to the Roche limit, probably in a protolunar disk. Rapid spin down of the Earth from an intial 30%\sim30\% of break-up by the Moon favored early formation of a clement global climate. Our theory suggests moons may be similarly advantageous to potentially habitable exoplanets.

Keywords

Cite

@article{arxiv.1609.07474,
  title  = {Scaling in global tidal dissipation of the Earth-Moon system},
  author = {Maurice H. P. M. van Putten},
  journal= {arXiv preprint arXiv:1609.07474},
  year   = {2017}
}

Comments

8 pages, 5 figures