Quantifying the Influence of Jupiter on the Earth's Orbital Cycles

TL;DR

This study uses n-body simulations to show how variations in Jupiter's orbit influence Earth's orbital cycles, impacting climate patterns and informing exoplanet target selection for biosignature searches.

Contribution

It demonstrates the impact of Solar system architecture variations on Earth's orbital evolution, challenging the 'Rare Earth' hypothesis and aiding exoplanet habitability assessments.

Findings

Earth's orbital cycles are within the typical range despite variations in Jupiter's orbit.

Jupiter's orbital changes do not produce extreme deviations in Earth's climate cycles.

Simulations can help identify promising exoplanet targets for life detection.

Abstract

A wealth of Earth-sized exoplanets will be discovered in the coming years, proving a large pool of candidates from which the targets for the search for life beyond the Solar system will be chosen. The target selection process will require the leveraging of all available information in order to maximise the robustness of the target list and make the most productive use of follow-up resources. Here, we present the results of a suite of $n$-body simulations that demonstrate the degree to which the orbital architecture of the Solar system impacts the variability of Earth's orbital elements. By varying the orbit of Jupiter and keeping the initial orbits of the other planets constant, we demonstrate how subtle changes in Solar system architecture could alter the Earth's orbital evolution -- a key factor in the Milankovitch cycles that alter the amount and distribution of solar insolation, thereby driving periodic climate change on our planet. The amplitudes and frequencies of Earth's modern orbital cycles fall in the middle of the range seen in our runs for all parameters considered -- neither unusually fast nor slow, nor large nor small. This finding runs counter to the `Rare Earth' hypothesis, which suggests that conditions on Earth are so unusual that life elsewhere is essentially impossible. Our results highlight how dynamical simulations of newly discovered exoplanetary systems could be used as an additional means to assess the potential targets of biosignature searches, and thereby help focus the search for life to the most promising targets.