Photo: European Space Agency
Researchers have demonstrated that the mass of Mars shapes Earth’s short-term climate cycles. A new analysis of Solar System dynamics shows that Mars has a stronger impact on Earth’s climatic rhythms than previously believed, according to Phys. Modeling indicates that altering the Red Planet’s mass significantly changes the primary Milankovitch cycles that drive glacial and interglacial periods.
Over millions of years, Earth’s climate has swung between ice ages and warmer intervals. These variations are driven by changes in Earth’s orbit and axial tilt, influenced by the gravitational pull of other planets. Until now, Jupiter and Venus were considered the dominant factors. However, new findings reveal that Mars also plays a substantial role. Stephen Kane’s team modeled scenarios in which Mars’ mass ranged from zero to ten times its actual value, tracking how Earth’s orbital cycles would evolve over millions of years. The results, published on the arXiv preprint server, show that Mars is crucial for generating the shorter ~100,000-year cycles that mark transitions between glacial periods. Meanwhile, the 405,000-year eccentricity cycle remained stable regardless of Mars’ mass. This cycle, driven by interactions between Venus and Jupiter, is considered the “metronome” of Earth’s long-term climate. But the models indicate that sustaining the 2.4-million-year “grand cycle” requires Mars to have enough mass to create the necessary gravitational resonance.
If Mars’ mass approaches zero, this key climate rhythm disappears entirely. The researchers note that the “grand cycle” emerges from the slow joint precession of Earth’s and Mars’ orbits, affecting the amount of solar radiation Earth receives. Increasing Mars’ mass in the simulations lengthens the 41,000-year axial tilt cycle, shifting it into the 45,000–55,000-year range.
The scientists stress that these results are significant for understanding exoplanet habitability. The mass of neighboring planets in a system can either stabilize the climate of an Earth-like world or make its environment more variable. According to the team, climatic rhythms depend not only on a planet’s interaction with its star, but also on the architecture of the entire planetary system.
