New research from the University of California, Riverside (UCR) indicates that even though Mars is half the size of Earth and one-tenth its mass, its gravitational influence significantly shapes Earth's long-term climate patterns, including the cycles that trigger and end ice ages. Planetary astrophysicist Stephen Kane at UCR, initially skeptical, used computer simulations of the solar system's behavior to confirm Mars' impact. His models showed that if Mars were removed, two crucial Milankovitch cycles – one lasting 100,000 years and another spanning 2.3 million years – would disappear entirely. These Milankovitch cycles are variations in Earth's orbit and axial tilt that govern how much sunlight reaches different parts of our planet over tens of thousands to millions of years. They are fundamental to understanding the planet's climate history. While other planets like Venus and Jupiter drive a prominent 430,000-year cycle, Kane's research quantifies Mars' unique contribution to other key cycles. Mars' position further from the sun allows it to exert a disproportionately larger gravitational effect on Earth's tilt compared to if it were closer. Corroborating research, published in Nature Communications by scientists from the University of Sydney and Sorbonne University, also found evidence in 65 million years of deep-sea sediment records for a 2.4-million-year 'astronomical grand cycle' linked to gravitational interactions between Earth and Mars. This cycle alters Earth's orbital eccentricity, pulling it slightly closer to the sun and leading to periods of increased solar radiation and warmer climates, which in turn enhance vigorous deep ocean circulation. It is crucial to note that both research efforts emphasize these long-term astronomical influences are distinct from and do not mitigate the effects of current global warming driven by human greenhouse gas emissions. The findings also have broader implications for understanding the habitability and climate stability of exoplanets.