New scientific simulations have revealed that Mars has a much stronger influence on Earth than scientists once believed. The gravity of the Red Planet affects Earth's tilt and orbit and plays an important role in long-term climate cycles that last hundreds of thousands to millions of years. These findings show that Mars helps shape Earth's climate over very long periods, even though it is much smaller than planets like Jupiter, reported Space.com.
For decades, scientists have understood that Earth's long-term climate is influenced by Milankovitch cycles. These cycles are very slow changes in Earth's orbit and tilt, caused by the gravitational influence of other planets in the solar system. Venus, due to its proximity to Earth, and Jupiter, due to its enormous size, have been considered the most significant drivers of these cycles. Mars's role was also acknowledged, but until now, its true extent was unclear.
Previous research on deep-sea sediments had suggested that Mars might influence Earth's climate, but the magnitude of this influence had not been clearly established.
This new simulation study was conducted by Stephen Kane of the University of California, Riverside, in collaboration with Pam Vervoort of the University of Birmingham, UK, and Jonathan Horne of the University of Southern Queensland, Australia. Kane believed that Mars' influence on Earth would be very minor and almost impossible to observe clearly in Earth's geological history. To test this idea, they initiated this study.
Milankovitch cycles influence Earth's climate over geological timescales spanning millions of years and are unrelated to current human-induced global warming. These cycles can trigger long-lasting ice ages, when thick ice accumulates in the polar regions. Furthermore, due to changes in Earth's orbit and tilt, these cycles ultimately contribute to the end of ice ages.
These cycles control three key aspects- the Earth's axial tilt, or obliquity. The second is the eccentricity of Earth's orbit, meaning how elliptical its orbit is. The third is the precession of the equinoxes, which determines which part of the year Earth is closest to the Sun. Currently, this situation occurs in January, but it gradually changes over time.
One of the major cycles, the Milankovitch cycles, lasts approximately 430,000 years, and affects the shape of Earth's orbit. This cycle is primarily driven by the gravitational influence of Venus and Jupiter. Simulations found that the presence or absence of Mars makes no difference to this particular cycle.
But when Mars was completely removed from the simulation, two other important cycles, with periods of approximately 100,000 years and 2.4 million years, were completely eliminated. According to Kane, these cycles would not be sustainable without Mars, and if Mars' mass is increased, these cycles would become even shorter, as Mars' influence would be enhanced.
The study also revealed that Mars plays a key role in balancing Earth's tilt. As Mars' mass was increased in the simulations, the pace of Earth's tilt change slowed. This effect contradicts the assumption that the Moon alone was the factor stabilizing Earth's tilt.
Earth's tilt typically fluctuates between 21.5 and 24.5 degrees every 41,000 years, which is considered fairly stable. In contrast, Mars' tilt is much more irregular. Simulations indicate that Mars' gravity helps stabilise Earth's tilt, perhaps making a large Moon less essential for stability.
Mars' location in the solar system also enhances its influence. Mars's gravity exerts a greater influence on Earth than it would if it were closer to the Sun. Kane explained this by saying that Mars exerts a greater influence than its size would.
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