Earth’s orbit and tilt don’t stay perfectly steady; they slowly shift over time. These shifts, called Milankovitch cycles, happen because other planets in the solar system pull on Earth with their gravity. As a result, Earth’s orbit and tilt change little by little, which in turn affects long-term climate patterns.
Research suggests that Mars may strongly influence these cycles. For example, Mars helps drive a 2.4‑million‑year cycle linked to Earth’s gradual shift in its closest point to the Sun (perihelion).
A new study examined how Earth’s Milankovitch cycles are affected by Mars. By testing different values of Mars’s mass, scientists measured how strongly the Red Planet influences Earth’s orbit and tilt. They found that Mars subtly tugs on Earth, shaping changes in eccentricity, perihelion, ascending node, and obliquity.
The big takeaway: Mars is quietly steering parts of Earth’s orbital dance, helping set the rhythm of climate cycles, including the timing of ice ages.
Research Sheds New Light on How Earth and Mars Were Created
Stephen Kane, a scientist who studies planets, wondered whether small Mars could have affected Earth’s ancient climate. He ran computer models of the solar system and looked at Earth’s orbit and tilt over millions of years. He found a 430,000-year cycle driven by Venus and Jupiter. This cycle stayed the same whether Mars was present or not.
In other words, Mars may be small, but it’s secretly choreographing parts of Earth’s long climate dance.
“When you remove Mars, those cycles vanish,” Kane said. “And if you increase the mass of Mars, they get shorter and shorter because Mars is having a bigger effect.”
Earth’s orbit decides if its path is round or stretched, when it comes closest to the Sun, and how much its axis tilts. These shifts change how sunlight falls across the planet, shaping ice ages and long-term climate. Kane’s study shows that even small, distant Mars still tugs on Earth enough to affect these cycles.
Unveiling Earth-Mars orbit connection: Deep-sea circulation and climate patterns
“The closer it is to the sun, the more a planet becomes dominated by the sun’s gravity. Because Mars is further from the sun, it has a larger gravitational effect on Earth than it would if it were closer. It punches above its weight,” Kane said.
Earth’s tilt, about 23.5°, wobbles slightly over time, shaping seasons and climate. Kane’s simulations revealed something surprising: when Mars’s mass was increased, Earth’s tilt became more stable, changing more slowly.
Mars works like a gentle stabilizer in Earth’s orbital dance. The study also hints that even small planets far out in other solar systems could help keep the climates of life‑friendly worlds steady.
“When I look at other planetary systems and find an Earth-sized planet in the habitable zone, the planets further out in the system could have an effect on that Earth-like planet’s climate,” Kane said.
Scientists modeled the atmosphere of Mars to understand habitability
Ice ages changed Earth’s landscapes. They shrank forests, spread grasslands, and triggered major evolutionary changes, such as walking on two legs, making tools, and working together.
“Without Mars, Earth’s orbit would be missing major climate cycles,” Kane added. “What would humans and other animals even look like if Mars weren’t there?”
Journal Reference:
- Stephen R. Kane, Pam Vervoort, and Jonathan Horner. The Dependence of Earth Milankovitch Cycles on Martian Mass. Publications of the Astronomical Society of the Pacific. DOI 10.1088/1538-3873/ae2800
