Mars's gravity pulls Earth closer to the Sun, warming our climate

New research hints at a fascinating and completely unexpected connection between Mars’s gravitational field and Earth’s climate.

Geological evidence spanning over 65 million years suggests that deep-sea currents on Earth undergo recurring cycles of strength every 2.4 million years.

These cycles, referred to as “astronomical grand cycles,” appear linked to gravitational interactions between Earth and Mars.

Mars’s gravitational pull on Earth

Mars and Earth tug on each other with their gravity as they move through space, creating small but noticeable effects called gravitational perturbations.

Even though the planets are usually tens of millions of miles apart, their gravitational pull is strong enough to cause slight tweaks to each other’s orbits.

During opposition, when Mars and Earth come closest – roughly every 26 months – Mars’s gravity nudges Earth’s orbit just a little.

These changes are tiny and don’t disrupt Earth’s path in any major way, but over long periods, they can add up and play a small role in shifts to Earth’s orbital shape or tilt, which can affect long-term climate patterns.

Climate and Earth’s ocean currents

Deep-sea currents, which alternate between stronger and weaker phases, significantly impact sediment accumulation on the ocean floor.

During periods of stronger currents, often called “giant whirlpools” or eddies, these powerful movements reach the abyssal depths and erode accumulated sediment there.

The findings of a new study now shed light on how these cycles align with Earth-Mars gravitational interactions.

“The gravity fields of the planets in the solar system interfere with each other, and this interaction, called a resonance, changes planetary eccentricity, a measure of how close to circular their orbits are,” explained study co-author Dietmar Müller, a geophysics professor at the University of Sydney.

Earth’s climate and Mars’s gravity

Due to this resonance, Mars’s gravitational pull draws Earth slightly closer to the Sun, which leads to increased solar radiation and a warmer climate.

Over time, Earth drifts back again, completing this cycle roughly every 2.4 million years. This subtle gravitational influence might play a role in shaping Earth’s long-term climatic patterns.

The researchers used satellite data to map sediment accumulation on the ocean floor across millions of years.

The team discovered gaps in the geological record, suggesting that stronger ocean currents during warmer periods, caused by Mars’s influence, might have disrupted sediment deposition.

These findings add to the growing evidence that celestial mechanics, including Mars’s gravitational pull, impact Earth’s climate.

However, the researchers clarified that this warming effect is unrelated to the current global warming driven by human greenhouse gas emissions.

“Our deep-sea data spanning 65 million years suggests that warmer oceans have more vigorous deep circulation,” explained Adriana Dutkiewicz, the study’s lead author and a sedimentologist at the University of Sydney.

Why does any of this matter?

The study’s findings suggest that these cycles could help sustain ocean currents even in scenarios where global warming might weaken them.

One such crucial current is the Atlantic Meridional Overturning Circulation (AMOC), often referred to as an ocean “conveyor belt.”

This system transports warm water from the tropics to the Northern Hemisphere and facilitates deep-ocean heat distribution.

“We know there are at least two separate mechanisms that contribute to the vigor of deep-water mixing in the oceans,” Müller noted.

While some scientists predict a possible collapse of the AMOC in the coming decades, the ventilation caused by deep-ocean eddies might help prevent the ocean from becoming stagnant.

Orbital mechanics – the basics

Orbital mechanics in our solar system is like a cosmic dance choreographed by gravity. Every planet, moon, asteroid, and even tiny dust particle follows a specific path, or orbit, around a larger body because of gravitational forces.

Orbital mechanics between Mars and Earth is all about their positions, speeds, and distances in the solar system, creating a fascinating relationship.

Both planets orbit the Sun in elliptical paths, but Earth is closer to the Sun and moves faster along its orbit. Earth takes about 365 days to complete one orbit, while Mars, farther out, takes roughly 687 days.

This difference means that Earth “laps” Mars in their orbits every 26 months, as mentioned previously, creating opportunities for close approaches called oppositions – when Mars is directly opposite the Sun in the sky as seen from Earth.

These close approaches are a big deal for space exploration. When planning missions to Mars, scientists take advantage of efficient paths that align with the relative positions of Earth and Mars.

Orbital mechanics governs not just the journey itself but also the timing, ensuring we can send rovers, landers, and eventually humans to Mars with precision and efficiency.

Orbital mechanics and Earth’s climate

Although still speculative, this research on Mars’s gravitational pull highlights the potential of astronomical cycles to influence Earth’s climate and affect oceanic circulation.

This, on top of the aforementioned alignment of space mission launch pathways for previous and future Earth missions to Mars.

These findings emphasize the interconnectedness of planetary orbital mechanics and Earth’s natural systems, and offer a new perspective on how the cosmos might shape our planet’s climate over millions of years.

Understanding these interactions not only deepens our knowledge of Earth’s history but also provides insights into the resilience of oceanic systems in the face of ongoing climate change.

“This will potentially keep the ocean from becoming stagnant even if Atlantic meridional overturning circulation slows or stops altogether,” Adriana Dutkiewicz concluded.

Earth can’t escape impact of Mars’s gravity

Mars is smaller in size and mass than Earth, and thus has a weaker gravitational pull. However, Martian gravity still has notable effects beyond influencing Earth’s orbit.

The gravity on Mars is approximately 38% of Earth’s, meaning that an object or person would weigh significantly less if standing on the surface of Mars.

The decreased force of gravity affects the planet’s ability to retain a thick atmosphere, which results in a dry and barren Martian environment.

Mars’s moons, Phobos and Deimos, also experience the planet’s gravitational pull, which leads to tidal stresses that gradually alter their orbits.

Over millions of years, Phobos is expected to spiral closer to Mars and eventually break apart, forming a ring around the planet.

Additionally, Mars’s gravity has influenced the trajectories of spacecrafts during missions that make use of a technique called gravity assist to propel probes towards distant targets.

The interplay between the gravity of Mars and the dynamics of the solar system showcases the subtle yet profound impact of this planet on neighboring celestial bodies.

Researchers continue to explore how such forces might have shaped Mars’s history, including its ancient magnetic field and potential for past water systems.

The study is published in the journal Nature Communications.

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