earth.com – 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.
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.
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.
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.
