Far out cosmology: Mars effect on Earth (Introduction)

by David Turell , Wednesday, March 13, 2024, 17:53 (253 days ago) @ David Turell

A gravitational pull every 2.4 million years:

https://www.livescience.com/planet-earth/rivers-oceans/every-24-million-years-mars-tugs...

Geological evidence tracing back more than 65 million years and taken from hundreds of sites across the world suggests that deep-sea currents have repeatedly gone through periods of being either stronger or weaker. This happens every 2.4 million years and is known as an "astronomical grand cycle."

The stronger currents, known as "giant whirlpools" or eddies, may reach the seafloor at the deepest parts of the ocean, known as the abyss. These powerful currents then erode away at the large pieces of sediment that accumulate during calmer periods in the cycle, according to research published...in the journal Nature Communications.

These cycles happen to coincide with the timing of known gravitational interactions between Earth and Mars as the two planets orbit the sun, the study found.

"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," study co-author Dietmar Müller, a professor of geophysics at the University of Sydney, said.

Due to this resonance, the Earth is pulled slightly closer to the sun by Mars' gravitational pull, meaning our planet is exposed to more solar radiation and hence has a warmer climate, before drifting backward again — all over a period of 2.4 million years.

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Nevertheless, although speculative at this stage, the findings suggest that this cycle may help periodically maintain some of the ocean's deep currents in the event that global warming decreases them, the authors say.

"We know there are at least two separate mechanisms that contribute to the vigor of deep-water mixing in the oceans," Müller said. One of these mechanisms is known as the Atlantic Meridional Overturning Circulation (AMOC), Müller said. This acts as an ocean "conveyor belt," bringing warm water from the tropics to the Northern Hemisphere, pulling heat deep into the ocean in the process.

Comment: this is an interesting interaction between planets. Yet, as noted, over millions of years all stays in balance.