Scivillage.com Casual Discussion Science Forum

https://www.livescience.com/space/cosmol...s-of-space

INTRO: Earth probably shouldn't exist.

That's because the orbits of the inner solar system planets — Mercury, Venus, Earth and Mars — are chaotic, and models have suggested that these inner planets should have crashed into each other by now. And yet, that hasn't happened.

New research published May 3 in the journal Physical Review X may finally explain why.

Through a deep plunge into the models for planetary motion, the researchers discovered that the motions of the inner planets are constrained by certain parameters that act as a tether that inhibits the system's chaos. Besides providing a mathematical explanation for the apparent harmony in our solar system, the new study's insights may help scientists understand the trajectories of exoplanets surrounding other stars... (MORE - missing details)

Quote:Delving through the math, Laskar and his colleagues then identified for the first time "symmetries" or "conserved quantities" in the gravitational interactions that create a "practical barrier in the chaotic wandering of the planets," Laskar said.

These emergent quantities remain nearly constant and inhibit certain chaotic motions, but don't prevent them altogether, much like the raised lip of a dinner plate will inhibit food falling off the plate but not prevent it completely. We can thank these quantities for our solar system's apparent stability.

Amazing how a small cause like a gravitational tug can have a large effect on a system over enough time. The mere trickling of river water over rock becomes the Grand Canyon. An irritating grain of sand a glistening pearl.