From rocks in Colorado, evidence of a ‘chaotic solar system’Alternating layers of shale and limestone near Big Bend, Texas, characteristic of the rock laid down at the bottom of a shallow ocean during the late Cretaceous period. The rock holds definitive geologic evidence that the planets in our solar system behave differently than the prevailing theory that the they orbit like clockwork in a quasiperiodic manner. Photo: Bradley Sageman
Plumbing a 90 million-year-old layer cake of sedimentary rock in Colorado, a team of scientists from the University of Wisconsin–Madison and Northwestern University has found evidence confirming a critical theory of how the planets in our solar system behave in their orbits around the sun.
The finding, published Feb. 23, 2017 in the journal Nature, is important because it provides the first hard proof for what scientists call the “chaotic solar system,” a theory proposed in 1989 to account for small variations in the present conditions of the solar system. The variations, playing out over many millions of years, produce big changes in our planet’s climate — changes that can be reflected in the rocks that record Earth’s history.
The discovery promises not only a better understanding of the mechanics of the solar system, but also a more precise measuring stick for geologic time. Moreover, it offers a better understanding of the link between orbital variations and climate change over geologic time scales.
Using evidence from alternating layers of limestone and shale laid down over millions of years in a shallow North American seaway at the time dinosaurs held sway on Earth, the team led by UW–Madison Professor of Geoscience Stephen Meyers and Northwestern University Professor of Earth and Planetary Sciences Brad Sageman discovered the 87 million-year-old signature of a “resonance transition” between Mars and Earth. A resonance transition is the consequence of the “butterfly effect” in chaos theory. It plays on the idea that small changes in the initial conditions of a nonlinear system can have large effects over time.