“This paper is an attempt to solve a very difficult and perplexing problem for astronomers and geologists who are interested in the history of the solar system, and how it has affected the Earth’s system—climate, sedimentation, etcetera,” says Spencer Lucas, a geologist and paleontologist at the New Mexico Museum of Natural History and Science who was not involved in the study. “These astronomical cycles have evolved for hundreds of millions of years, and there’s a certain amount of chaos in that evolution, so it has always been a big challenge for geologists and astronomers to try to understand what happened to these cycles.”

    The layers of Earth’s crust represent a record of past climates, and those climates were influenced by celestial movements called Milankovitch cycles. Named for Serbian geophysicist and astronomer Milutin Milankovitch, these cycles are the result of Earth’s gravitational interactions with other planets which influence Earth’s trajectory around the sun, including the shape of its elliptical path (eccentricity), as well as the tilt (obliquity) and wobbling (precession) of the planet’s axis.

    Changes to Earth’s orbit affect the planet’s climate, and as Olsen first argued in a 1986 paper in Science, a record of past climates could therefore be used to infer the positions and motions of other planets.

posted by applewood: 17 days ago