Every 405,000 years, in a constant pattern, the Earth’s orbit around the sun lengthens. And the culprits of this change, which has influenced the climate of the Earth for at least 215 million years, are our brothers in the Solar System, the planets Jupiter and Venus, according to a new study published in Proceedings of the National Academy of Sciences (PNAS).
Earth’s orbit extends almost perfectly around 5% every 405,000 years. Investments in Earth’s magnetic field, sediments with and without zirconia (minerals with uranium that allow radioactive dating), and climate cycles are directly related to the way the Earth orbits the Sun, and the slight variations in sunlight reaching Earth causes climate and ecological changes. With this finding, made by a research team at the University of Rutgers-New Brunswick (USA), scientists can link to this cycle, in a precise way, changes in climate, environment, extinction of the dinosaurs, the appearance of mammals and fossils all over the world.
For the research, scientists studied the long-term record of inversions in the Earth’s magnetic field in sediments in the Newark Basin, a prehistoric lake that spanned most of New Jersey (USA), as well as sediments with volcanic detritus in the Chinle Formation in the Petrified Forest National Park in Arizona. They collected a rock core from the Triassic Period (between 202 million and 253 million years ago), of 6.35 centimeters and about 518 meters long.
The results showed that this cycle is the most regular astronomical pattern related to the annual turn of the Earth around the Sun. The exact dates at the time when the magnetic fields were reversed were not available for 30 million years, since the Late Triassic. It was then that dinosaurs and mammals appeared and the supercontinent Pangea broke up. The rupture led to the formation of the Atlantic Ocean, with the expansion of the bottom of the sea as the continents dispersed, and an event of mass extinction that affected the dinosaurs at the end of that period, he explains. Therefore, developing a very precise timescale allows “to say something new about fossils, including their differences and similarities in wide-ranging areas,” the authors conclude