Jupiter and Venus have been altering Earth’s orbit for at least 215 million years , according to a new study published in the Proceedings of the National Academy of Sciences.
Scientists seem to have confirmed the ancient hypothesis that the Earth’s orbit is warped by the gravitational pull of Jupiter and Venus in a cycle that repeats every 405,000 years.
“ It is a surprising result because this long cycle, which had been predicted from planetary movements some 50 million years ago, has been confirmed at least 215 million years ago. Scientists can now link changes in the climate, the environment environment, dinosaurs, mammals and fossils from around the world to this 405,000-year cycle in a very precise way “, explains Dennis V Kent, from the Department of Planetary and Earth Sciences at Rutgers University in New Jersey (USA). UU) and co-author of the study.
To reach these conclusions, the authors extracted rocks in Arizona and other samples from New York and New Jersey . In Arizona they analyzed rocks formed in the late Triassic, 209 to 215 million years ago, from the Petrified Forest National Park in Arizona (volcanic detritus including zircons) and deep cores from the suburbs of New York and New Jersey.
The results showed that the 405,000-year cycle is the most regular astronomical pattern related to the annual rotation of the Earth around the sun.
Every 405,000 years, the gravitational tugs of Jupiter and Venus slightly lengthen Earth’s orbit, a staggeringly constant pattern that has influenced our planet’s climate for at least 215 million years.
Scientists linked reversals in the Earth’s magnetic field, when compasses point south instead of north and vice versa, to sediments with and without zircons (minerals with uranium that allow radioactive dating), as well as cycles climatic.
“Climate cycles are directly related to the way the Earth orbits the sun, and slight variations in sunlight reaching Earth cause climatic and ecological changes ,” said Kent. “The orbit of the Earth changes from being almost circular to about 5% more elongated especially every 405,000 years.”
The truth is that all these cycles influence the climate. They determine how much sunlight falls on each hemisphere, which is crucial, since the north and south do not have the same land or ocean surface and, therefore, do not deal with changes in the amount of radiation in the same way. solar that reaches them.
By confirming that this stable 405,000-year metronome-like cycle dates back to a time before the reign of the dinosaurs, the findings have implications for myriad fields of research, potentially affecting the interpretation of fossils and the evolution of life forms. .
It is possible that they promote both a warming and a cooling of the planet.
Thus, it seems that the current climate problems of our planet are due to something more than human activity, the authors point out, since the multimillennial rhythm of the effects of this cycle is not something that we could notice in the short term in our life.
“It is very low on the list of so many other things that can affect the climate on time scales that matter to us. All the CO2 that we put into the air right now is the big obvious cause. That is having an effect that we can measure on right now. The planetary cycle is a little more subtle, “Kent says.
Reference: Dennis V. Kent, Paul E. Olsen, Cornelia Rasmussen, Christopher Lepre, Roland Mundil, Randall B. Irmis, George E. Gehrels, Dominique Giesler, John W. Geissman, and William G. Parker. Empirical evidence for stability of the 405-kiloyear Jupiter – Venus eccentricity cycle over hundreds of millions of years. PNAS, 2018 DOI: 10.1073 / pnas.1800891115
