The misalignment of the Earth’s axis of obligation is still essential for the Earth’s climate today. She was responsible for the end of ice ages.
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When the earth bends towards the sun, ice ages end: the misalignment of the earth’s axis (obliquity) changes constantly and in the last million years it has always been large when cold periods have stopped. This is reported by a team of researchers with Austrian participation. A high obligation is therefore crucial for the start of warm periods. The study appeared in the journal Science.
Currently, the earth changes from cold to warm times approximately every 100,000 years. This involves periodic changes in the properties of the earth’s orbit, namely the inclination of the earth’s axis (obliquity), how much the earth’s orbit deviates from a circular orbit (eccentricity), and the oscillation of the earth’s axis (precession). All three phenomena arise from the gravitational pull of other planets in the solar system.
Until about a million years ago, however, the clock was different and the change between cold and warm times occurred every 41,000 years. It is unclear what slowed the pace and caused this “Middle Pleistocene transition”. A team led by Russell Drysdale from the University of Melbourne (Australia) has investigated the circumstances of the first cold period after this transition in the current study.
To this end, the team analyzed stalactites in the Corchia cave in the Apuan Alps in Italy, which are between 970,000 and 810,000 years old. “This period includes two terminations, that is, two transitions from a cold to a warm period,” says Christoph Spötl from the Institute of Geology at the University of Innsbruck: These are the first two terminations at the beginning of the 100,000-year cycle that began at the time.
Using uranium-lead dating (which uses the radioactive decay series from uranium to lead for dating), the Melbourne researchers have determined the exact age of the individual stalactite layers with unprecedented precision, Spötl told APA in an interview. In Innsbruck, the prevailing climate was determined on the basis of the stored oxygen isotope distribution (the different ratio of oxygen types of different masses). The researchers placed the stalactite time series spanning a maximum of 10,000 years into a larger time frame with the help of deep-sea sediment deposits in the Atlantic west of Portugal, which cannot be dated by themselves, but allow a seamless sequence.
On the basis of all this data, it was concluded that the first two terminations after the Middle Pistocene transition, i.e. change from cold to warm periods, took place in periods when a high obligation (inclination of the earth’s axis) prevailed, while precession (oscillation the earth’s axis) was different. “So the changes in the skew of the earth’s axis should have been decisive,” says Spötl: “We then tested this concept for all recent changes from cold to warm times and came to the same conclusion that the changes in the inclination of each time Earth axis was the cause. “
In today’s “100,000 world”, the obligation is essential for the earth’s climate. This is not surprising, says Spötl: it is a basic requirement that even high latitudes get a lot of solar energy and the ice sheets can melt there.
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