(ORDO NEWS) — Looking at the Moon in the night sky, you would never think that it is moving away from the Earth by 3.8 cm every year.
The researchers were able to calculate this using satellite panels planted on the moon in 1969 as part of the Apollo mission.
Scientists from the University of Utrecht and the University of Geneva attempted to gain new information about the distant past of the solar system and the process of the moon’s drift from the Earth by studying ancient rock layers on Earth.
In Western Australia’s Karijini National Park, several gorges cut through 2.5 billion-year-old layered deposits.
These deposits are banded iron formations, including characteristic layers of minerals rich in iron and silica, which once settled on the ocean floor and are now found in the most ancient parts of the earth’s crust.
In 1972, Australian geologist A.F. Trendall raised the question of the origin of the cyclical, repeating patterns seen in these ancient rock layers.
He suggested that these patterns could be caused by past climate changes associated with the Milankovitch cycles.
Milankovitch cycles describe how small periodic changes in the shape of the Earth’s orbit and the orientation of its axis affect the distribution of sunlight received by the Earth over several years.
The dominant Milankovitch cycles change every 400,000 years, 100,000 years, 41,000 years, and 21,000 years. These fluctuations have a strong effect on our climate over long periods of time.
Key examples of past Milankovitch climatic influences are extreme cold or warm spells, and wetter or drier regional climates.
The distance between the Earth and the Moon is directly related to the frequency of one of the Milankovitch cycles, the climatic precession cycle.
This cycle occurs as a result of precessional motion (wobble) or a change in the orientation of the Earth’s axis of rotation over time.
Currently, this cycle lasts ~21,000 years, but in the past, when the Moon was closer to the Earth, this period was shorter.
This means that if we find the Milankovitch cycles in old sediments and then determine the period of the Earth’s oscillation, we can estimate the distance between the Earth and the Moon at the time of the formation of the sediments.
Analysis of the Australian Banded Iron Formation showed that the rocks contain many scales of cyclic variation that roughly repeat at intervals of 10 and 85 cm.
Combining these thicknesses with the sedimentation rate, the scientists found that these cyclic variations occurred approximately every 11,000 and 100,000 years.
The analysis showed that the 11,000 year cycle observed in the rocks is likely associated with a climatic precession cycle that has a much shorter period than the current ~21,000 years.
Scientists then used this information to calculate the distance between the Earth and the Moon 2.46 billion years ago.
The researchers found that at that time the Moon was about 60,000 kilometers closer to the Earth, and the length of the day was approximately 17 hours.
Research in astronomy has provided models for the formation of the solar system and observations of current conditions.
This work represents one of the few methods for obtaining real data on the evolution of the solar system, which will be crucial for new models of the Earth-Moon system.
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