A mysterious "hump" at the Moon's equator indicates that the Earth was devoid of oceans of liquid water for the first 400-500 million years of its existence, which imposes serious restrictions on the time of origin of life, according to an article published in the journal Geophysical Research Letters.
“The Earth's hydrosphere, if it existed at that time, was completely frozen, as a result of which the tidal forces practically did not“slow down”the Moon. The reason for this, we assume, may be that the Sun was not as bright then as it is today,”says Shijie Zhong from the University of Colorado in Boulder (USA).
For the past 30 years, it has been generally accepted that the Moon was formed as a result of the collision of Theia, a protoplanetary body, with the "embryo" of the Earth. The collision led to the release of the matter of Theia and the proto-Earth into space, from this matter the Moon was formed, which explains its amazing geological and chemical similarity with our planet.
In the early epochs of its existence, the Moon looked completely different from what it does today - its interior and surface were completely melted, it had an exotic superdense atmosphere of silicon and metal vapors, and was located 10 times closer to the Earth's surface than today.
In the next several million years, according to scientists today, the Moon was rapidly moving away from the Earth as a result of the action of tidal forces, occupying approximately the orbit in which it is today. Subsequently, when the Moon always began to look at the Earth with only one side, this process slowed down sharply and now it "escapes" from our planet at a speed of about 2-4 centimeters per year.
Zhong and his colleagues uncovered one unusual detail of this process, drawing attention to the most mysterious feature of the moon - its unusual "hump" located at the equator of the Earth's companion. This structure was discovered by the famous French astronomer Pierre Laplace two centuries ago, when he noticed that the Moon was "flattened" about 17-20 times more than the speed of its rotation around its axis indicates.
Scientists today believe that the existence of this structure indicates that in the distant past, the moon rotated much faster than today. American planetary scientists tried to understand how quickly the Moon "slowed down" by studying how this "hump" works and trying to reproduce its birth using a computer model of the solar system.
These observations unexpectedly showed that the generally accepted theories about the rapid deceleration of the Moon in the early years of its existence were erroneous - the rotation speed of the Earth's satellite remained high for at least the first 400 million years of its existence. Otherwise, the Moon would always remain a "liquid" planet or have a completely different shape and size than it is today.
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Such a scenario, as Zhong explains, is possible only if the Earth was not covered at that time by an ocean of water comparable in size to the planet's current hydrosphere. this means that there was no liquid water on the young Earth - it was either absent on it in principle and was brought in after the formation of the Moon's "hump", or it was completely frozen.
Such conclusions put serious restrictions on the time of the appearance of life on Earth and make scientists doubt the recent statements by geologists that the first living organisms could have appeared on our planet as early as 4 billion years ago.
