When night comes, when you look up at the moon, do you think that the moon is not as big and round as you saw when you were young? This is because in addition to various weather and environmental factors, the moon we see is gradually moving away from us.
In fact, on the earth hundreds of thousands of years ago, the creatures who lived on the earth at that time saw a larger and rounder moon than we can see now, not only because the air quality hundreds of thousands of years ago was better than now, but because the moon was running away from home because of its own orbit around the earth.
So why does the moon turn farther and farther away? To figure this out, we first need to understand the relationship between the moon and the Earth.
The Moon is Earth's only natural satellite, the Diameter of the Moon is much smaller than Earth, only 2476 kilometers, and the Earth is about 50 times the size of the Moon. And we can see the moon on a clear night from birth, because the moon is doing an orbit around the earth.
Of course, there are not a few planets with moons in the solar system, and the moon can only rank fifth among these moons. But what's interesting is that the distance between the Earth and the Moon puts the other eight planets in the solar system perfectly.
And friends who like to observe will find that the moon is always facing the earth in one side, because the distance between the earth and the moon is just so that the moon is tidally locked by the gravitational pull of the earth, so that the moon can only face the earth in one side. At the same time, the moon itself is not luminous, and the moonlight we see during the full moon is actually because the sun shines on the surface of the moon, and the moonlight is the sunlight reflected by the moon on the earth.
But such a beautiful moon is likely to be gone in millions of years.
The Moon is moving away from us at a rate of 3.8 centimeters per year, although this 3.8 centimeters is obviously insignificant to these large objects. But we need to know that the earth is now nearly 5 billion years old, even if it is 100 million years, the moon will be 3800 kilometers away from the earth. As early as the beginning of the Earth-Moon system, the Moon seen on Earth was much larger than it is now, and it is likely that half of the nightfall of the early Earth night was occupied by the Moon.
Then one wonders why the moon is gradually moving away from the Earth. Is it because the moon is seeking other planets?
In fact, in order to understand this problem, we must first know how the Earth-Moon system was formed, although there is no very authoritative statement, but there are some more reliable hypotheses.
As early as the beginning of the birth of the earth, the rotation speed of the earth was very fast. Thus part of the separation from the earth itself, since then this rock mass has been absorbing cosmic dust gradually formed our current moon; the second theory is that the moon was originally a moving planet in the solar system, but because of its relatively light mass, it was captured by the earth by chance and became a natural satellite of the earth.
The reason why the moon will leave us is because of the gravitational pull between the earth and the moon. The moon's orbit around the earth is not just a regular circular motion, but according to the earth's rotation around the sun and do elliptical movement, when the earth runs to the perihelion, the moon will be farther away from us, when the earth runs to the aphelion point, the earth will be closer to us. The gravitational pull will also change due to the distance from the sun.
What if, one day in the future, the Moon ceases to orbit the Earth?
The Moon could leave Earth in millions of years, and what happens there could be some big disaster. Friends who have carefully observed the lunar surface may find that the lunar surface is really broken, and various craters stand impressively on the lunar surface.
This is a great contribution that the moon has done for us, that is, to help us block most of the extraterrestrial visitors, and in the early days of the earth's birth, it blocked a large number of meteorites, which provided valuable conditions for the earth to conceive life.
At the same time, because of the traction of the moon, the oceans on the earth have the ebb and flow, the marine life can be enriched, and the fishermen who rely on the sea can return home with a full load when they go to sea.
At the beginning of the early Earth' birth, the Earth's rotation rate was very fast, averaging less than 10 hours a day, until the later Moon joined the Earth's gravitational range, which slowed down the Earth's rotation speed, so that it has the current 24 hours a day.
In millions of years, the moon will move faster and faster from the earth until it is completely invisible, when the tidal reaction on the earth will not appear, the land on the surface may be partially submerged by seawater, and the rotation rate of the earth will return to the early 10 hours a day, when the pace of people's daily life will become very fast, and the pressure of life will increase a lot.
I believe that at that time, human beings should have some changes according to these environments, such as the 996 work system may no longer exist?