Due to tidal action in the Moon-Earth system, the dissipation of tidal energy causes the Moon’s orbit to continue to decay, which means that the distance between the Moon and Earth will become more and more distant. than. Today, the average distance between the Earth and the Moon is about 384,400km. So, what was the distance between the Earth and the Moon in the age of the dinosaurs? Does the Moon look bigger now?
Due to the topography of the Earth, different regions of the Earth will see the Moon at different rates, so the Moon’s gravity will cause the Earth to have a tidal effect. As the Earth itself is still rotating, the Earth’s tidal elevation will be in the opposite direction of rotation, slowing the Earth’s rotation.
The moon revolves around the Earth itself, but is tidally locked to our planet.
The moon revolves around the Earth itself, but is tidally locked to our planet. Therefore, the orbital period of the Moon coincides with its rotation period, in addition, the angular momentum of the Moon – Earth system is always preserved, this phenomenon is the loss of energy of both planets. pure.
In addition to slowing Earth’s rotation, it also causes the Moon’s orbit to expand.
It can be seen that over the past 1 billion years, the decay rate of the Moon’s orbit has not changed much, and the change of the Earth-Moon distance over time is essentially linear. For the convenience of calculations, scientists think that the decay rate of the moon’s orbit in the past is similar to the present in the past billion years, that is, about 3.82 cm/year.
Dinosaurs first appeared about 240 million years ago. At that time, the average distance between the Earth and the Moon was about 375,200km, which is closer than today’s 9,200km.
In the time of the dinosaurs, the Moon was closer to the Earth than it is now.
It can be seen that this change in distance is not very large, the average apparent diameter of the moon 240 million years ago was 0.531 degrees, and now the average apparent diameter of the moon today is about 0.518 degrees.
Therefore, the area of the Moon as seen from Earth 240 million years ago was only 5% larger than it is today, this change in proportion would also not be detected by the naked eye.
According to calculations, when it was formed, the distance between the Moon and Earth was just over 20,000km.
While the moon is slowly moving away from Earth, the period of rotation around the axis of the third planet in the solar system is gradually increasing. The Earth currently rotates on its axis in about 24 hours, in the age of the dinosaurs 21 hours and only 4 hours in the early days of the Earth.
According to calculations, with the speed of the Moon’s distance from Earth in the past 10,000 years, the Moon has moved away from the Earth by 380m.
Thus, it will take about 5 billion years for the Moon to travel 200,000 km. Even so, then the Moon will still be in Earth’s orbit with a different cycle than now.
Another 5 billion years will also be the time when the Sun will enter the period of swelling of its crust and become a red giant so massive that it will crush Venus, Mercury and both the Earth and the Moon.
That’s a long time for a human life so we don’t need to worry about it.