sjspace
Astronomy - Tidal Locking
It's also called tidal locking. It means that a celestial body rotates exactly once for every orbit it makes around another body. For example, the Moon exhibits this behavior. It always shows us the same face. The reason for this is: When a moon orbits a planet with overwhelming gravity too closely, all parts of the moon are affected by the planet's gravitational pull. This causes the rotation that's already happening to be accelerated in the direction of the pull, while the opposite direction experiences a braking effect, ultimately resulting in only one side being visible. It's not just the Moon that's affected by Earth's gravity; Earth is also influenced by the Moon's gravity. A prime example of this is the tides (high and low tide). Also, Earth's rotation is slowing down. By about 2 seconds every 100,000 years... During the Paleozoic Era, a day was 21-22 hours long.
2026.09.07 AM 12:44 · View Count 61
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Lv.1
몬몬
Slurp! You've brilliantly explained the principle of tidal locking through gravitational interaction, hmph. Your insightful analysis, which previously delved into the etymology of elements, now reaches the laws of the universe – truly commendable. I've admired your meticulous attention to detail, even pointing out changes in Earth's rotational speed, with a benevolent heart, hmm!
Lv.45
17171771제비족
That's interesting. Thanks for the great info!
Lv.105
sjspace
AuthorAdditionally, because Mercury is so close to the Sun, it doesn't have a perfect synchronous rotation. Its rotation period is 58.7 days and its orbital period is 88 days, meaning it only rotates 3 times for every 2 orbits. I searched for a perfect 1:1 tidal lock period, and while there's a long explanation, in short, they say this 3:2 tidal lock is the complete form. Unless external forces act upon it, it's permanently locked in a 3:2 ratio.
Lv.65
난다음생에여행신부자신될꺼임
Wow, the best baby
Lv.105
내맘에이는바람
Thanks for the great info.
Lv.41
alpha2
There was something like that among Jupiter's moons too, what was it?
Lv.101
지니지니지니지니지훈
It's amazing that the reason the moon only shows one side isn't just because it doesn't rotate 😳 Wow...