Why is only one side of the moon visible from the earth at all times?
Only one side of the moon is visible from the earth at all times because the other side is illuminated by the sun, which doesn't face us.
Please correct me if I'm wrong, thanks :-)
You are wrong. Think about it.
If the "other side" (facing away from us)was always illuminated by the sun, we would never see a full moon.
We never see the other side because the moon rotates on its axis once a lunar month, always keeping the same side facing Earth. Asronomers say the rotation period is "locked" to the orbital period.
This not unusual in astronomy when the bodies are not perfect spheres.
Thank you so much drwls:-)
No, your understanding is not correct. The reason why only one side of the moon is visible from the earth at all times is actually due to a phenomenon called tidal locking. Tidal locking is the result of the gravitational forces between the Earth and the Moon and its effect on the Moon's rotation.
The moon takes approximately the same amount of time to complete one orbit around the Earth as it does to complete one rotation on its own axis. This means that the same side of the moon always faces the Earth. This is caused by the gravitational force of the Earth acting on the moon, causing a bulge on the near side of the moon. The Moon's rotation slows down due to this bulge, eventually resulting in the synchronized rotation we observe, with one side always facing the Earth.
So, it is not because the other side of the moon is illuminated by the sun and not facing us, but rather it is due to the gravitational interaction between the Earth and the Moon causing the moon to be tidally locked with the Earth.