My understanding is that one side is facing the sun and the other is facing away all the time, does that mean there is no planetary orbit?
Or is the orbit the planet some how matching how the planet rotates in proportion to its orbit around its star?
(I don’t know if that’s even how it works)
In: Physics
A planet is totally locked when it’s rotation about its own axis (a day) is the same length as it’s rotation around it’s sun (a year).
It’s the second one. Our moon for example rotated around its own axle in the same it take the moon to orbit around the earth. That’s why we always see the same side of the moon.
If the moon would not rotate around it’s own axle, you would see different parts. And after a complete orbit around the earth, you would see the same part of the moon again.
Normally the smaller object (the satellite) is the one that locks on the bigger object. But when the objects have roughly the same mass, they lock on to each other. A good example is Pluto with its moon Charon.
I believe this is caused by the main object’s (the thing something is getting tidally locked to) gravity slowly slowing down the rotation of the smaller object. This happened with Earth and the Moon, and the Moon is now doing it to Earth (although very, very slowly)
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