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ultimately the moon will crash into the Earth

The moon is moving away from us because it is further than the distance of the geosynchronous orbit, ...

...but as the Earth's day slows down, the geosynchronous orbit grows, and it is growing faster than the moon is shifting, so eventually they will be the same. (when the length of the day will be equal to the length of the month). After this point, any loss of energy from the system will result in the moon moving CLOSER to the Earth, as it will be lower than a synchronous orbit.

Unfortunately, I don't think we gain much information about atomic scale physics from studying astronomic interactions...There is definitely a relationship between mass and probability of being very close (or in) the nucleus. If you replace an electron with a muon (also negatively charged, but more massive) the average distance falls significantly. I don't think this is an effect of gravity though, as it can be modeled perfectly (for hydrogen-like atoms) by wave functions generated without including gravitational terms. There probably is some extremely tiny contribution that gravity has at the subatomic scale, but I don't know how we would go about testing that...

#14 evan_au says:"... as the Moon moves farther from the Earth, it's rotational velocity decreases". [/size]Sorry, but that is erroneous. With a pull exactly towards Earth´s C.G., the whole pull would be centripetal, and it would keep the Moon following an exactly circular orbit. But mentioned misalignment of tidal bulge originates a relatively small tangential component of Earth´s pull. And according to Newtons´s 2nd Principle, a tangential acceleration occurs, tangential velocity increases, and so does its square divided by the radius at considered instant. And that is the centripetal acceleration necessary to have a circular movement at that increased speed ...But Earth has not increased its pull at that distance, and cannot produce the necessary centripetal force.The result is that Moon´s orbit cannot be kept exactly circular: it is a kind of very, very "closed" spiral.Eventually, Moon´s distance from Earth gets perceptibly bigger.

#17 Janus says:"... As the tangential acceleration affects the Moon, in climb away from the Earth, this involves an increase in gravitational potential energy. This increase is actually greater than the energy it gained from the tidal acceleration, and this is made up for by a loss of kinetic energy for the Moon; it decreases its orbital speed".I had not seen your post until now ... I have to ruminate it more quietly.It´s clear that Moon´s angular speed has to decrease, but I´m now not quite sure about tangential speed. In any case, I can´t actually understand your reasoning: how if Moon continuously suffers the tangential acceleration due to Earth tidal bulge tangential attraction, it climbs away from the Earth, and it gets "too high" potential energy increase, and then it has to decrease its kinetic energy and velocity, to compensate ...I´m realizing now that gravitational energy should actually decrease with the "climb away from the Earth", because it is mass times g and times distance. Distance increases, but g decreases inversely to the square of the distance, doesn´t it?

#20 JanusO.K.: potential energy is not an absolute value, but a magnitude always referred to an agreed zero level, and your examples put clear it is positive if we pass from a zero level distance to a higher distance ...But I´m seeing this concept is more tricky than what it appears.Gravitational potential energy is linked to a gravitational field, in our case consisting in all "g" values, Earth´s pull on the unit of mass at each point. Those pulls are forces always radial. in the direction of Earth´s C.G. It is clear that if e.g. we throw a stone vertically upwards in a vacuum (no friction), initial kinetic energy will change into potential energy until maximum hight, due to "g" negative acceleration. And the addition of both energies would keep constant. And similarly when falling back.But Moon in orbit around Earth has constantly zero "vertical" speed. Earth´s pull does not change any speed vertically, nor does the tangential component of the tidal bulge´s pull we are considering. If this one increases Moon´s tangential speed, we should not consider this increase has to be slowed back because Moon´s distance increases and potential energy increases too.They are stuff linked to vectors perpendicular to each other, which can operate independently ...

We should also keep in mind that after sufficient time of Moon-Earth distance increasing, Sun related tidal effects would get bigger than Moon´s ... If Sun not evolved as we know it will, a "fight" between Sun and Moon would happen ... Would Earth end synchronized to the Moon (as Moon is already), or to the Sun?