Ok I'll bite. During New Moon no one can see the moon. It is at this point the moon takes a little nap.
I'm not so sure. This was the person who thought a single hydrogen atom could be in the liquid state and could be encased in plastic in order to study it at leisure.
Out of curiosity - simply to see where such a strange idea, that would defy the known laws of physics, springs from... what source have you seen that suggests this?
Theoretically, a satellite (moon) orbiting a parent body (earth) might at some point in its orbit move in exactly the opposite direction (and at "reverse speed", so to speak) as the parent body's motion about a senior parental body (sun). Just thought I would point that out. So can the moon be momentarily motionless within the frame of reference of the solar system? That is a question which resides within the realm of sanity! Now, someone else explain why not . . .
It is theoretically possible, but that wasn't the question that was asked. Earth's moon is never stationary relative to the Sun, or relative to the Earth.
Maybe River is referring to ''Lunar standstill'' which is an apparent effect seen on the celestial sphere. Lunar Standstill. https://en.wikipedia.org/wiki/Lunar_standstill#Apparent_position_of_the_Moon_during_standstill