Comments from feedback form - "So it may be shrinking. Its ma..."

InfantGorilla, thank you for your reference. I will seek out a counter reference and get back to you asap. We must keep in mind that Newtonian equations break down when it comes to explaining extreme phenomena, such as black holes. Within an Einsteinian curved, spacetime framework, gravity is no longer a force and can act instantaneously at a distance. This discovery has had severe consequences for modern cosmology. I'll get back to you, even if it is to prove myself wrong.

Thanks. I don't know Einstein's equations for gravity. An effect of increased density, even if too small to measure for normal matter, will be interesting.

Meanwhile, I suspect the complexities of classical dynamics dominate relativity in the Earth-Moon system: I have read that the slow retreat of the Moon is caused by tidal forces.