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

Please recommend a textbook reference for the proposition that field strength of a fixed mass at a fixed distance from the center increases with density.

As a counterexample, I have a copy of Stephen Eales' Planets and Planetary Systems to hand. Eales quotes the high school equation for Newton's law of universal gravitation without qualification, which I read as force per unit mass (outside the object) is proportional to mass divided by the square of the distance from the centre of mass. (ISBN 9780470016930, Wiley-Blackwell 2009, p.106)

InfantGorilla (talk)07:30, 24 August 2010

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.

99.254.218.71 (talk)16:49, 25 August 2010

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.

InfantGorilla (talk)17:25, 25 August 2010