[snip]

Originally Posted by
Nereid
One thing to cross off, before starting to take a look at the Jerry ATM idea: to what extent does the density of an object depend upon its distance from the Sun?
No direct correlation. This is completely different from solar theory, but I am assuming the planets were captured 'brown dwarf' like objects, and that they did not condense from a dust cloud.
For example, if an object (an asteroid perhaps) has a highly eccentric orbit, does its density vary, according to distance from the Sun? Or is its density the same, no matter where in the solar system it may find itself?
Any body in a highly elliptical orbit should deviate more from Newtonian prediction than a body in a more circular orbit. If we put transmitter/receivers on a asteroid, as the asteroid approached the sun, the increase in velocity due to the increasing effect of solar gravity, should be measurable less than Newtonian predictions. (This loss of momentum is conserved in the general 'gravimetric' field of the sun.)
As the asteroid leaves close proximity with the sun, most, but not quote all, of energy is returned to the asteroid. There is more energy lost when a orbiting body is close to the sun in an eccentric orbit. This helps explain why dark comets like Tempel 1, with precious little thermal capacity, are as likely to outgas from the side of the comet not facing the sun, as the sol-facing side. It also explains how planets that were captured in very eccentric orbits become more circular.
Why don’t we see this with probes? We did: Pioneer 6 Doppler shows a marked diversion in velocity as it neared the sun, slowing more than expected. As the probe passed the limb of the sun, the velocity increased again. The Pioneer 6 anomaly was pointed out to me by a Ari Jokimaki after I describe this attribute of the solar system in an earlier thread. (This Doppler oddity is attributed to coronal magnetic effects.)
http://www.bautforum.com/showthread.php?t=13695
If this is correct, we should expect, to see just as much heavy metal in the outer solar system as in the inner solar system. There is one obvious exception: the Saturn system is loaded with water. Titan and Phoebe are much more dense than your run-of –the-mill Saturn moons and contain little water, relative to the rest of the Saturn moons. Phoebe appears to be a recent acquisition, I don’t know why there is so little water on Titan. The more distant planets and moons are at least as dense as those in the inner solar system.
For completeness, I guess I should also ask about volume and mass - to what extent are either of these dependent upon the object's distance from the Sun?
I don’t have an estimate for the sun.