that is, just over three-quarters of the planet’s speed in its orbit.

If we suppose the particles to be equally distributed in space, we shall have more with a given major axis in proportion to that axis, and our integral will become

⌠¹
(2a₁ - 1)½ a₁½ da
½

⸻⸻⸻⸻⸻

⌠¹
a₁ da
½
1
= 8/3[(4a₁-1)/8 (2a₁² - a₁)½ - (1/16√2 ) log[(2a₁² - a₁)½ + √2 · a₁ - 1/2√2]]
½
= 0.792 of the planet’s orbital speed.

The speed v, then, at which a satellite must be moving round the planet to have the same velocity as the average particle within the planet’s orbit, is

V - v₁ = v.

This velocity is, for the several planets:—

Distribution of
Particles as their
Major Axes
Distribution of
Particles Equal
in Space
Miles a secondMiles a second
Jupiter2.01.6
Saturn1.51.2
Uranus1.00.9
Neptune  0.80.7