These immense forces must be transmitted by the ether, and it is instructive to consider their amount.
Some Astronomical Forces which the
Ether has to Transmit.
Arithmetical Calculation of the Pull of the Earth on the Moon.
The mass of the earth is 6000 trillion (6 × 1021) tons. The mass of the moon is 1/80th that of the earth. Terrestrial gravity at the moon's distance (which is 60 earth radii) must be reduced in the ratio 1:60²; that is, it must be 1/3600th of what it is here.
Consequently the pull of the earth on the moon is
6 × 1021 / 80 × 3600 tons weight.
A pillar of steel which could transmit this force, provided it could sustain a tension of 40 tons to the square inch, would have a diameter of about 400 miles; as stated in the text, page 102.
If this force were to be transmitted by a forest of weightless pillars each a square foot in cross-section, with a tension of 30 tons to the square inch throughout, there would have to be 5 million million of them.
Arithmetical Calculation of the Pull of the Sun on the Earth.
The mass of the earth is 6 × 1021 tons. The intensity of solar gravity at the sun's surface is 25 times ordinary terrestrial gravity.