The Ether of Space

ely, it was thought to be, it is useful to remember that not only has it to be the vehicle of light and the medi

certain smallness can be more than counterbalanced even by the pressure which their mutual radiation exerts-almost infinitesimal though that is;-so that as a matter of fact, s

een the two forces will obtain for two wooden spheres in space if each is about a foot in diameter; according to Professor Poynting's data (Philosophical Transactions, Vol. 202, p. 541). For smaller or hotter bodies, radiation repulsion overpowers mutual gravitation; a

t molecular distance, attract each other

(10-8)2 = 10-44/10-1

no perceptible a

ust be entirely negligible. And yet it is to the aggregate attraction of myriads of such bodies that the resultant force of attraction is

gravitation overpowers all other forces; and all electric an

mitted by the ether, and it is ins

omical Forc

as to T

tion of the Pull of

that of the earth. Terrestrial gravity at the moon's distance (which is 60 earth radi

pull of the ear

80 × 3600 t

ould sustain a tension of 40 tons to the square inch, would have

each a square foot in cross-section, with a tension of 30 tons to the s

tion of the Pull of

intensity of solar gravity at the sun's surf

y 200 solar radii, solar gravity will b

exerted by the s

21 / (200)2

equal to the weight of 37 × 1017 ord

square inch of cross-section. The cross-section of a bar of such steel, co

quare

× 1012 sq

llion million round rods or pi

the text (page 26) is

the Earth

h, which has just been calculated; but it furnishes another mode of arriving at the result, and may b

n is 316,000 times

f the sun is, say,

or pull of the su

00)2 × 6 × 10

al to the ordinary commercial weight of

l Force acting

the centrifugal force of the earth; namely, its mass, multiplied by the square

(2π

the lengt

instructive, owing to the manipu

(4π2 × 92 × 106 mi

multiplied by an acceler

133300 × (24)2 mil

133300 × 576 × (3600)2

00 × 576 × 12·96 × 32

/

mass, produces in it an acceleration equal to the 1/1640th part of

021 tons

× 1021 to

ry weight of 37 × 1

se due to the approximate character of the data selected, which are t

of the projected earth's hemisphere or area of equatorial plane,-the force transmitted by each would have to be 2700 tons; and

Planet on

ny planet on the earth, even Neptune, distant though it is, is still a gigantic force.

Star on

ay a star, for example, which is 20 times the mass of the

s pull by the squared ratio of 24 years to 8 min

rth and the whole solar system, at its present speed through space, is only able to curve t

to hold togethe

Double

Such forces must be transmitted with perfect ease, for there are plenty of cases where the force of gravitation is vastly greater than that. In the case of double stars, fo

some days double and alternate days single. Clearly it must consist of a pair of luminous objects revolving in a plane approximately containing the line of vision; the revolution being completed every four days. For the lines will then be optically displaced by the motion, during part of the or

timated, enabling us to calculate the speed

age 403, 1889, says that the velocity amounts to about 150 miles

these

d uniformit

s per se

od 4

tive pull between them. For the star must consist of two equal bodies, revolving

ily give the radius of the circul

ifugal and cen

= γ m2

T2 of the earth, we find the mass of each body must be about 3

with the nearer portions as they revolve. If they are of something like solar density their diameter will be comparable to half a million miles, and the natural periods

n. Let us continue the calcul

, revolving with angular velocity 2π ÷ 4

/ 16 miles per day per day; which comes out 32 / 2·2 ft. per

een the two components of

× 18 × 1

to the

tons on

on times as great as is the pul

niform and incompressible character of etherial constitution. Even the idea of "massiveness" as applied to the ether involves an element of uncertainty, or of figurativeness; because until we know more about ether's peculiar nature (if it is peculiar), we have to deal with it in accordance with material analogies, and must specify its massiveness as that which would have to be possessed by it if it fulfilled its functions and yet were anything like ordinary matt