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same time have very large diameters, it. will be evident that the near approach 
of another massive body would be sufficient to cause great disturbance. 
The attraction of the foreign body would cause the star to elongate, the 
gravitational attraction at the ends of the longer axis would be decreased 
and the highly compressed gases of the interior would cause great eruptions 
toward the disturbing body and away from it. Even with the slight dis- 
turbances to which our sun is subjected we have these vutbursts of materiaf 
from the interior, by which material is thrown out at times, to distances of 
a hundred thousand miles. 
If another star were to come within a few hundred thousand miles of 
our sun this effect would be produced on a scale many times greater. While 
the star was a considerable distance away these ejections of matter would 
be less violent. increasing in violence as the distance decreased, and, what 
is just as much to the poimt, they would be in a slightly different direction 
as time went on. The first masses ejected would be drawn out of a straight 
line and would eventually fall back toward the sun, some of them striking 
the surface and some of the 1 so far drawn to one side as to miss the surface 
as they came back, in which case they would continue to revolve in elliptical 
orbits about the sun. Those masses, thrown off a little later, would travel 
farther and in slightly different directions, and would be diverted still more 
and move in longer orbits. After a maximum disturbance was reached the 
same process would go on with decreasing violence as the disturbing body 
retreated into space. It has been shown that the masses thrown off which 
did not go back to form part of the sun again, might under these conditions 
form themselves into two spiral arms, the whole, of course, being in one 
plane, as the motion of the two stars would be in a plane. That material 
which did fall back into the sun would give to the part where it fell 
a certain velocity of rotation, and we find in the sun a higher rate of rotation 
for the equator than for any other part. The direction of motion of the 
matter composing the arms of the spiral is not along the arms but across 
them, each particle moving in an ellipse around the central mass. If 
masses of different sizes were ejected, the large ones would tend to annex 
the smaller ones in the immediate neighborhood, and the process before 
described would result in a system of planets and satellites much as we have 
in the solar system. 
We have this process still going on in a small way. The Earth attracts 
to itself several million small particles every day and occasionally there is a 
