A remarkable feature of our relation to the universe is that our solar system seems to be very near its centre. That we are near the central plane of the Milky Way is shown by the fact that the latter is nearly a great circle on the celestial sphere. It is true that the most exact determination yet made shows a slight displacement of our system, since the central line of the Milky Way is about one degree from that of the great circle which would pass near est to it. Another basis for the same conclu sion is that the stars seem about equally numer ous in the direction of the two opposite poles of the Milky Way. If there is any deviation from equality, it seems likely that the faint telescopic stars are fewer in number toward the south pole than toward the north pole of the Milky Way. This view is not yet proved, and cannot be until we have more exact counts of the stars of each order of magnitude in the two hemispheres. The question whether our system is situated with equal exactness in the centre of the great girdle does not admit of settle ment. All we can say is, that, up to the present time, there is no positive evidence on which to base a statement that we are any nearer one point of the girdle than another. It is indeed
true that, in the constellations Aquila and Sagittarius, which are visible in the south on autumn evenings, the Milky Way shows numer ous rifts and vacant spaces which are not shown on its opposite side. This might seem to indicate that we are nearer to it in this region. But further .researches are required before a definite conclusion can be reached.
It should be remarked that, even if. we are at present centrally situated, the position can not be permanently held. The motion of the solar system through space, by which we are carried forward on a journey of which we can see neither the beginning nor the end, at the rate of 10 or 12 miles a second, must eventually carry our posterity away from the centre of the universe, even if we are now situated near that point. But this motion will have to be con tinued hundreds of thousands, even millions, of years before the displacement would be ap preciable when compared with the dimensions of the universe.
StmoN Newcoms. Revised by Eatc Doourrt.E.