IMMENSITY OF THE HEAVENS.

New Zealand Graphic, Volume XIII, Issue VIII, 25 August 1894, Page 183

IMMENSITY OF THE HEAVENS.

If our sun were removed to the Pleiades it would hardly be visible in an opera glass with which nearly 100 stars can be seen in the cluster. Sixty or seventy Pleiades surpass our sun in brilliancy, Alcyone being 1,000 times more brilliant, Electra nearly 500 times, and Maia nearly 400 * Sirius itself takes a subordinate rank when compared with the five most brilliant members of a group the real magnificence of which we can thus in some degree apprehend.’ If we seek to know the dimensions, not of the individual stars, but of the cluster itself, we are met with many difficulties ; but, on the assumption that it is approximately spherical in shape, its diameter is so vast that light would take seven years to pass from one extreme to the other. If we think of the dimensions of our solar system by them selves, or in relation to terrestrial matter, they appear stupendously enormous. Neptune, the most distant known member, has an orbit over 5,000,000 000 miles across—a distance that a ray of light would travel in seven and a-half hours ; but the solar system is to the Pleiades but as a Lilliputian to a Brobdingnagian -is but as a microbe to a mountain, for a sphere the size of the solar system would, if it were spherical and its diameter that of the orbit of Neptune, be relatively so minute that it could be contained more than 400,000.000.000 times in a sphere the size of the Pleiades ; in other words, the limits of the Pleiades conld contain 150 solar systems as many times over as there are miles between Neptune and the sun. It must not be forgotten that, though there are 2,300 stars in the cluster, yet with such dimensions for the entire group vast distances must separate the stars from one another. In fact, 2.300 spheres, each with a diameter of 3.000.000,000 miles, could be contained in the limits assigned to the group, and, assuming equal distribution of the stars in the group, each would be at the centre of the sphere 3,000 000,000 miles across, and, therefore, a light journey of 187 days from its nearest neighbour.