TIME AND SPACE

Evening Post, Volume CXIII, Issue 112, 14 May 1927, Page 20

TIME AND SPACE

DIVISION BY LIGHT YEARS,

Some idea of the immensities of time and space may be gathered incidentally from a most fascinating picture of the system formed by the great nebulae, painted by Dr. Hubble, of Mount Wilkoii Observatory, California, in an article in a recent issue of the "Astrophysical Journal." Dr. Hubble has recently been using the giant lOOm telescope to examine the distribution in space of the great nebulae. As far back as about 1800 Sir William Herschel thought that each of these great nebulae might be comparable in size and in content of matter to the whole syntem of about l,000,000 : 00l» stars bounded by. the "Milky Way," of which our sun is a member. Dr. Hubble now finds that this is actualy tho case. Tho faint nebulae appoar faint merely because of their great distance. The faintest visible in the Mount Wilson tolescopo are ao remote that their light takes 140,000,000. years, to reach us. Within this distance some two million nebulate must lie. Dr. Hubble finds that these are fairly uniformly spaced at an average distance of about 1,800,----000 light years apart. Some idea of tho. immensity of these figures may bo gathered from the fact that hitherto the farthest objects known from our planet have been at a distance mainly about 1,000,000 light years. From his conclusions it would appear that the nebulae are evenly spaced rather like the stars, only on a much more colossal scale. - In " Nature," Dr. Jeans, secretary of the Royal Society, in a letter describing Dr. Hubble's conclusions, makes the same suggestion as to the origin of the nebulae as Newton made in 1692 to explain the origin of the Btars. As far back as that year, the famous philosoph.er held the theory that if you,had an enormously big mass of gas spread out in space it would 1 condense into distinct masses of gas, which ho thought ■might explain the origin of tKe stars. Dr. Jeans in 1901 calculated how far

apart the stars would be had they been formed in this way. And on the supposition that the origin of the nebulae is similar to Newtown's explanation of the origin of the stars, calculations made by Dr. Jeans at what. distance apart nebulae ought to form work out at very nearly the actual average distanco observed by Dr. Hubble, mainly about 1,000,000 light yoars. Dr. Joans writes in his letter to "Nature": To construct a model take 20 tons of walnuts and :space thorn at about 25 yards apart, thus filling a sphero of about a mile radius. This sphere is the rango of vision of the lOOm telescope; each walnut is a nebulae containing matter enough for the creation of perhaps a thousand million suns like ourseach atom in each walnut is a solar system with a diameter equal to that of the earth's orbit. The definition of nebulao in the Oxford dictionary is an indistinct cloud-like cluster of distant stars. '■'• ■'•■■'