HOLES IN THE SKY.

Dunstan Times, Issue 2479, 3 May 1909, Page 8

HOLES IN THE SKY.

It has been known to astronomers for many year's that there are depths in the sky that no telescope can fathom. If this means that there are no stars in these places, there must exist straight starless paths through space, leading directly away from the earth, and these must either be of infinite length, or else there is some medium in space capable of absorbing light. This latter alternative astronomers have always been very reluctant to admit, for a light-absorbing medium would doubtless resist the motion of the heavenly bodies, and we have good evidence that such obstruction does not take place. The latest theory seems to be that these “holes in the sky” are only apparently empty; that they are really full of what may be called “dark nebula}.” Says a contributor to the Revue Sdentiiique“No one can observe the starry sky, through the telescope, on a clear night, without being struck by the existence of certain dark void spaces, which form, here and there, large black spots in the midst of the luminous star-dust, especially in the Milky Way. Various hypotheses have been advanced to explain these strange appearances. The simplest of all is that we have here celestial deserts, altogether without stars. Nevertheless we learn from the Bulletin of the French Astronomical Society that the eminent American astronomer E. E. Barnard, of the Yerkes Observatory, has advanced another hypothesis, which is very interesting not only because it is new, but because, in case it is verified by subsequent observation, it will sensibly modify our ideas of the structure of the universe. Some astronomers have supposed that these abysses are not only without stars, but that they are darker than the surrounding sky. Others attribute this appearance to the effect of contrast, which would cease if the nearer stars should disappear. Now, according to Mr Barnard, these abysses have objective existence, and are filled with nebulous matter. They are empty of stars, but not of substance, and reveal to us, in. certain regions of space, the existence of a dark nebulous substratum. Since the hypothesis of Laplace [the nebular hypothesis] has been opposed by that of Lockyer, that is, by, the meteoric hypothesis, according to which the nebula) are not necessarily destined to develop into suns, it seems probable that these sidereal formations of gaesous matter, like the stars themselves, are not eternal; that they are born and disappear, and that after their death they may remain obscure and invisible in the shades of space, except when their presence is revealed to us by the absorption that they exert on the light of more distant stars. On the other hand, the connection that exists between the nebulas and the celestial voids, the strange fact that the outer layers of a nebula seem, to melt into the darkness of the sky, as if this obscurity were something really tan-gible-all these peculiarities, even now so little known, will doubtless some day aid in revealing to us the real constitution of the universe.”-