ASTRONOMY.

Hawera & Normanby Star, Volume XLII, Issue XLII, 14 October 1922, Page 12

ASTRONOMY.

■ ♦ — LECTURE BY MR, WARD.

Although inclement . weather conditions prevailed last evening a large number of people attended a lecture on astronomy given at the Grand Theatre by Mr. J. T. Ward, hon. director of the Wanganui Observatory. Mr. Ward has a very extensive knowledge of his great subject,. and his address could not 'fail to impress his listeners and show up the insignificance of our tiny world as compared with the rest 'of the universe. The lecturer was introduced by Mr. P. ODea, who said that there was proJbably not a man in New Zealand who knew so much about astronomy as Mr. Ward. At any rate, Mr. Ward was the only man in New Zealand who could make all the parts of a telescope. In his opening remarks, Mr. Ward said that h© was going to deal with formations in the universe that were rather further off than many of the subjects usually chosen from the field of astronomy. First of all, however, he would deal briefly with the sun and the matter of eclipses before going so far into the reaches of the Universe. He would also refer to the work being done at several of. the large observatories in an endeavour to arrive at the dimensions of the Universe. The first man to make any valuable pronouncement on the structure of the. Universe was Secehi, who was convinced that the colours of the stars denoted the extent of heat. Then came Zollner, whose view was that yellow and red stars were> simply white stars in the process of cooling. Vogle set out to show that the condition of a star was mirrored in its spectrum. He took the same view that the white star was the beginning and the yellow and red star was. the condition that followed on. Norman Lockyer's views denoted the beginning, of the new idea that stars begin a.s great, diffused, comparatively cool bodies, and as they condense they radiate heat and become hotter, or, as the Americans say, "stars leak heat." The xcor© heat they part with the hotter they get, and eventually thny pass through all the stages to a dull red to shades of lighter red, to yellow, to white, and on to bluish white, when the star is considered to* be at its hottest. The process is then reversed and the star comes back gradually to to dull red star, and passes to extinction. The beginning "of. the star is an enormous body in which the substance is very loosely compacted, the density increasing as the star passes from one stage to another until it passes out. Its density is increasing all* the time as-long as its substance obeys the laws of gases. A young star is therefore generally a body of very great volume, and an old star is a. body of small volume, but very great density. The spectrum of each star is found to follow a sequence^ which is as 'orderly as .that of the musical scale. The evolution or the stellar bodies can be determined by the spectroscope tc move in a. direction which indicates the advance of temperature, a s nd the. different elements which are found in their spectra are revealed in accordance with this orderly sequence. So that in the bluish white star is found a preponderance of the lighter gases such as helium and hydrogen. Coming down the scale the lighter elements become weaker and fade out, and the heavier elements put in an appearance, till, when you get to the bottom of the scale the lighter elements have all gone and nothing but the heavier remain. The differentorders from the hottest to the coolest are denoted by the letters 0, 8., A, F, O, X, M, N, and these again are broken up into sub-groups, and the greater catalogue of Harvard University is based on these lines. Mr. Ward then proceeded with his lecture, using a. magic iantern for demonstration purposes. He dealt first with the sun and then with the nebulae and the great star clusters. At the conclusion of the address Mr. C A. Strack proposed V hearty vote of thanks to Mr. Ward. Mr. Strack said that Mr. Ward had given his audience a very real idea of the immensity of space. Mr. ODea read an apology for absence from Mr. Dixon, and the vote of thanks to Mr. Ward was carried with acclamation.