PROBLEMS OF MARS.

New Zealand Herald, Volume XLVI, Issue 14144, 20 August 1909, Page 7

PROBLEMS OF MARS.

mgmf, WILL THEY BE SOLVED NEXT \ MONTH? 8®?. PROPOSED SIGNALLING. Cji-; Towards the latter part of next month— It 1 ' -'.Ho bo more precise as to time, on SepQ , tember 24, at eight p.m.—a most import- ■, ant astronomical phenomenon will take Mi-f', place, the "opposition" of the planet | i Mars (writes Mr. Raymond, officer in \T charge of the Sydney Observatory, in the ('V ' Sydney Daily Telegraph). Seen in the eastern sky at the present time a few hours after sunset, it has a V • most striking appearance— of a ball > ? of fire —and I think it has been mistaken by many as "some peculiar lights in the • heavens," and of which reports have lately appeared in the press. At the time of writing (August 13), Mars is approximately 42,000,000 of miles , from us, but getting closer some o 200,000 miles each day, so that, on September 18 next, when the planet will make ■ its closest approach to our earth, it will be about -55,000,000 of miles away. Some

33 might ask, Should not the planet appear

an its brightest on that date? Not so, for >;'it must be understood that Mars shows /phases similar to our moon, and, although on September 18 it is at its nearest to us, • ! - the earth is so placed in its orbit at that " time that the whole of its illuminated' |f| surface is not seen by us, and the appear- >>; ance of the planet in good telescopes will - be somewhat similar to the moon a day or two before being full. Not until six £, days after the nearest approach will the

position of the earth be such that we will

see the full phase of Mars. The sun, earth, and Mars will then be in* line. These phases of Mars were discovered by : the great Italian astronomer, Galileo, (Ai-3y in the 17th century, and they go to r '■' '-■ prove that Mars does not shine by its own light, but by the reflected light of the ran. ....".' The last opposition occurred on July 26, 1907, and, although Mare and the earth rere in very advantageous paths of their

respective orbits for the phenomenon, more

so than many of the previous oppositions, still the coming opposition will* find the two bodies even better placed. ■ It may be as well to explain here why Mars and the earth are closer at one opposition than another. This is due to the --■ pronounced eccentricity of the orbit of the former. Whereas the orbit of the earth

. is an ellipse with very little departure from the circle, the major and minor radii , differing only" some three millions of miles / ' from one another; the difference of the two

radii in the case of Mars is over 27 millions Si- of miles, the minor radius 128 millions and the major 155 millions of miles. Of all

the planets in the solar system, Mercury

has the most eccentric orbit, -with Mara

next la order; th© least in order of eccen-l'-j: tricity is Venus, then. Neptune, earth, etc

It -will thus be understood that two bodies • 'revolving around another body, but whose • distance from that body is not constant, !will at some periods of their revolutions be

;!;;; imuch closer than at others. That is as it happens in the case of Mars "and our earth. '~ *"' 'The most, favourable . opposition has a dis-, *tanoe of 35 millions of miles., the least favourably placed 61 millions. Hence at the opposition when the planet is at the ilast-mentioned distance from the earth it •',;;/' appears to be only half the size when at the *S former, the ratio being '4.7. — ■ ■; .. fjCj*""* "' IS MARS INHABITED? ; ' ''• it is during these oppositions that astronomers expect to. find important informa-

tion about our neighbour, whether it is m

" IB condition similar to our earthif peopled "by intelligent beings, and if they have customs and habits similar to our own. Great preparations are being made by come American astronomers to signal Mars

during this opposition, and all |he world's , greatest telescopes will be turned towards the planet to observe if the Martians (if there be such) have received those signals. V But although discovery may not go as far "as that in our day still something great may b» expected. The so-called canals

will be photographedmany times, and so have this important matter settled beyond all doubt. Other natural features of Mars . will also receive their proper . portion of attention, and we may, arrive at some de-

finite conclusion as to the distribution of

; land and water on the planet. At the . present time it is presumed that very "little water exists on Mars, practically the ; only supply being derived from, the melti ing of the snow at the poles. The peculiar colour of this planet is probably due to the ruddy nature of the soil. ABOUT THE CANALS. x Mars canals were first discovered by the • Italian astronomer, Schiaparelli, in the year 1877, and were called canali, or channels, by him, and he made further obser- • vations on several subsequent occasions un- ■ , til failing sight put a stop to his great •' work in the year 1890. To Italy is thus due the great discoveries of the phases ; and canals of Mars. Of recent astronomers, Professors Pickering and Lowell, the former at Harvard College Observatory, U.S.A., and the latter • : -at the observatory, Flagstaff, Arizona, •U.S.A., have given much of their time to Unravelling the mysteries of Mars. Professor Pickering was the discoverer of the many spots connected with the canal " system, which may be great works of water conservation, and Professor Lowell, from hie observatory, had photographs obtained • by Mr. Lamplands, showing the canal sys- . tem during the opposition in 1905. That •.astronomer practically makes a speciality . of Mars study, and is, perhaps, the world's > greatest authority on the planet. • Mara revolves on its axis almost in the - .same time as the earth, taking only 40 minutes more for the revolution, but its year consists of 687 of our days, or 669 of its own. It travels around its orbit at a speed • glower than the earth, the rate being 15 miles against 18 miles per second. Other • -•. resemblances between the two planets are '. the tilt, of their equators to the plane of ( " their orbits, so that similar seasons prevail / on both. They are, of course, longer on >'■..■ Mars, as the Martian year is nearly twice *: ; . as long as the terrestrial year, and owing to the eccentricity of Mars orbit previously described the seasons are not of equal : Jj :; : length. As summer approaches on the planet the snow at the poles thaw and the snow caps greatly decrease in size, expand*i''.v.;.'.ing again on the approach of the winter seaeon, jt also possesses an atmosphere similar ' to the earth, for occasionally the markings ■on its surface are observed by patches of cloud. .

Our amateur astronomers should not let this opposition pase without attention, providing favourable weather prevails;, and we Way expect something good from zealous •■ ■ worker?. To those who have .sketching ability they should make drawings of the planet as they see it in their telescopes, if possible colour drawings. . During previqus ; oppositions, Mr. G. H. Hirst, a. member of the New South Wales -branch of the British Astronomical Association, made some very :'.■'■'. perfect, sketches of Mars. On _: September 24 next others should follow, his example, ■nd it would be very interesting to them to Compare their work with the photographs ,*hich will ultimately appear in the scien--:;.'!i; tific journals. To those who have a. penchant for observing a very complete list of fevr|sUrs appears in the Nautical Almanac for 1&09, : and they could 'profitably devote their t'»me to this observing in order to determine ' ,m parallax of the planet,.