SCIENCE JOTTINGS.

Digger (Invercargill RSA), Issue 21, 6 August 1920, Page 14

SCIENCE JOTTINGS.

Tlie distance from the earth to the sun is 93,000,000 miles. If we started out in a flying machine and travelled at the rate of 127,400 miles per day, without 'stopping for a whiskey and soda, it would take us two years to arrive there, The sun is over a million times greater than our earth, and 324,000 times heavier, Each of us carry an average weight of some 16 tons upon our shoulders. Perhaps some one will ask how it is that we are not crushed by this weight, bufc to which, never-the-less we appear insensible. It is because the aerial fluid enclosed within our bodies exerts a pressure equal and opposite to the external atmospheric pressure, and these pressures counteract each other. The earth's diameter at the eqnator is 7,926 miles. From one pole to the other, it is a little less, owing to the flattening of the polar caps. j.ne difference is about 27 miles. The circumference of the earth is 24,900 miles. It is surrounded by an aerial envelope, the atmospher.e, the height of which is generally believed to be about 186 miles.

There ar,e about 7,000 stars visible . to the naked ,eye. The sixth magnitude is the limit of visibility to the hnman eye. There are 19 stars of ihe first magnitude, 59 of the second, 182 of the third, 530 of the fourth, 1,600 of the fiffch, and 4,800 of the sixth magnitude. Seven thousand stars for the whole heavens makes only 3,500 for half the sky. And we can only see oue celestial heinisphere at a time. Celestial space is unlimited, and we must not suppose that these 7,000 stars which fascinate our eyes and enrich our heavens, and without which our nights would be black, dark, and empty, comprise the whole of creation. They only represent the vestibule of the temple. With the aid of the most powerful telescopes of the day, reinforced by celestial photography, can bring a stream of more than 120 millions of stars into the scope of our vision. Some time ago a photographic map was being prepared, and is possibly now coc - pleted. It comprises the first fourieen magnitudes, and will give the precise position of some 400 million stars.

Examination of star motions reveals the fact that our sun is hurrying with all his system (the earth included) towards the constellation of Hercules. We are ehanging our position every moment. By the time typists in governmjent offices have morning tea and discussed the merita of paint and powder, the earth is 43,000 miles farther away than we are at prasent. Thia is the distance travelled in one hoor The sun and the earth will never agaiu traverse the space they have just left, and which they have deserted for ever. Who has not noticed the Milky Way ? The pale belt that traverses the entire firraament. It is indeed a swarm of stars, each is individually too small to excite r «r retina, but as a whole, curiously enough, they are clearly visible. Eight million stars were counted there with the guage3 of Sir William Herschel.