The Arizona sentinel., 1888-07-28

" to solve in ascertaining the distances of the stars, is one of the greatest diff ..fculty, and not until within compara- lively recent time have any satisfac- tory results been attained to reward the careful observations Of centuries. Of all the thousands of stars that have been studied, astronomers know the distances of about twenty, and even these are known only approximately, being the supposed distances within which they can not be, but beyond which they must be, though the exact limits can not at present be determined, owing to the immense intervals which separate them from our earth.
 The nearest star is so remote that it's light requires three and a half years to reach us, while the light of the Polar Star is forty-fve years arriving to us from that distant and prominent orb; so that if the light of this star was suddenly extinguished to day, nearly half century would have to elapse be- fore we should be aware of the fact, and miss the familiar orb from its place in the nothern heavens.
 The mathematical principles involved in determining the distance of star are essentially the same as those en- plOyed by surveyor when he wishes to measure the width of stream which he can not cross, only with the astron- omer the problem is rendered much more difficult from the fact that he is unable to secure a base-line of sufficient length to meet his requirements; even the diameter of the earth's orbit is not great enough to use in measuring the distances of stars, with very few ex- captions.
 To learn the distance of the stars it is first necessary to determine what is known as the stars parallax, or its angle of direction when viewed from the two opposite points in the earth's orbit, and this is what renders the problem so extremely difficult, for nearly every star that has been ex- amined for the purpose of learning its distance has failed to show any paral- lax whatever, and in few instances where a parallax has been recognized the angle is found, to be exceedingly small. No star in the heavens has a parallax equal to one second of arc, but all thus far determined are below even this small angle.
 The star which gives the greatest parallax of any and is believed to be the nearest to our earth, is Alpha Cen tauri, first magnitude star in the southern heavens, and never visible in our latitude. But even this stars par allax is only 93-100 of a second, which corresponds to a distance of 221, ,000 times the suns distance from our earth, or over 20,000,OOO, 100000 of miles! And this, remember, is the nearest star at present known to astronomers.
 The earth's orbit, seen from this star, would appear the same as circle six-tenths of an inch in diameter, viewed at the distance of one mile; and the radius of that orbit (the dis tance which separates the sun from our earth) would be entirely hidden by a fine thread, or spiders web, one-twen- ty-ffth of an inch in diameter, held $50 feet from the eye! In other words, line lo4, 100000 miles long, looked at broadslde, would shrink into a mere point; and if our sun were removed to that distance, it would shine with a light only equal to that of the North star, while its parallax would be but | the one-hundredth of second,
 There are some stars so remote that their light, though travelling with a velocity of 186,000 miles per second. can not reach us in less than 10000 | years. To traverse the Milky Way, of which our own solar system forms a part, light requires 15,000 years; and to reach us from some of the distant nebulse. which appear like faint clouds, and are hardly visible through the largest telescope, it must travel for 300 times that period, or nearly 5,0OO,0O0 years.
 To ordinary vision, all the stars ap- pear at rest in the heavens, nor can the astronoRer himself recognize any signs of motion, except by patient and long continued observation, extending, tn some instances, over period of