Fragments of Science -

Front Cover
Read Books, 2007 - Science - 472 pages
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1902 Excerpt: ...earth. r' = radius of moon, or other body. P = moon's horizontal parallax = earth's angular semidiameter as seen from the moon. f = moon's angular semidiameter. Now = P (in circular measure), r'-r = r (in circular measure);.'. r: r':: P: P', or (radius of earth): (radios of moon):: (moon's parallax): (moon's semidiameter). Examples. 1. Taking the moon's horizontal parallax as 57', and its angular diameter as 32', find its radius in miles, assuming the earth's radius to be 4000 miles. Here moon's semidiameter = 16';.-. 4000::: 57': 16';.-. r = 400 16 = 1123 miles. 2. The sun's horizontal parallax being 8"8, and his angular diameter 32V find his diameter in miles. ' Am. 872,727 miles. 3. The synodic period of Venus being 584 days, find the angle gained in each minute of time on the earth round the sun as centre. Am. l"-54 per minute. 4. Find the angular velocity with which Venus crosses the sun's disc, assuming the distances of Venus and the earth from the sun are as 7 to 10, as given by Bode's Law. Since (fig. 50) S V: VA:: 7: 3. But Srhas a relative angular velocity round the sun of l"-54 per minute (see Example 3); therefore, the relative angular velocity of A V round A is greater than this in the ratio of 7: 3, which gives an approximate result of 3"-6 per minute, the true rate being about 4" per minute. Annual ParaUax. 95. We have already seen that no displacement of the observer due to a change of position on the earth's surface could apparently affect the direction of a fixed star. However, as the earth in its annual motion describes an orbit of about 92 million miles radius round the sun, the different positions in space from which an observer views the fixed stars from time to time throughout the year must be separated ...

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About the author (2007)

John Tyndall resides in London, Ontario. His publications include Thirteen Poems: From the Bruce Peninsula (1974), Howlcat Fugues. This book was also chosen by the Library Journal as one of the ten best small-press poetry books of 1976. His first book published by Black Moss was titled Free Rein (2001). His poems have also appeared on thespoken-word CD entitled Souwesto Words: 25 Poets In Southwestern Ontario, Canada (1999) and in the anthologies That Sign of Perfection, Losers First, I Want to Be the Poet of Your Kneecaps, Henry's Creature, and Following the Plough.. Tyndall's poetry has been praised in the University of Toronto Quarterly for its "strange iridescent language," and by the Library Journal for its "surrealistic melding of poetry and art.

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