Next Next Previous Previous

Sun, Moon and Earth

19 The Moons gravitational pull M lifts the oceans on the side of the Earth facing the Moon. On the opposite side, centrifugal force causes a sim i lar effect C, because the centre of mass and so of rotation of the EarthMoon sys tem does not lie at the centre of the Earth. The Sun also pulls at the oceans S, and ac cord ing to the phase of the Moon adds or subtracts to and from the height of the tide. Spring tides occur near full and new Moons upper, the lesser neap tides at the quar termoons lower. The month ly ratio be tween the heights of spring and neap tides is 83. 19 18 the lunar day tides of lunar time Anyone who lives by the sea witnesses the inexorable silent power of the Moon, whose invisible claws draw the tides up and down the beach twice a day. Tides are not just limited to the oceans the Earths atmosphere above our heads and even its crust beneath our feet rise and fall to this lunar rhythm. The highest spring tides occur two or three days following a new or full moon. The lowrange neap tides occur two days after a waxing or waning quarter moon. The lunar day is the time between consecutive moonrises, the Moon rising an average of 52 minutes later each day. There are exactly two tides each lunar day, each taking an average 12 hours and 26 minutes. Tides are thus synchronised to the lunar day and therefore to the Moons position in the sky. High tides will always occur at the same two positions of the Moon in the sky at any given location, these being opposite each other one position is always beneath the horizon. Knowing where the Moon is in the sky, you can also know the state of the tide locally. There are 28 lunar days and therefore 57 tides 3 x 19 in each lunation cycle. In isolation tanks, human bodily rhythms eventually transfer from the the solar to the lunar day. The Earth and Moon form a huge dumbbell in space, with their centre of rotation located about 1000 miles beneath the Earths surface shown as a chequered circle opposite. 1 2
From Other Books..
Currently Browsing:
Buy and download E-Book PDF
Buy Softback from Amazon
Buy Hardback from Amazon
Keywords on this page
Show fewer keywords
Show more keywords
See Also:
Log In
Authors List
Comments
Series Titles
Covers
Special Offers
Home
Powered by Ergonet BookBrowser Engine
x