Sun Earth Moon Eclipses and Tides

8/8/2019 Sun Earth Moon Eclipses and Tides

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Sun, Earth, and Moon

Lunar Phases

Eclipses Tides

Celestial Motion


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Phases of the Moon

The appearance or shape of the Moon gradually

changes through the course of a month. Thiscycle - the cycle of lunar phases, may be

explained if we state the following:

1. The Moon is spherical in shape.2. The Moon is not self-luminous, but rather

reflects the light of the distant Sun.

3. The Moon circles the Earth once per month.


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Moon at Perigee and Apogee

Distance: 359,861

km

Distance: 405,948 km


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Eclipses

Celestial bodies are always eclipsing or

moving in front of each other.

Eclipses occur at predictable intervals.

Other names include: Transits and

Occultations.

Solar Eclipses can be total, partial, or

annular


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Moon's shadow on Earth taken by

French cosmonaut Jean-Pierre

Haigner aboard the Mir


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"Here lie the bodies of Ho and Hi,

Whose fate, though sad, is risible;

Being slain because they could not spyTh' eclipse which was invisible."

Author unknown: Said to refer to the Chinese

eclipse of 2136 BC or 2159 BC.

"On the day of the new moon, in the month of

Hiyar, the Sun was put to shame, and went

down in the daytime, with Mars in

attendance."

One of the earliest written records of an eclipse of the

Sun, on 3 May 1375 BC, found in the city of Ugarit in

Mesopotamia.(Reprinted, from Chasing the Shadow,

copyright 1994 by Joel K Harris and Richard L Talcott,

by permission of Kalmbach Publishing Co.

"If the Sun at its rising is like a crescent and

wears a crown like the Moon: the king wll

capture his enemy's land; evil will leave the

land, and (the land) will experience good . . . "

Refers to a solar eclipse of 27 May 669 BC.

Rasil the older, Babylonian scribe to the king.

Quoted in Historical Eclipses and Earth's Rotation, by F

Richard Stephenson, Cambridge University Press, 1997,

page 125.

"Nothing can be surprising any more or impossible or

miraculous, now that Zeus, father of the Olympians has

made night out of noonday, hiding the bright sunlight,

and . . . fear has come upon mankind. After this, men can

believe anything, expect anything. Don't any of you be

surprised in future if land beasts change places with

dolphins and go to live in their salty pastures, and get to

like the sounding waves of the sea more than the land,

while the dolphins prefer the mountains."

May refer to a total solar eclipse of 6 April 648 BC.

Archilochus, Greek poet (c680-640 BC)

Quoted in Historical Eclipses and Earth's Rotation, by F

Richard Stephenson, Cambridge University Press, 1997,

page 338. Partly quoted inEncyclopaedia Britannica CD

98.

ECLIPSE QUOTES


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1882 Transit

(USNO)


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Application to Exo Planet Studies

HD 209458 (mv = +7.7) in Pegasus


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When the moon is new or full, the

gravitational forces of the sun and

moon are pulling at the same side

of the earth. (See the diagram

below.) This occurrence creates

the extra large "spring" tides.

When the moon is at first andthird quarter, the gravitational

forces of the sun and moon are

pulling at 90 degrees from each

other. (see the diagram below.)

This occurrence yeilds little net

tides called neap tides.


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More Fun Tidal Tales.

Every few years people that measure such things (chronologists?) need to add a leapsecond to the year. The Earth's rotation is decelerating at a rate of about 0.002

seconds per day per century.

The Earth will eventually stop slowing down when its rotation is equal to the

moons orbital period !!!

The Proxigean Tide occurs when the Moon is at its closest point in its orbit to the

Earth and in its New orFull Moon phase. At this time, its tidal effect on the Earth is

maximum. The times when this will happen often coincide with major coastal

flooding events. Between 1997 and 2020 there will be 102 times when this will

happen.

The moon shows the same face to the Earth because it was deformed by Earths

gravity when it was still molten. Earth uses this memory to grab the moon and

slow its spin rate down.

WHY ?


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Resources

Paper Plate Astronomy http://analyzer.depaul.edu/paperplate/

Solar Events http://solarevents.org

Eclipses http://sunearth.gsfc.nasa.gov/eclipse/eclipse.html

Earth Moon Viewer http://www.fourmilab.ch/earthview/vplanet.html

Lunar Posn Calculator http://www.fourmilab.ch/earthview/pacalc.html

Lunar Phases, etc. http://www.lkwdpl.org/schools/elempath/heavenlymotion/

Sun Earth Moon Eclipses and Tides

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