1. Chapter 9 The Moon

2. What causes eclipses of the Sun and the Moon? How can we predict eclipses? Predicting eclipses – The moon must be near a node to cause an eclipse, therefore the node must point toward the sun….eclipse season last for one month and happens every 5.7 months…the most you can have in a year is 7 – Every 18 years 11.33 days the same eclipse will happen…but is shift.33 the distance on the earth surface...which means 54 years 1 month for it to happen at the same location – Page 192 figure 9.16

3. How do tides affect the earth and moon Tides and the earth’s rotation – Tides cause the earth’s crust to rise and fall 20cm – This is gravitational friction between the moon and earth, the friction is slowing the rotation – The days on earth are getting longer by about 0.0015 seconds per century – 384 days 270 million, 407 days 440 million, day length has gone from 21.5 hours 440 mill to 22.8 hours 270 mill to 24 hours now – Evidence suggest that this was rapid at first – The tidal affects on the moon where so great, that the moon rotation was slowed

4. How do tides affect the earth and moon Tides and the Moon’s orbit – page 193 – How does friction affect the tides? – What affect does the tidal bulge have on the moon? – How has it changed the moon’s orbit in the past and present? – What about future eclipses? – What is a possible future of the earth moon system?

5. Points of reference First pretelescope observations done by Jan Van Eyck 1400’s and Leonardo da Vinci 1500’s Galileo in 1609 made the first real observations of the moon and began to name the features Giovanni Riccioli in the mid 1600’s started the custom of naming craters after notable scolars and the mountain ranges named after earth mountains

6. Points of reference Exploration of the moon began the 1950’s with robot flybys, several robots were crashed into the moon in the 1960’s and the ranger series used television cameras to take pictures of the moon’s surface 64 – 65 1966 both US and USSR landed several robots on the surface 1969 the US puts men on the moon Map mission in 1990’s and planned man missions in 2018?

7. How did the moon form Lunar Samples – 197 – Chemical composition: Aluminum, calcium, chromium, titanium, and uranium are in higher concentrations on the moon (form from high temp gases) – Water, sodium, chlorine, zinc and lead which easily vaporize are in low concentrations – These are some of the first clues as to the moon’s formation

8. How did the moon form Ages of lunar samples – 197 – 4.5 billion years old, thought to be formed shortly after lunar formation – Terrae rocks tend to be the oldest, Maria rocks tend to be less then 4 billion and at least 3.2 billion…no rock formation after this time Ages and Cratering – 198 -199 – What is crater density and what does rock age have to do with it? – How does this help us tell a history of the lunar surface? – How does this crater density compare with other satilities and planets?

9. How did the moon form The Moon’s Atmosphere – 199 – Before lunar mission the atmosphere was thought to be thin at best and most long running experiments have confirmed this fact – The atmosphere is mostly Helium, neon, argon, and hydrogen… it would fit into a 1 meter cube – The Apollo mission seriously contaminated the atmosphere of the moon….most of the gases turned to solids or liquids which allowed the experiments to be successful – Offers no insulation of the surface…temps from 260 degrees F to 36 degrees or less at night

10. How did the moon form Gain and loss of Gases – 200 – Come up with three questions and the information to answer them to share with the class The Moon’s interior – Mass of the moon has been determined by orbital period and distance of satellites in orbit – The mass of the moon is 1/81 of that of Earth, this means it is 81 times the distance from the center of the earth or 4700 km which places the center of the orbital plane 1700 km beneth the earth’s surface.

11. How did the moon form The density of the Moon – The moon is 3300 kg/m cubed, the Earth is 5500 kg/m cubed – Density of an object is determined by the materials in it and the amount of compression the undergo – The moons density is about that of the earth’s surface rock – The core appears to be partially molten rock between 440 and 700 km across or 3% of the moons mass, compared to the earths core which is 55% of the earth diameter and 33% of the mass

12. How did the moon form Lunar Seismology and internal structure – Moonquakes never over 2.0, speed of the waves indicate that the crust is 65 to 100 km thick with a lithosphere of 1000 km…it is thicker on the far side. – This may explain why there is a lack of Maria on the far side. The moon is still being hit by large objects – This may help explain why the moon is still warm (1/3 that of the earth), along with the large amount of radioactivity in the materials

13. How did the moon form The origin of the Moon – Fission, the moon was thrown off the earths surface because of a rapid rotation early in the planets evolution – If it happened after the iron sunk to the center this would explain the lack of iron on the moon – Problems, one the orbit should be at the equator.. two,how did we get the 4 hour rotation – Binary Accretion, Both objects formed from the same materials at the same time, problems does not explain the lack of iron – Capture theory, it formed somewhere else in the solar system, problems how did it overcome the energy problems and chemical composition of the moon

14. How did the moon form The giant impact theory – An object about the size of Mars collided with the earth, vaporing the object and part of the earth surface and mantle. – The material then jetted into space, some into interplanetary space, some fell to earth and some orbited the earth … highly volatile gases and materials would have escaped into space at this time – The earths core had already formed and only surface materials would have been ejected, the difference in make would be accounted for with other object.

15. Quiz CH 9 part 2 1.Explain how the Moon’s orbit has changed from the past to the present and possible future outcomes? 2.What is the Fission Theory? 3.What is the Binary Accretion Theory? 4.What is the Capture Theory? 5.What is the Giant Impact Theory and why is it currently the favored?