Lecture 5 -- Moon: Continued
Friday June 7
Earthrise: Apollo 8. Moon always faces the Earth, but the Earth will appear to rise as Apollo orbits it
Earthshine: Young moon, light bounces from moon to Earth, to moon, back to Earth
Lunar eclipse: Moon goes into Earth's shadow. Shadow is bigger than the moon, but much smaller than the angle the moon's motion can make with the ecliptic. They always happen during a full moon
Solar Eclipses: moon passes between Earth and sun.
Total Eclipse: Moon is just about the same size as sun in the sky (coincidence) You can see the corona, hot solar atmosphere
Prominence: block out the sun's surface, can see solar storms
Progression from partial to full
Maria -- dark regions, huge impacts, creating basins, followed by flooding with lava, highlands with many craters in the S. Craters--formed by impacts, saturated in highlands, no lava flooding. There are no maria on the far side, because the crust is thicker. Probably due to the presence of the Earth and tides. Moon was formed molten, and the lightest stuff floated to the top, just like on the Earth.
3/4 Moon: Terminator--end of light. Limb--edge of moon. Mountains--really just the edges of large, old basins. Galileo saw mountains on the moon and realized that it was another world. No plate tectonics on the moon, no volcanoes. Moon was small and cooled easily. Very thick lithosphere
Age of surface -- older surface has been collecting impacts longer. If we know the rate of impacts, we know how old the surface is. This can be calibrated by using Apollo radioactive dating of rocks. Maria are younger -- 3.5 By old, highlands are older, 4.5 By old
Impact ejecta--rocks and debris thrown out by larger impacts.
Rocks and Ice balls from space
One the size of an atomic bomb explodes in the air every year
One big enough to blow out your backyard every 100 years
One big enough to kill dinosaurs (or anything else) every 100 My
Major land altering events, traces gone due to erosion by water and wind
Earth impact: In arizona, 25,000 years ago, 2 km across
Basin: Mare Imbrium, rays from Tycho, smooth lava floor, crater Plato with lava filled floor
Folding of cooled lava sheets. Big craters have central peaks, too, and raised rims
Mountain range on Moon: Edge of Mare Imbrium, called the Apennines
Lunar exploration: First foot on the moon. The soil on the surface is called regolith. It's fine-grained like soil, but it is not soil. Soil is caused on the Earth by the breakdown of rocks by algae, and contains organic matter, bacteria. On the moon, it is caused by 4.5 By of bombarding by tiny dust particles, breaking up the surface. No air to stop them
Apollo 11 Landing Site on the edge of Mare Tranquillitatis, smooth area for easy landing
Aldrin's first step
Laser ranging reflector--used for distance to moon and continental drift measurements of the Earth--laser in Hawaii
Returning to the Command Module
Apollo 15 Landing Site--on the edge of the Apennines
They had a lunar rover -- 2 km range
Apollo 15 Landing site: 20 km scale bar
20 km scale bar--looking straight down, looks like river, it's called a rille--probably from lava
They landed near the edge of the rille--2 km scale bar
200 m scale bar. Many small craters
Show the traverse of Apollo 15 astronauts in their buggy
Apollo 17 astronauts in highlands, looking at a huge boulder, ejected from a huge distant crater
Rock, rough Taurus Littrow area of Apollo 17
VIDEO: FOR ALL MANKIND (Second half)
6/7/96
