The Moon

Joel TomeAaron Fujioka

Pd. 3

The Moon

• A roughly spherical and rocky body which orbits the Earth at an average distance of 382,942 km

• Moon diameter = ¼ Earth diameter

• Moon mass = 1/80 Earth mass

Rotation and Orbit• Rotates on axis every 29.5 days• Axis tilted• Craters near south pole always in shadows• Sidereal month: complete orbit of Earth • Synodic month: one lunar day, relative to sun

Origin and Evolution

• Collision known as “Giant Impact” or the “Big Whack”

• Occurred 4.6 billion years ago between Earth and planet-sized object

• Resulted in a cloud of vaporized rock which came from Earth’s surface

Origin and Evolution cont.

• Vaporized rock went into Earth’s orbit• Cloud cooled and condensed into a ring of

small and solid bodies• Gathered together and formed the moon

Origin and Evolution cont.

• The quick joining together released lots of energy as heat

• Creating an “ocean” of magma• It slowly cooled and solidified

Origin and Evolution cont.

• As the crust formed, asteroids continually hit the moon

• One created the South Pole-Aitken Basin• One of the largest known impact craters in

solar system

Interior of the Moon• Crust- Average thickness is 43 miles • Mantle- Formed during period of global

melting, low density minerals floated to the outer layers and dense minerals sank deeper

• Core- Radius of 250 miles, consists mostly of iron and may contain large amounts of sulfur

Surface Features• Craters: result from meteoroids, asteroids, comets• Basins: craters 190 mi or more in diameter, rings

vary with size• Maria: dark areas on the surface of the moon

(16% of SA)

Surface Features cont.

• Wrinkle ridges: blister-like humps across Maria

• Rilies: snakelike depression across Maria• Volcanic features: dome/cone-shaped areas

The moon’s volcanic past

• Contained active volcanoes for billions of years

• Large dark areas filling the moon’s craters indicate the largest volcanic flows

• Almost exclusively on the near side

Works Cited• Angelo, Joseph A., Jr. "Moon." Science Online. Facts On File, Inc. Web. 21 Jan. 2011.

<http://www.fofweb.com/activelink2.asp?ItemID=WE40&SID=5&iPin=ESA1805&SingleRecord=True>.

• Elkins-Tanton, Linda T. "Moon." Science Online. Facts On File, Inc. Web. 18 Jan. 2011. <http://www.fofweb.com/activelink2.asp?ItemID=WE40&SID=5&iPin=SSEM0007&SingleRecord=True>.

• "Moon." Gale Encyclopedia of Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner. 4th ed. Detroit: Gale Group, 2008. Discovering Collection. Gale. Mid-Pacific Institute. 14 Jan. 2011 <http://find.galegroup.com/srcx/infomark.do?&contentSet=GSRC&type=retrieve&tabID=T001&prodId=DC&docId=EJ2644041517&source=gale&srcprod=DISC&userGroupName=mid&version=1.0>.

• Spudis, Paul D. "Moon." World Book Advanced. World Book, 2011. Web. 18 Jan. 2011.