Moon movements and Phases

Movements of the Moon Rises in the east, sets in the west and travels across the southern sky Rises 52 minutes later each day because the earth is rotating to catch up with the moon’s position due to revolution Moonrise to moonset is approximately 12 hours Rising and setting time vary with seasons

Moon’s axis is tilted 6° from vertical Moon’s orbit is tilted about 5° off the earth’s orbit Earth and moon are rarely in a straight line

Rotation is counter clockwise and 27 1/3 days with respect to the background of stars Revolution is counterclockwise and 27 1/3 days with respect to the background of stars

Synchronous rotation Speed of moon’s rotation is 6 mph much slower than its revolution speed Only one side of the moon faces the earth

Earth E Moon’s orbit Perigee Apogee

Phases of the Moon We view the moon by seeing sunlight reflected from the moon Amount of sunlight the moon reflects towards the earth changes daily because the moon is revolving around the earth and changing its angle

Phases of the Moon Revolution of the moon from being between the earth and sun and back to the same position is longer than the time required to match the star background 29.5 days

New moon Rising time –sunrise Highest pt—noon Setting time—sunset Between earth and sun No moon is visible

Waxing Crescent Rising time –between sunrise and noon Highest pt—between noon and sunset Setting time— between sunset and midnight Small sliver on right hand side visible In western sky just after sunset

Waxing Quarter Rising time –noon Highest pt—sunset Setting time— midnight One half of moon visible on right side Due south at sunset May be visible in afternoon Sometimes called First Quarter

Waxing Gibbous Rising time –between noon and sunset Highest pt—between sunset and midnight Setting time— between midnight and sunrise More than half of moon visible on right side Easily visible in afternoon

Full Moon Rising time – sunset Highest pt—midnight Setting time— sunrise Full disk of moon visible Brightest moon

Waning Gibbous Rising time – between sunset and midnight Highest pt– between midnight and sunrise Setting time— between sunrise and noon More than half visible on left side Visible in morning sky

Waning Quarter Rising time – midnight Highest pt—sunrise Setting time— noon Half of moon visible on left side May be visible in the morning Sometimes called Third quarter

Waning Crescent Rising time – between midnite and sunrise Highest pt—between sunrise and noon Setting time— between noon and sunset Tiny sliver of moon on left side only Earthshine visible Just before sunrise in eastern sky

E SUN

Earthshine Light bouncing off the earth onto the moon and back to earth Usually clearest at crescent phases. Drowned out at other faces by sunlight reflecting back

Eclipses of the Sun and Moon

What is an eclipse? Passing of an object into the shadow of another object Sun-Earth-Moon must be in a perfectly straight line in order for this to occur

Ground E W

Solar Eclipses

Moon moves between Earth and Sun New moon phase The moon’s two shadows strike the part of the Earth Total eclipses rare – only once every 360 years from one location!

Parts of the Shadow Umbra—dark central portion that causes total eclipse Penumbra—lighter part that causes a partial eclipse

Total Solar Eclipse Lasts no longer than 8 minutes because moon and earth are revolving and will not be in line for long Distance the moon is from the sun will effect the duration of the eclipse - shorter when far away; longer when closer

Partial Solar Eclipse Last longer because the penumbra shadow is larger More common for any one place.

Annular Solar Eclipse Occurs when moon is at or near apogee Only center part of sun is covered

Bailey's Beads

Diamond Ring

Solar Corona

Next Solar Eclipse in the World March 19, 2007 Partial Solar Far East Far East September 11, 2007 Partial Solar South America and Antarctica South America and Antarctica February 7, 2008Annular Antarctica and Southern Pacific Antarctica and Southern Pacific August 1, 2008 Greenland and North Central Russia Greenland and North Central Russia

Next Solar Eclipse in Virginia If you live in the extreme southeast corner of Virginia, the next total solar eclipse you will be able to see as total will happen on May 11, You'll have to wait until Sep. 14, 2099 for the next total solar eclipse that will be total over central Virginia.

Next solar eclipses in Northern Virgina April 12, 2154 Annular April 13, 2200 Total Other times and places: as/SEatlas.html as/SEatlas.html

Lunar Eclipse

Moon moves into Earth’s shadow – this shadow darkens the Moon Full moon phase About 2-3 per year Last up to 4 hours

Partial Eclipse Total Eclipse

Lunar Eclipse Sequence

Why doesn’t moon disappear Earth’s atmosphere refracts red light into the shadow and turns the moon a red color

Next Lunar Eclipse visible here March Total Lunar Eclipse Europe and Africa Europe and Africa August Total Lunar Eclipse Mid Pacific Ocean Mid Pacific Ocean Feb 21, 2008 Total Lunar Eclipse Central and Eastern United States, South America, Eastern Mexico and Central America Central and Eastern United States, South America, Eastern Mexico and Central America

Lunar Geology

The Moon’s Surface No atmosphere No liquid water Extreme temperatures Daytime = 130  C (265°F) Nighttime = -190  C (- 310  F) 1/6 Earth’s gravity What would you weigh on the moon?

Lunar Features: Regolith Dusty surface of the moon Compares to our soil but without life or water Compares to our soil but without life or water Heavily cratered and pulverized rock

Lunar Features - Maria Darkest parts of lunar landscape Filled by lava after crash of huge meteorites on lunar surface 3-4 billion years ago Mostly basalt rock

Maria Terrain

Rilles Collapsed lava tubes or fault cliffs Usually appear as straight or wavy lines Most often seen in maria

Lunar Features - Highlands Mountains up to 7500 m (25,000 ft) tall Lighter in color Most common rocks are breccia and anorthosite

Apollo 16

Lunar Features - Craters Up to 2500 km (1,553 miles) across Most formed by meteorite impact on the Moon Some formed by volcanic action inside the Moon

Rays Light streaks of material blown out by crater impact Not always visible

Copernicus’ Rays

Far Side of the Moon First seen by Luna 3 Russian space probe in 1959 Surface features different from near side More craters More craters Very few maria Very few maria Thicker crust Thicker crust

Exploring the Moon 1950s to 1960s - probes Neil Armstrong First man on the Moon – July 20, 1969 Six Apollo missions ( ) 382 kg (842 lbs) rocks 382 kg (842 lbs) rocks 12 Americans have walked on the moon

How the Moon was Formed Most scientists believe that the moon was formed from the ejected material after the Earth collided with a Mars-sized object. This ejected material coalesced into the moon that went into orbit around the Earth. This catastrophic collision occurred about 60 million years after Earth itself formed (about 4.3 billion years ago). This is determined by the radioisotope dating of moon rocks