BELLRINGERBELLRINGER

Explain in complete sentences what is

the Sun-Earth-Moon system.

Previous homework, due todayPrevious homework, due today

DESCRIBE IN DETAILS WHAT IS GEOGRAPHIC

LOCATION AND COORDINATES OF A CERTAIN PLACE

NEW HOMEWORK, due NEW HOMEWORK, due tomorrowtomorrow

DESCRIBE MAJOR PROPERTIS OF

THE SUN-EARTH-MOON

SYSTEM

The Sun-Earth-Moon The Sun-Earth-Moon SystemSystemRotationRotation

Coriolis EffectCoriolis EffectTidesTides

RevolutionRevolutionSeasonsSeasons

MoonMoonLunar EclipseLunar EclipseSolar EclipseSolar Eclipse

The photographs show what the moon looks like from Earth. The drawings show what the moon would look like from space.

PHASES

OF

THE

MOON

Lunar EclipseLunar Eclipse

Earth’s shadow falls on the moonEarth’s shadow falls on the mooncan can onlyonly occur at Full Moon occur at Full Moon

UMBRAUMBRA – darkest part of the shadow, a – darkest part of the shadow, a region where the Earth blocks region where the Earth blocks allall direct direct sunlight from reaching the Moon. sunlight from reaching the Moon.

PENUMBRAPENUMBRA – cone of shadow cast by – cone of shadow cast by deflected light, a zone where the Earth deflected light, a zone where the Earth blocks part but not all of the Sun's rays blocks part but not all of the Sun's rays from reaching the Moon from reaching the Moon

Lunar EclipseLunar Eclipse

There is a full moon once a month – why not There is a full moon once a month – why not a lunar eclipse?a lunar eclipse?All 3 bodies must be in perfect alignmentAll 3 bodies must be in perfect alignmentMust be nighttime when alignment occurs, only Must be nighttime when alignment occurs, only

half the planet is experiencing night at a given half the planet is experiencing night at a given timetime

During Full Moon phase, the moon usually passes During Full Moon phase, the moon usually passes above or below Earth's shadows and misses them above or below Earth's shadows and misses them entirely. No eclipse takes place. entirely. No eclipse takes place.

Two to four times each year, the Moon passes Two to four times each year, the Moon passes through some portion of the Earth's penumbral or through some portion of the Earth's penumbral or umbral shadows resulting in an eclipseumbral shadows resulting in an eclipse

MOONMOON

The moon's orbital plane does not The moon's orbital plane does not "lie flat" along the ecliptic, but "lie flat" along the ecliptic, but forms an angle of about 5º - affects forms an angle of about 5º - affects chances of experiencing an eclipse. chances of experiencing an eclipse.

(note: the distances in this diagram are not to scale)(note: the distances in this diagram are not to scale)

Earth’s orbit around the sun

MOONMOONPath of moon through

Earth’s shadow during total

eclipse in 2000.

Note: the moon

does not pass

directly through the

center of the

UMBRA

LUNAR ECLIPSELUNAR ECLIPSE

Partial Lunar EclipsePartial Lunar Eclipse A A portionportion of the Moon passes through Earth's of the Moon passes through Earth's

umbral shadow. umbral shadow. These events are easy to see, even with the These events are easy to see, even with the

unaided eye. unaided eye. Total Lunar EclipseTotal Lunar Eclipse

The The entireentire Moon passes through Earth's umbral Moon passes through Earth's umbral shadow. shadow.

These events are quite striking for the vibrant These events are quite striking for the vibrant range of colors the Moon can take on during range of colors the Moon can take on during the total phase (i.e. - totality). the total phase (i.e. - totality).

LUNAR ECLIPSELUNAR ECLIPSE

When an eclipse of the Moon takes When an eclipse of the Moon takes place, everyone on the night side of place, everyone on the night side of Earth can see it. Earth can see it. About 35% of all eclipses are of the About 35% of all eclipses are of the

penumbral type which are very difficult to penumbral type which are very difficult to detect, even with a telescope. detect, even with a telescope.

30% are partial eclipses which are easy to 30% are partial eclipses which are easy to see with the unaided eye. see with the unaided eye.

35% or so are total eclipses, and these 35% or so are total eclipses, and these are quite extraordinary events to behold.are quite extraordinary events to behold.

LUNAR ECLIPSELUNAR ECLIPSE

Indirect sunlight still manages to reach and illuminate it.

However, this sunlight must first pass deep through the Earth's atmosphere which filters out most of the blue colored light.

The remaining light is a deep red or orange in color and is much dimmer than pure white sunlight.

Earth's atmosphere also bends or refracts some of this light so that a small fraction of it can reach and illuminate the Moon.

If the Earth had no atmosphere, then the Moon would be completely black during a total eclipse. Instead, the Moon can take on a range of colors.

The filtering and refracting effect of Earth's atmosphere makes the total phase of a lunar eclipse interesting.

The exact appearance depends on how much dust and clouds are present in Earth's atmosphere.

Major volcanic eruptions tend to make total eclipses very dark, since these events dump large amounts of ash into Earth's atmosphere.

During the total lunar eclipse of December 1992, dust from Mount Pinatubo rendered the Moon nearly invisible.

LUNAR ECLIPSELUNAR ECLIPSE

SOLAR ECLIPSESOLAR ECLIPSE Moon moves directly between Earth and Moon moves directly between Earth and

the sunthe sunUMBRAUMBRA – Dark inner shadow; total – Dark inner shadow; total

eclipses are seen from within this eclipses are seen from within this shadow. The track of the Moon's shadow shadow. The track of the Moon's shadow across Earth's surface is called the across Earth's surface is called the Path Path of Totalityof Totality. It is typically 10,000 miles . It is typically 10,000 miles long but only 100 miles or so wide. long but only 100 miles or so wide.

PENUMBRAPENUMBRA – Faint outer shadow; – Faint outer shadow; partial eclipses are seen from within this partial eclipses are seen from within this shadowshadow. .

SOLAR ECLIPSESOLAR ECLIPSE

There is a NEW moon once a month – why There is a NEW moon once a month – why not a solar eclipse?not a solar eclipse?All 3 bodies must be in perfect alignmentAll 3 bodies must be in perfect alignmentDuring New Moon phase, the moon’s shadow During New Moon phase, the moon’s shadow

usually passes above or below our planet and usually passes above or below our planet and misses Earth entirely. No eclipse takes place. misses Earth entirely. No eclipse takes place.

At least twice each year, the 3 bodies line up At least twice each year, the 3 bodies line up so that some part of the moon’s shadow falls so that some part of the moon’s shadow falls on Earth’s surfaceon Earth’s surface

An eclipse of the Sun is seen from that regionAn eclipse of the Sun is seen from that region

2000 Jul 31: Partial Solar Eclipsehttp://sunearth.gsfc.nasa.gov/eclipse/OH/OH2000.html

SOLAR ECLIPSESOLAR ECLIPSE

QUESTIONSQUESTIONS Describe the two types of planetary Describe the two types of planetary

motion.motion. Why does the Earth have tides?Why does the Earth have tides? What is the relationship between tides and What is the relationship between tides and

waves?waves? What are the characteristics of a wave?What are the characteristics of a wave? What causes the Coriolis Effect? What is What causes the Coriolis Effect? What is

the Coriolis Effect? the Coriolis Effect? Why does the Earth have seasons?Why does the Earth have seasons? What is the difference between a solstice What is the difference between a solstice

and an equinox?and an equinox?

QUESTIONSQUESTIONS

What is the difference between a What is the difference between a solar eclipse and a lunar eclipse? solar eclipse and a lunar eclipse?

When can you see a total solar When can you see a total solar eclipse? A total lunar eclipse?eclipse? A total lunar eclipse?