Cycles of the Moon - Chapter 3

As the Moon journeys from New to Full, the proportion of its illuminated side visible from Earth is (increasing/decreasing). This is known as (waxing/waning).

increasing waxing

why aren't solar eclipses separated by one saros cycle visible from the same location on Earth?

it would take a couple lifetimes to return to that same EXACT location. It may line up the EXACT same but it will be positioned in a different part of the world

Assume a crescent phase of the moon is observed in the early evening in the western sky. During the next few days the moon will be rising (earlier, later) and the visible, illuminated portion of the moon will become progressively (larger, smaller).

later larger

Chromosphere

layer of bright gas just above photosphere

The Full Moon is highest in the sky to an earthbound observer at (noon, sunset, midnight, sunrise).

midnight

solar eclipse

moon blocks some or all of sun's light from hitting Earth

Total eclipse (lunar or solar)

moon has a faint, red glow, reflecting sunlight scattered in Earth's atmosphere

What does it mean when astronomers state that the moon is tidally locked

moon is rotating with the same period around its axis as it its orbiting Earth

Partial Eclipse (lunar or solar)

moon partially enters the umbra

Penumbral eclipse

moon passes through penumbra and never reaches the umbra

If you looked back at Earth from the moon, what phase would Earth have when the moon was full? New? First quarter? waxing crescent?

moon: full, new, first, waxing earth: new, full, third, waning

The New Moon is highest in the sky to an earthbound observer at (noon, sunset, midnight, sunrise).

noon

At approximately what times will the third quarter moon rise and set?

Rise: Midnight Set: Noon

At approximately what times will the first quarter moon rise and set?

Rise: Noon Set: Midnight

Can only occur if the moon passes a node near New Moon

Solar Eclipse

How would eclipses be different if the moon's orbit were not tipped with respect to the plane of Earth's orbit?

Solar eclipses every New Moon Lunar eclipses every Full Moon

A Full Moon first becomes visible to an earthbound observer positioned at (noon, sunset, midnight, sunrise), and he or she must look (eastward, westward) to see the rising moon.

Sunset, eastward

The length of time it takes to complete the cycle of lunar phases is called what?

Synodic

Sidereal Period

Time it takes for Moon to complete one full orbit of Earth

about how many days must elapse between first and third quarter moon?

14-15 days

Saros cycle

18 years 11 days and 8 hours later, the exact eclipse will happen again, only in a different part of the world

node

2 locations where the moon's orbit crosses the ecliptic

how long does a sidereal take?

27.3 days

How long does a synodic take?

29.5 days

Eclipse Season

32 days for Solar 22 days for Lunar

Path of totality

the path that the moon's shadow traces Earth during a total solar eclipse

Synodic Period

time it takes for Moon to complete one cycle of phases (New Moon - New Moon)

If a solar eclipse occurs on October 3: (a) why can't there be a lunar eclipse on October 13? (b) why can't there be a solar eclipse on December 28?

(a) takes a minimum of 14 days, from october 3-13 is not 14 days (b) too early for the sun to match up. (no longer near a node)

Lunar Eclipse

Earth comes between Sun & New Moon (moon passes through Earth's full shadow)

When is the only time a Lunar Eclipse can occur?

Full Moon

Identify the phases of the moon if at sunset the moon is (a) near the eastern horizon, (b) high in southern sky, (c) in the southern sky, (d) in the southwestern horizon

Full Moon First Quarter Waxing Gibbous Waxing Crescent

Can only occur if the moon passes a node near Full Moon

Lunar Eclipse

If on March 1 the Full Moon is near Spica, when will the moon next be (a) Full, (b) near Spica?

March 30 March 28 (27.5 days later)

When is the only time a solar eclipse can occur?

New Moon

Identify the phases of the moon if on March 21 the moon is located at the point on the ecliptic called (a) Vernal Equinox, (b) Autumnal Equinox, (c) Summer Solstice, (d) Winter Solstice

New Moon Full Moon First Quarter Third Quarter

Can a Full Moon be observed from Earth by an observer positioned at noon? Explain your reasoning.

No, Full Moon rises 6am, sets 6pm

If a planet has a moon, must that moon go through the same phases that Earth's moon displays? explain.

No, because the moon may be positioned differently

Would a moon orbiting a planet that had no atmosphere glow red during a total eclipse? why or why not?

No, the moon glows red because of the atmosphere when the sun covers the moon

Umbra

Zone of full shadow

penumbra

Zone of partial shadow

Photosphere

bright disk of the sun covered by the moon

for what reason may two successive full moons not be totally eclipsed?

can't be near nodes for 2 Full Moons

Which lunar phases would be visible in the sky at dawn? at midnight?

dawn: full, waning gibbous, third quarter, waning crescent midnight: first quarter (east), waxing gibbous (east), full (overhead), waning gibbous (western), third quarter (set at midnight)

As the Moon journeys from Full to New, the proportion of its illuminated side visible from Earth is (increasing/decreasing). This is known as (waxing/waning).

decreasing waning

How did lunar eclipses lead Aristotle to conclude the Earth is a sphere?

during a lunar eclipse, Aristotle looked up at the moon and noticed the curved shadow on the moon.

Why can the sun be eclipsed by two successive new moons?

earth and moon will change positions and will line up

Throughout the Lunar Cycle, the Moon will appear further (eastward, westward) in the sky at the same time each day. Therefore, to an earthbound observer, the time of day when the Moon is highest in the sky becomes progressively (earlier, later).

eastward later

prominence

eruption on solar surface seen within chromosphere

diamond ring effect

occurs when a small part of the photosphere can peek out from behind the moon

Explain why the moon can't be eclipsed when it is halfway between the nodes of the orbit.

only when a new Moon is near one of its nodes can a solar eclipse happen

About every two weeks the moon goes from Full to New and back again.Why don't we have eclipses every month?

orbit of the moon is not aligned exactly with the ecliptic. (Moon's orbit is tilted)

Perigee

position closest to Earth

Apogee

position furthest away from theEarth

A 360 degree revolution of the moon is called what?

sidereal

What is the difference between sidereal and synodic period?

sidereal - time it takes to take 360 degrees around the Earth Synodic - time it takes for Moon to complete one cycle of phases (New Moon - New Moon)

annular eclipse

sun is almost completely covered by the moon, leaving only the ring around the sun visible

eclipse season

sun is close to a node in the moon's orbit

Why isn't the corona visible during a partial or annular eclipse?

sun light is so bright, can't see it

Corona

sun's faint outter atmosphere

Could a solar powered spacecraft generate any electricity while passing through Earth's umbral shadow? penumbral shadow?

umbral: No, completely dark, no sunlight penumbral: yes, part of the sun is still visible which means it can get SOME energy from the little light