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
