This entry was posted on April 30, 2022 by Anne Helmenstine (updated on May 11, 2022)
The phase of the Moon or lunar phase is the sunlit shape of the Moon we see from Earth. Here are the names of the 8 phases of the Moon and a look at how they work. Also, learn how the phase of the Moon relates to lunar eclipses.
- In order, the phases are: new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter, and waning crescent.
- At a new moon, the Moon is between the Sun and the Earth.
- At a full moon, the Earth is between the Sun and the Moon.
- A total lunar eclipse only happens during a full moon, when the Earth is directly between the Sun and Moon..
- The new moon isn’t completely invisible because light reflected back from the Earth (Earthshine) weakly illuminates the Moon.
The Lunar Cycle
The phases of the Moon are a cycle that repeats each synodic month (~29.53 days) because of the changing positions of the Sun and Moon relative to Earth. There are a total of eight lunar phases.
- Principal Phases: The four principal lunar phases are new moon, first quarter, full moon, and third quarter (which is also called final quarter or last quarter).
- Intermediate Phases: The four phases that link the principal lunar phases are the intermediate phases. The intermediate phases are waxing crescent, waxing gibbous, waning gibbous, and waning crescent.
A waxing moon is one which is thickening in shape, while a waning moon is one which is thinning in shape. From full moon to new moon (or new moon to full moon) takes between 13 and 15 days.
Phases of the Moon
The cycle begins with the new moon, which appears larger until it reaches the full moon phase. Then, the moon appears thinner until the waning crescent disappears and becomes the new moon. Then, the cycle begins again.
- New Moon: The Moon is between the Earth and the Sun, so its only lit by light reflected from Earth.
- Waxing Crescent: The thin crescent thickens.
- First Quarter: Half of the Moon is lit because the Moon is 90 degrees relative to the Sun. This phase is called “first quarter” because the Moon is a quarter of the way through the cycle.
- Waxing Gibbous: The Moon is more than half lit.
- Full Moon: The moon is 180 degrees (in a line with the Earth and Sun) and is fully lit.
- Waning Gibbous: Over half the lunar surface is lit, but less is visible each night.
- Third Quarter: Half the Moon is lit. This is the half that was dark at first quarter.
- Waning Crescent: The sliver of the Moon thins.
Phases of the Moon in the Northern and Southern Hemisphere
No matter where you are on Earth, the phase of the Moon at any given time is the same. The same portion of the Moon is illuminated. So, the phase of the Moon is the same in the Southern Hemisphere as it is in the Northern Hemisphere. However, the orientation of the Moon is different. The Moon appears upside down in the Southern Hemisphere compared to its appearance in the Northern Hemisphere, which means the waxing and waning of the Moon appears to start from a different direction.
<!-MONUMETRIC Repeatable 2 D:300x250 T:300x250 M:300x250,320x50 START->
<!-MONUMETRIC Repeatable 2 D:300x250 T:300x250 M:300x250,320x50 ENDS->
| Moon Phase | Lit Portion Northern Hemisphere | Lit Portion Southern Hemisphere | Visibility | Average Moonrise | Average Moonset |
|---|---|---|---|---|---|
| New Moon | Moon in Sun’s shadow, lit only by earthshine | Moon in Sun’s shadow, lit only by earthshine | Nearly invisible | 6 am | 6 pm |
| Waxing Crescent | Right side 0%-50% lit | Left side 0%-50% lit | Late morning to after sunset | 9 am | 9 pm |
| First Quarter | Right side 50.1% lit | Left side 50.1% lit | Afternoon and early evening | noon | midnight |
| Waxing Gibbous | Right side 50%-100% lit | Left side 50%-100% lit | Late afternoon to most of the night | 3 pm | 3 am |
| Full Moon | 100% illuminated | 100% illuminated | Sunset to sunrise | 6 pm | 6 am |
| Waning Gibbous | Left side 100%→50% lit | Right side 100%→50% lit | Most of the night to early morning | 9 pm | 9 am |
| Third Quarter | Left side 50.1% lit | Right side 50.1% lit | Late night and morning | midnight | noon |
| Waning Crescent | Left side 50%→0% lit | Right side 50%→0% lit | Before dawn to early afternoon | 3 am | 3 pm |
Phases of the Moon Worksheet
Practice identifying lunar phases.
[worksheet Google Apps][worksheet PDF][worksheet PNG][answers PNG]
2022 Phases of the Moon and Dates
Here are the four principal phases of the Moon for 2022, with dates and times (Eastern time):
| New Moon | First Quarter | Full Moon | Third Quarter |
|---|---|---|---|
| Jan 2, 1:33 p.m. | Jan. 9, 1:11 p.m. | Jan. 17, 6:48 p.m. | Jan. 25. 8:41 a.m. |
| Feb. 1, 12:46 a.m. | Feb. 8, 8:50 a.m. | Feb. 16, 11:57 a.m. | Feb. 23, 5:32 p.m. |
| March 2, 12:35 p.m. | March 10, 5:45 a.m. | March 18, 3:17 a.m. | March 25, 1:37 a.m. |
| April 1, 2:24 a.m. | April 9, 2:48 a.m. | April 16, 2:55 p.m. | April 23, 7:56 a.m. |
| April 30 4:28 p.m. | May 8, 8:21 p.m. | May 16, 12:14 a.m. | May 22, 2:43 p.m. |
| May 30, 7:30 a.m. | June 7, 10:48 a.m. | June 14, 7:52 a.m. | June 20, 11:11 p.m. |
| June 28, 10:52 p.m. | July 6, 10:14 p.m. | July 13 2:37 p.m. | July 20,10:18 a.m. |
| July 28, 1:55 p.m. | Aug. 5, 7:06 a.m. | Aug. 11, 9:36 p.m. | Aug. 19, 12:36 a.m. |
| Aug. 27, 4:17 a.m. | Sept. 3, 2:08 p.m. | Sept. 10, 5:59 a.m. | Sept. 17, 5:52 p.m. |
| Sept. 25, 5:54 p.m. | Oct. 2, 8:14 p.m. | Oct. 9,.4:55 p.m. | Oct. 17, 1:15 p.m. |
| Oct. 25, 6:49 a.m. | Nov. 1, 1:37 a.m. | Nov. 8, 6:02 a.m. | Nov. 16, 8:27 a.m. |
| Nov. 23, 5:57 p.m. | Nov. 30, 9:36 a.m. | Dec. 7, 11:08 p.m. | Dec. 16, 3:56 a.m. |
| Dec. 23, 5:17 a.m. | Dec. 29, 8:20 p.m. |
Earthshine
You can still see a crescent moon and new moon because of earthshine. At these phases, the Earth is lit by the Sun. Sunlight reflects back from Earth toward the Moon, making it dimly visible.
Does the Moon Rotate?
You know the Earth rotates on its axis. Have you ever wondered whether the Moon does too?
What Is a Lunar Eclipse?
A lunar eclipse occurs when the Earth is between the Sun and Moon. So, a lunar eclipse only occurs during a full moon. The Earth blocks direct sunlight, so the illumination comes from light that bends around the Earth’s atmosphere and reaches the Moon. This makes a lunar eclipse appear orange or reddish.
- A total lunar eclipse occurs when the shadow of the Earth completely covers the Moon.
- A partial lunar eclipse occurs when the Earth’s shadow only partly covers the Moon.
The Earth comes between the Sun and the Moon at every full moon, yet lunar eclipses don’t happen very often. This is because the Moon’s orbit around the Earth is tilted with respect to the Earth’s orbit around the Sun. The Moon passes right through the Earth’s shadow approximately twice a year.
References
- Espenak, Fred; Meeus, Jean. “Visual Appearance of Lunar Eclipses“. NASA.
- Kutner, Marc L. (2003). Astronomy: A Physical Perspective. Cambridge University Press. ISBN 978-0-521-52927-3.
- Montenbruck, Oliver; Gill, Eberhard (2000). Satellite Orbits: Models, Methods, and Applications. Springer Science & Business Media. ISBN 978-3-540-67280-7.
- Naylor, John (2002). Out of the Blue: A 24-Hour Skywatcher’s Guide. Cambridge University Press. ISBN 978-0-521-80925-2.
