When the complete moon appears tomorrow (Thursday, March 14), it will present a remarkable view for observers in Aotearoa New Zealand. People residing on the eastern coastline of Australia should also find it worthwhile to take a glance.
Instead of appearing fully illuminated, the Moon will be midway through a lunar eclipse, which marks the first of two such events happening this year.
New Zealanders can look forward to seeing the Moon emerge entirely within Earth’s shadow, causing it to turn red rather than go dim. This phenomenon is popularly known as a "blood moon."
On the eastern seaboard of Australia, totality will occur while the Moon remains beneath the horizon; once it ascends, only partial shadow will be visible.
A crimson moon within Earth's shadow
During a full moon, the Sun and the Moon sit on opposing ends of the celestial sphere with Earth right at the center. This alignment allows Earth to project a substantial shadow that blocks sunlight from illuminating the Moon.
Nevertheless, during most full moons, we do not observe an eclipse due to the Moon's orbital tilt, which is approximately five degrees relative to Earth's orbit around the Sun. In many months, when the full moon occurs, it moves either above or below Earth's shadow. However, two times each year, the Moon's trajectory causes it to through the shadow instead.
When the Moon completely enters the umbra, it appears red solely because of Earth’s atmosphere.
The first eclipse from the Moon
The Blue Ghost Mission 1 Which touched down on the Moon on March 2, this mission will be the first to capture images of an eclipse from the lunar surface. While we observe the lunar eclipse here on Earth, the Blue Ghost 1 lander will simultaneously witness a total solar eclipse as our planet passes in front of the sun.
If you were on the Moon during totality and looked up at the Earth, you would see the atmosphere glowing like a red ring surrounding our planet.
Only the lower-wavelength red sunlight penetrates the atmosphere as the blue light gets dispersed. This phenomenon also explains why sunsets exhibit shades of red, orange, and pink.
Significantly, the atmosphere also bends or refracts the light, directing it into Earth’s shadow and causing the Moon to turn red.
Where and when to observe
Watching lunar eclipses is spectacular—totally harmless and doesn't require specialized gear. Given that the Moon will appear close to the horizon, ensure you have an unobstructed vista towards the east, possibly from a elevated location. This celestial show unfolds gradually, making it perfect for enjoying with companions.
As this eclipse occurs during moonrise, you can utilize the website for information. timeanddate.com To verify the time of moonrise specific to your area and also to calculate the eclipse magnitude, which indicates the extent to which the Moon will be covered by shadows.
An eclipse with a magnitude of 1 or greater indicates that the Moon is completely within the Earth's shadow, reaching total eclipse stage.
If it is below 1, it indicates the largest portion of the Moon’s diameter that gets covered during the eclipse. Picture a line running through the center of the Moon; the position where the shadow meets this line signifies the magnitude of the eclipse.
In New Zealand, the Moon will ascend during the total phase of the eclipse. As you move toward the northern regions, the duration of totality increases. Once the Moon exits the Earth’s shadow, twilight will conclude, leaving the night sky clear and dark for observing the remainder of the eclipse.
Along the eastern seaboard of Australia, the eclipse will appear against the vibrant twilight sky. This will pose significant challenges for observers in southern New South Wales, Victoria, and Tasmania, as merely a fraction of the Moon will be obscured.
Trick of the eye
However, that’s not all. Observing the Moon when it hovers near the horizon introduces a fascinating phenomenon known as the Moon illusion.
Our minds deceive us into perceiving the Moon as significantly larger than it actually is. However, if you use your thumb to block out the Moon when it's near the horizon and compare it with how it looks later in the night when it has risen higher, you'll notice that the Moon's size remains unchanged.
The illusion probably happens because we naturally assume the The sky has a domed shape. And since the Moon appears nearer when it's directly above us and more distant when it's close to the horizon. Just like how a bird seems to vanish as it flies further away.
However, the Moon is significantly more distant than a bird; its position remains constant throughout the night.
When our brain perceives the Moon closer to the horizon, it leads us to believe it is more distant. The Ponzo illusion explains this phenomenon, showing how we're misled into perceiving the Moon as larger at these times. In the following image, both Moons are identical in size; however, the perspective created by the railway lines tricks our mind into seeing the lunar disc near the horizon as being significantly larger due to the apparent distance.
If you miss this eclipse, the next total lunar eclipse occurring in 2025 will be visible in the early morning of September 8.
It will be observable throughout all of Australia, whereas New Zealand will witness the partially obscured Moon as it sets during sunrise; nearly the reverse scenario compared to tomorrow’s eclipse.
Tanya Hill does not have any employment, consulting relationships, share ownership, or received funds from any entity that could gain from this article. She has declared no additional affiliations apart from her academic position.
