Photo credit: www.cntraveler.com
This week, the night of March 13 extending into the morning of March 14, a captivating astronomical phenomenon will occur: a total lunar eclipse. This event, observable for over three hours, will be visible throughout nearly all of North America, Central America, and the majority of South America. In western Africa, the moon will set while still experiencing the eclipse, and in the far eastern regions of Russia, it will rise already in the midst of the event.
One of the appealing features of a lunar eclipse is that it can be observed without any special equipment. All that’s needed are your eyes and a clear view of the night sky. You might not even have to leave urban areas, although light pollution could make it difficult to see the fully eclipsed moon. Nevertheless, if you have access to a telescope or binoculars, your experience will be greatly enhanced, allowing for a closer view of the celestial spectacle. To truly appreciate this cosmic event, it helps to understand the intriguing science behind lunar eclipses, including the reason the moon appears to take on a reddish hue—a phenomenon nicknamed the “blood moon.” In this article, we will explain what to expect in the night sky during the upcoming eclipse; all you have to do is look up.
Observing Earth’s shadow on the moon
It’s an interesting concept to consider that Earth casts a shadow, particularly since there’s no tangible surface in space for it to fall upon. Essentially, a shadow forms when an object blocks light. Thus, if you were positioned in space directly behind Earth relative to the Sun, our planet would obstruct the sunlight, casting a shadow.
A total lunar eclipse occurs relatively infrequently because the moon generally travels above or below Earth’s shadow, given the tilt of its orbit. However, once or twice a year, the alignment between the sun, Earth, and moon allows the latter to move into this shadowed area, creating the opportunity for an eclipse.
As Earth is spherical, its shadow on the moon is circular. When the moon begins to move into the shadow, the edge of its disk starts to darken, marking the onset of the partial eclipse. Over a few minutes, this darkening spot expands into an arc, creeping over the lunar surface until it completes its journey, transitioning to its crescent form. Ultimately, the moon becomes fully enveloped in Earth’s shadow, a phase known as totality.
The phenomenon of blood moons
During totality, which can last for more than an hour depending on the moon’s position in Earth’s shadow, an extraordinary effect occurs. Rather than disappearing into darkness, the moon takes on a striking orange or blood-red hue, giving rise to the term “blood moon.”
This coloration is explained by the interaction of sunlight with Earth’s atmosphere. The atmosphere acts as a filter; as sunlight travels through it, the shorter blue wavelengths are scattered, while the longer red wavelengths dominate. When viewed from the moon, Earth’s atmosphere appears as a bright ring, and during a lunar eclipse, light that passes through this atmospheric layer becomes highly reddened. This is akin to how sunrises and sunsets appear intensely colored from our perspective on the ground, but here the effect is heightened as the moon experiences countless sunrises and sunsets all at once!
The stages of a lunar eclipse
As the moon continues its orbit, it eventually begins to exit Earth’s shadow. The phase of totality concludes, and the partial eclipse reverses its course: the last section of the moon to be engulfed is the first to be released from the shadow, until the moon is fully illuminated once more, free from Earth’s shadow.
Source
www.cntraveler.com