northgawx

The last widely visible total lunar eclipse over the US came over 3 years ago in January of 2019. That changes tonight with a blood moon on its way, and this one could be more impressive than usual thanks to volcano fallout.

If the weather cooperates, we will have a grand celestial show starting just before 10:30PM. The graphic below from NASA shows the timing of various stages of the eclipse. The big show stradles midnight with totality beginning at 11:29PM and ending at 12:54PM. For roughly one hour before and after we will see the moon enter and exit the Earth’s shadow.

There are two main phases to each lunar eclipse: the penumbral and umbral phases. This time the penumbral eclipse will begin at 9:32PM EDT and the umbral phase will begin at 10:27PM EDT. The penumbral phase isn’t particularly impressive, but the umbral phase is obvious as soon as it starts.

The two phases of the eclipse look very different from Earth. When the moon is in the penumbra, or outer shadow, it appears only slightly darker. This phase is only noticeable when it is “deep”, or close to the umbra. The umbra is the full shadow cast by the Earth. When the moon moves into this region there is no sunlight reaching it directly. That doesn’t mean it disappears, though. In fact it becomes quite beautiful. Total lunar eclipses are known as “blood moons” because of the deep red color.

This deep red color is caused by light being refracted through the Earth’s atmosphere. Essentially you are seeing all the sunsets and sunrises being reflected off the moon’s surface all at once. No cameras have ever seen a lunar eclipse from the moon, but the Earth would appear black with a bright red glow emanating from all sides and the sun’s corona (outer atmosphere) visible all around. I have no doubt it would be a beautiful sight.

This year, the total phases may be a bit darker than normal. Back on January 15 the Tonga volcano eruption became the most powerful in over a century. This sent millions of tons of particles into the Earth’s atmosphere, a large amount of which are still floating around in the upper atmosphere. These particles will almost certainly have an impact on the eclipse, mainly causing some darkening of the total phase. The moon may appear a darker red than usual, so that will be something to keep an eye out for as the eclipse progresses.

Be sure to head out and take a look at the first blood moon of 2022. The next will come in November when temperatures likely won’t be quite so pleasant.