What makes certain lunar eclipses so special? (Beginner)

What makes certain eclipses stand out more than others? The eclipse of 2019 was advertised as a "rare" and "perfect" lunar eclipse that only happens once every 19 years, and was supposedly redder than the next lunar eclipses will be. Was this eclipse redder than any others from the past, or not? Will the lunar eclipse of 2021 be less red? Is a Lunar Eclipse's maximum better to watch when they are longer or shorter? I ask because the next total lunar eclipse of 2021 will be 15 minutes. Will it still be worth seeing? 

To understand why people cared so much about the eclipse in January of 2019, we can discuss its name: "Super Blood Wolf Moon".

The "Super" comes from the term "supermoon". The Moon's orbit isn't perfectly circular, so there are places in its orbit where it is closer to the earth than average. When the moon is slightly closer to us, it looks slightly bigger, in the same way that signs on the highway appear much smaller in the distance than when you are about to pass them. When the full moon happens near the closest position in the moon's orbit, the full moon appears slightly larger and slightly brighter than normal, making a "supermoon". Despite the fact that this difference physically occurs, it would be very difficult for us to detect by eye. The moon is only about 30% brighter than average during the most extreme supermoons - a difference that is very difficult to detect by eye!

The "Blood" comes from the fact that the moon appears red-brown during a total lunar eclipse. The moon appears this color because of the way light from the sun passes through Earth's atmosphere. During an eclipse, the Earth's shadow intercepts the light from the sun that usually reflects on the moon. In the Earth's atmosphere, red light is refracted into the shadow, for the same reason that the horizon looks red at sunset. When there is a partial eclipse, it is much harder to see this red tint because the reflected light of the moon that isn't blocked by the Earth's shadow is much brighter. 

Finally, the name "Wolf Moon" is a name that comes from tradition. Indigenous tribes in North America - particularly the Algonquin tribes - tracked time using the full moons, and named the full moons of the year after seasonal events. Every full moon has a similar, seasonally-appropriate name - some moons have multiple names, as the tradition was used by numerous peoples and eventually co-opted by settlers. For instance, May's full moon is called the "Flower Moon". 

All this to say - it's not always a single thing that makes eclipses like the one in January 2019 stand out, but the fact that they combine multiple unusual occurences in the same event. If you enjoyed watching the last lunar eclipse, you will probably also enjoy watching the next, even though it may be (unnoticeably) dimmer.

As for the length of an eclipse: in a lunar eclipse, the "maximum" of a total eclipse occurs when the moon is completely covered by the darkest part of the Earth's shadow. The length of a lunar eclipse maximum only depends on the alignment of the moon and the Earth's shadow, so the length of maximum alone doesn't make it appear brighter or redder, etc. A longer lunar eclipse simply means the moon will appear red for less time, but it will look very similar, especially to the naked eye.

Most Popular

Our Reddit AMAs

AMA = Ask Me (Us) Anything