Northern Lights Now – On the night of January 20-21 sky watchers anywhere in the Americas and Western/Northern Europe are in for a treat as they have an opportunity to watch a full lunar eclipse. Weather permitting, viewers should be able to see the moon slowly edge into the Earth’s shadow, then turn red as it enters an hour long phase of full eclipse.
This eclipse also aligns with a super moon. That means the Moon is closer than normal or “at perigee.” The Moon has an elliptical orbit, so there are times when it is closer and and times when it is farther from Earth. Occasionally perigee aligns with a full moon or a new moon, when it does, the full moon is labeled “Super.”
Tides are higher and lower than normal during perigee because the Moon is closer and exerts more gravitational force on the oceans. Tides are also higher (and lower) during full moons because the gravity of the Earth and Sun pull together. When these align, as they will be this weekend, it is called a King tide.
You may also see this full moon referred to as a Wolf Blood Moon. Each of the full moons throughout the year are given names. The January full Moon is often referred to as the Wolf Moon. It’s easy to imagine wolves howling at the moon in the dead of winter when clear dry air will make their howls carry farther.
Why does the Blood Moon Turn Red?
Great Question – once the moon is fully in the shadow of the Earth, the only light reflecting off the Moon has been refracted through the edges of the Earths Atmosphere. The atmosphere filters out most other wavelengths or colors of light. Red is the majority of the light that reaches the Moon and reflects back, so the eclipsed Moon will look Red (or Pink, or Orange). This is actually the same process that makes sunsets look red on Earth. In fact, you can imagine that if you were standing on the Moon during a lunar eclipse, the sun would “set” behind the Earth, then you would see a ring of sunset that is mostly red from every part of the horizon of Earth. Yep – Cool!
Why does it always seem like an eclipse happens during a full moon?
Because it does! The only time the Moon can fall into the shadow behind the Earth is when it is exactly opposite the Sun. That can only happen during a full Moon because the Moon is full when it is opposite the Sun. Similarly, Solar eclipses can only happen during new moons, when the moon is directly between the Sun and the Earth. In a solar eclipse, the Moon casts it’s shadow on a portion of Earth. If you are in that shadow, you see a full eclipse.
It’s actually slightly more likely you will see an eclipse if it falls during perigee. During perigee, the Earths shadow is slightly bigger at the Moon. That makes for a longer transit, and more of the Earth will be in a position to see the Moon completely eclipse.