A particularly super lunar event arrives early Wednesday
The first lunar eclipse of 2021 will occur during the early hours of May 26. But it’s going to be a particularly super lunar event, because it’s going to be a super moon, a lunar eclipse, and a red blood moon all at the same time. So what does all of this mean?
What is a super moon?
A the super moon is happening when a full or new moon coincides with the moon’s closest approach to Earth.
The Moon’s orbit around the Earth is not perfectly circular. This means that the distance between the Moon and Earth varies as it circles the planet. The point closest to the orbit, called perigee, is roughly 28,000 miles closer to Earth than the point furthest from the orbit. A full moon that happening near the perigee is called a supermoon.
So why is this great? The relatively close proximity to the Moon makes it appear a bit larger and brighter than usual, although the difference between a super moon and a normal moon is usually difficult to notice unless you are looking at two images side by side. .
How does a lunar eclipse work?
A lunar eclipse occurs when the Earth’s shadow covers all or part of the Moon. This can only happen during a full moon, so first of all it helps to understand what makes a full moon.
Like the Earth, half of the Moon is lit by the sun at all times. A full moon occurs when the Moon and the Sun are on opposite sides of the Earth. This allows you to see the entire illuminated face, which looks like a round disc in the night sky.
If the Moon had a totally flat orbit, each full moon would be a lunar eclipse. But the Moon’s orbit is tilted about 5 degrees from Earth orbit. So, most of the time, a full moon ends a little above or below the shadow cast by the Earth.
But twice in each lunar orbit, the Moon is on the same horizontal plane as the Earth and the Sun. If this matches a full moon, the Sun, Earth, and Moon will form a straight line, and the Moon will pass through Earth’s shadow. This results in a total lunar eclipse.
To see a lunar eclipse, you must be on the night side of Earth while the The moon passes through the shadows. The best place to view the May 26 eclipse will be the mid-Pacific Ocean, Australia, the east coast of Asia, and the west coast of the Americas. It will be visible over the eastern half of the United States, but only in the very early stages before the moon sets.
Why does the moon look red?
When the Moon is completely covered by Earth’s shadow, it darkens, but does not turn completely black. Instead, it takes on a red color, which is why total lunar eclipses are sometimes referred to as red or bloody moons.
Sunlight contains all the colors of visible light. The gas particles that make up the Earth’s atmosphere are more likely to scatter blue wavelengths of light while more red wavelengths pass through. It’s called Rayleigh scattering, and this is why the the sky is blue and sunrises and sunsets are often red.
In the case of a lunar eclipse, red light can pass through Earth’s atmosphere and is refracted – or bent – towards the Moon, while blue light is filtered out. This leaves the moon with a pale reddish tint during an eclipse.
Hope you can go see this awesome lunar eclipse. When you do, now you’ll know exactly what makes a show so special.
Shannon Schmoll is the director of the Abrams Planetarium in the Department of Physics and Astronomy at Michigan State University in East Lansing, Michigan. This document was first published by The conversation – “Super moon! Lunar eclipse of red blood! Everything is happening at the same time, but what does that mean?“