As part of our imaginative lives for thousands of years, the moon is embedded into song, story and poetry. But Wednesday morning, our silvery satellite will become the focus of renewed attention and for multiple reasons.
Lunar specialists say it will be a blue moon and a red moon. It will give us a lunar eclipse. And if that were not enough, it will also be a supermoon.
In order to make each of those events geometrically and astronomically possible, it will be a full moon.
By now, many of us are familiar with each of those celestial ornaments and descriptions. But seldom do we have a chance to experience them all together.
A blue moon is the second full moon in a month and is essentially metaphorical, not some visual characteristic. But calling Wednesday's full moon a red (or blood) moon recognizes that the moon is, indeed, expected to be tinged with red.
In a lunar eclipse, rays of red light pass through the Earth's atmosphere to reach the surface of the moon. On Wednesday, specialists say, Washington will be able to see a partial lunar eclipse starting at 5:51 a.m. and continuing until the moon sets in the west about 7:15 a.m.
We have come to apply the term supermoon to one that is full but that looks bigger and brighter than the normal full moon, which occurs about once a month.
It looks bigger and brighter because it happens to be full at just about the time it makes its closest approach on a given monthly orbit.
Essentially, as it travels around the Earth each month, the moon reaches points where its distance from the Earth is the greatest and where its distance is the least.
This characterizes an orbit that is not a circle, which would always keep it at the same distance from Earth. Instead, the moon traces out a geometric figure known as an ellipse.
At a time like this, when the moon, in addition to all else, is reaching its closest point on its elliptical orbit, it may be worth noting that Washington has a huge piece of prominent parkland that is laid out in the shape of an ellipse.
The grassy expanse between the White House and the Washington Monument is called the Ellipse, and with reason. It is laid out as a geometric ellipse, according to a study by mathematician Clark Kimberling, a professor at the University of Evansville. He quoted records showing an east-west axis of about 1,060 feet and a north-south axis of about 150 feet less.
If the earth were at the center of the Ellipse, and the perimeter of the Ellipse represented the orbit of the moon, then a supermoon would come when the moon was full and near the site of the National Christmas Tree.