Our orbiting moon has a complex orbit, to be honest any object in space revolving around another has a complex orbit. To start with the moon's orbit is not circular but elliptical. This elliptical orbit brings the moon closer to earth during part of the orbit and further away during another part. The difference in the distance to the moon results in supermoons. Supermoons occur when the moon is closer and can appear to be up to 14% larger and 30% brighter.
The moon takes 27.2 days to complete it's orbit around the earth. This is known as the sidereal month, the time it takes for the moon to orbit a full 360 degrees. Because the earth is also revolving around the sun it takes slightly longer for the moon to go through all of it's phases. From new moon to new moon is 29.5 days and is called the synodic month. Our current 12 month calendar is based in part on the synodic month.
Imagine the elliptical path of the moon making a plane, this plane is tilted at a 5 degree angle compared to the axis of the earth. One of the great mysteries of our solar system is why the orbit of the moon is tilted, it is referred to as the lunar inclination problem. There have been numerous theories formed to solve the lunar inclination problem but none have stood up to long term examination, so far, it's a mystery.
When the sun, earth and moon are lined up in a straight line we have the opportunity to see either a solar eclipse or a lunar eclipse. This tilt makes the orbit of the moon only line up with the earth and sun twice per year. If the elliptical plane of the moon path were not tilted, we would see eclipses every month.
To further complicate the path of the moon, the elliptical plane of the path of the moon rotates around the axis of the earth. This rotation is called precession. Precession occurs slowly with the full rotation occurring every 18.61 years. This orbital rotation, precession, alters the windows of opportunity to see either lunar or solar eclipses. Each year, because of precession the date of potential eclipses changes between 19 and 20 days.
In an earlier post, Is the Sun Setting in the Wrong Place?, @nananini asked whether the moon always rose and sat in the same place. The answer is no but it may not be enough difference for most of us to notice. As we go through the seasons the sun sets further north in the summer and further south in the winter due to the tilt of the axis of the earth. Because the tilt of the earth is 23.5 degrees compared to the tilt of the lunar orbit of 5 degrees, the movement of the moon rising and setting will not be as pronounced. The best way to see the difference would be to take photos from the same location of a new moon rising and a full moon rising. It would be interesting to see the difference.
Wow, thank you.
Admittedly I need a science teacher and a couple props to visualize this. What we have learned to understand about the sun, moon and earth's rotation is fascinsting.
How this all works is amazing. Have never been too curious about how the earth began. When I see facts like this that prove the intricacies of them working together to sustain life....I can only say there is nothing mankind can create to compete with this 'technology'.
What we don't know about our universe is still a challenge. Those seeking to take on the challenge of all space secrets will undoubly discover many more inexplicable happenings!
Thanks again and I hope you enjoyed your research as much as I do the final product.
Have a great day.
It took me some time to figure out the jargon used by these scientist. Some of the stuff they write is horrible for anyone not in their field.
Some of it is probably bad if you are in their field. ☺