Looking up into the night sky with our telescope not only gives us some excellent views but leads to many questions. When we look into the night sky at the brightest object and or closest neighbor, the moon, we may ask how long it takes the moon to orbit around the earth.
It takes just short of a calendar month, 27.3 days, for the moon to orbit around the Earth. However, it takes 29.5 days for the moon to go from new moon to new moon.
Ok, so we know how long it takes the moon to orbit around the earth, but this may have you asking a few more questions.
Why does it take 28 days for the moon to orbit Earth?
The question then comes to why does it take 28 days for the process to happen.
As the moon orbits around the earth over the 28 days, the moon is tidally locked into the earth’s position. So we always see the same side of the moon and never see the dark side of the moon.
So as the earth moves on its axis, so is the moon moving on its axis and because they are tidally locked. It takes the same amount of time to rotate us every month, 28 days.
During its 28 days orbiting, the moon changes shape in the night sky. The reason for this is because only this section of the moon’s surface is sunlit. These different shapes are called the moon phases and repeat every 29.5 days.
How long does it take for the Earth to revolve?
A ubiquitous question, but it’s not simple to answer unless you are comparing it to something. With no frame of reference, it’s impossible to answer the question on the revelations of earth.
If we use the center of our planet as a frame reference, we know that the earth revolves every 23 hours, 56 minutes, and 4.09053 seconds. This is called a “sidereal period,” and the circumference of the earth is approximately 40,075 kilometers. With all this knowledge, it has been worked out that the equator moves at about 1,000 MPH.
When we are in school, we learn about the earth revolving around the sun. We learned that earth revolves around the sun over 365 days, 5 hours, 59 minutes, and 16 seconds period. The time it takes this to happen is what we call a year on earth.
How many times will the moon orbit around the earth in one year?
Again like all the questions we have answered above its was not as simple as the answer may first appear.
The moon makes a complete orbit around the earth every 27.3 days. So this means that the moon orbits the earth approximately 13 times in a calendar year.
Where the complexity comes in is what measurement we use to determine a full orbit of the earth. The most common is the “sidereal period” or “sidereal month,” where stars are used to measure movement, which is thought to be the most accurate 27.3 day period. The second method uses a “synodic month,” which measures how long the moon takes to get back to the same moon phase 29.5 days.
As you can see, one is in 27.3 days, and the other is in 29.5 days. Much debate about which of the two is most accurate is commonly regarded as the 27.3 sidereal months to be the most accurate.
Does the moon orbit around the sun?
Does the moon orbit around the sun? Yes, would have to be the answer. The moon orbits around the sun at the same time it orbits the earth. A simple way to put it is that all three objects, the sun, moon, and earth, are interacting with each other all at the same time. All this interaction between the sun, moon, and earth is called “physics”. So yes, the moon orbits the sun, but for some, that would be too much of a simple answer, and would need to dig deeper into the whole process’s physics.
I hope you enjoyed my article about the moon’s rotation, and ultimately you got the answer to your question on how long it takes the moon to orbit around the earth.
This question throws you down rabbit holes of follow-on questions, and then they keep leading to more questions. The very reason that people who love to explore our solar system with a moon telescope love these wonders.
I aim to keep adding questions about our solar system to my site. I hope you explore our solar system and my site. I’m sure you will find many other articles answering questions that you will enjoy.