How to measure the rotation period of the moon?

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Discussion Overview

The discussion revolves around the methods used to measure the rotation period of the Moon, specifically focusing on its own rotation (lunar day) rather than its orbit around the Earth (lunar month). Participants seek to clarify the concepts and find sources related to these measurements.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant inquires about how scientists measure the Moon's rotation period.
  • Another participant clarifies the distinction between the Moon's own rotation and its rotation around the Earth.
  • It is noted that the Moon's day is the same length as its lunar month (approximately 27 days, 7 hours, and 43.2 minutes), which is attributed to tidal friction leading to synchronous rotation.
  • Participants discuss that the Moon does experience slight rotation due to variations in its orbit, which can be observed through changes in shadows on craters.
  • Methods for measuring the lunar month are proposed, including timing the crossing of the Moon's edge with a bright star over a 28-day period.
  • For measuring the lunar day, one participant suggests measuring the angle to the edge of a crater relative to the Moon's edge.
  • There is a request for articles or sources related to these measurement methods.

Areas of Agreement / Disagreement

Participants generally agree on the length of the lunar day and month, as well as the concept of tidal friction. However, the discussion remains unresolved regarding specific methods and sources for measuring the rotation period.

Contextual Notes

Some assumptions about the methods of measurement and the effects of tidal friction may not be fully explored or defined, leaving room for further clarification.

suski
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anyone know how scientists measure the rotation period of the moon?
thank you!
 
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Do you mean it's own rotation (ie a lunar day) or it's rotation around the Earth (a lunar month)
 
its own rotation (lunar day)
 
im trying to find articles/sources on it..but haven't found any yet
 
The moons day is the same length as the lunar month (27 days 7 hours 43.2min) - that's why it always points the same face toward earth.
This isn't a coincidence, an effect called tidal friction means that gradually the Earth has slowed down the moon's rotation until it is now locked to Earth.
It does rotate a small amount because of small variation in the orbit, you can see this from small changes in the shadows on craters.
 
thanks!
but are there any methods to calculate/measure it?
 
Well the lunar month you just record the time that the edge of the moon crosses some distance bright star and then note the next time it crosses it 28days later.
For the day rotation you could measure the angle to the edge of some crater compared to the edge of the moon.
 
oh okok..
thanks a lot!
 
do u know where i can find info on this??
 

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