Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: neilep on 04/03/2010 14:33:18

Title: Does The Moon Have A Day and a Year?
Post by: neilep on 04/03/2010 14:33:18
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I think it does and would I be right in assuming that it's the same length of time as a day and a year on Earth ?

....or does it use the Earth as it's focal point for a day and a year ?

whajafink ?



Neil
Is There Noon On the Moon ?
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Title: Re: Does The Moon Have A Day and a Year?
Post by: BenV on 04/03/2010 14:59:08
Well, assuming you mean a "day" to be the time it takes to complete 1 rotation around it's own axis, and a "year" to be the time taken to rotate around the body it's orbiting (i.e. the Earth), then the moon's days are the same length as it's years - 1 month.

But if you are thinking of it from a heliocentric perspective - it's days would still be an Earth month, but it's years would be roughly the same as Earth years.
Title: Re: Does The Moon Have A Day and a Year?
Post by: Robro on 04/03/2010 19:08:58
Cool photo!
Title: Re: Does The Moon Have A Day and a Year?
Post by: Soul Surfer on 04/03/2010 21:44:56
yes day on the moon lasts around 28 of our days and a year on the moon is about 13 of its days  we call them months.
Title: Re: Does The Moon Have A Day and a Year?
Post by: neilep on 04/03/2010 23:47:39
Cool photo!

Thank ewe Robro
Title: Re: Does The Moon Have A Day and a Year?
Post by: neilep on 04/03/2010 23:52:38
Thank you all for your clarification..

As Ben put it..heliocentric perspective is the way it goes.


A further question then if I may.....

Does the Sun have days, months & years ?
..presumably it does not have a heliocentric perspective ?
Title: Re: Does The Moon Have A Day and a Year?
Post by: Soul Surfer on 06/03/2010 23:30:51
The rotation period of the sun is about 25 days so that is what is best described as a day on the sun.  the concept of a year does not work but the sun is a somewhat erratic variable star with a total period of approximately 22 years  this includes two peaks and two minima of sunspot activity with alternating polarities of the magnetic fields in the sunspots.  we are just coming out of a sunspot minimum at the moment and this has lasted rather longer than normal and was staring to cause a bit of an alarm because a few hundred years ago there was "the little ice age" when sunspots disappeared for a long time and the weather was particularly cold.