Any astronomers out there???

[Nicos]

OK- I have a question!!!

I've been looking at full moon dates and had a bit of a surprise....

I always believed that a lunar month was 28 days...and therefore this would go hand in hand that the full moon would be exactly 4 weeks apart.
That would mean the full moon would infact fall on the same day of the week each time.
So...having just looked at the 2010 full moon dates I was shocked to see that this isn't the case...and that there were only 12 ( not 13) full moons in 2010

How come my childhood belief - finally checked- seems to be a load of old cobblers???

Here -take a look!..
2010 MOON PHASES

well????

[zazen999]

It's like QI in here sometimes.....

[binley100]

My brain hurts..............

[Capsid]

The orbit duration is 27.3 days, slightly less than 28 days.

I've heard that some people think the moon only appears at night.

[bobleponge]

I've heard still others say that the earth is round as well!!

I think Capsid's reason is the one I would have said, one orbit is slightly less than 28 days, which accounts for the leap year.

[zazen999]

I've heard that some people think the moon only appears at night.

[Nicos]

BUT...how does that explain why Feb/March and Nov/Dec full moons were 30 days apart??( see the chart I linked)..and not 28 days ???

[zazen999]

This October - there are 5 Fridays, Saturdays and Sundays.....haven't had that for years [according to Stuart Maconie just now].

[Capsid]

OK, I misunderstood your post. The full moon occurs every 29.53 days due to the way the earth rotates around the earth and the earth rotates around the sun. This called the synodic month.

While the moon is orbiting the earth, the Earth is progressing in its orbit around the Sun. This means that after completing a month the Moon must move a little farther to reach the new position of the Earth with respect to the Sun. This is called the synodic month. There are on average 12.37 full moons a year.

[Caro]

This October - there are 5 Fridays, Saturdays and Sundays.....haven't had that for years [according to Stuart Maconie just now].

My dad said he read that in the newspaper. So I looked at the calendar, and only had to go back as far as January - this year! So I don't understand what that is all about?

[OllieMartin]

I've heard still others say that the earth is round as well!!

I think Capsid's reason is the one I would have said, one orbit is slightly less than 28 days, which accounts for the leap year.

It's the number of rotations the earth makes before making one 'full' rotation of the sun. (It doesn't make a true full rotation for 26,000 years as the orbit shifts slightly each time).

[zazen999]

My dad said he read that in the newspaper. So I looked at the calendar, and only had to go back as far as January - this year! So I don't understand what that is all about?

An October with 5 I think.......

[Hilary B]

Even an October which starts on a Friday happens 4 times in 28 years (usually 6 years apart but at one point it is 11 years instead). The really rare calendar phenomenon only happens with the Chinese calendar.