# Why are solar eclipses more common in the southern hemisphere?

I've seen the claim that solar eclipses on Earth are more common in the southern hemisphere than the northern hemisphere and would like to understand why and if that is the case? Does it relate more to the position of the moon relative to the earth or more to how the earth rotates the sun or is this just hogwash?

http://science.slashdot.org/story/12/09/17/1152238/curiosity-rover-sees-solar-eclipse-on-mars

• Could you provide a link for the claim? I can't see immediately any reason that should be so and I don't see any mention of it on Wikipedia. Sep 17, 2012 at 15:09
• Warrick, the claim is made here: science.slashdot.org/story/12/09/17/1152238/… (Sorry, I couldn't work out how to make this post appear below Warrick's.)
– user12305
Sep 17, 2012 at 18:42
• @abano you will need to get 50 reputation to be able to post comments. (Except that you can always comment on questions you ask and their answers.) Sep 17, 2012 at 19:29
• Can you clarify what you mean by "more common?" Do you mean "seen by more humans" or "occurs with greater frequency" or something else?
– user11266
Sep 17, 2012 at 19:59
• I assume occurs with greater frequency, I didn't make the claim, but if it were seen by more humans then it would make perfect sense in the opposite direction of the claim since the land masses are weighted to the northern hemisphere. If that is what they meant, it would be rather misleading the way it was written and backwards. Sep 17, 2012 at 20:15

I see no reason for it, and no mention of it anywhere else.

Indeed, if you look at the list of solar eclipses in the 21$^\mathrm{st}$ century, you'll see also a column containing the coordinates on the Earth's surface where the eclipse peak will be.

I took that column and put it in a text editor. I then counted the number of occurrences for $^\circ N$ and $^\circ S$, and I found

$$\matrix{ ^\circ N:& \mathrm{occurred\ 114\ times} \\ ^\circ S:& \mathrm{occurred\ 110\ times} }$$

So the statement on slashdot seems to be false (at least for the 21$^{\mathrm{st}}$ century).

You could repeat the process, taking only the total eclipses:

$$\matrix{ ^\circ N:& \mathrm{occurred\ 33\ times} \\ ^\circ S:& \mathrm{occurred\ 35\ times} }$$

from which we conclude the same.

You can repeat the same for the 19$^{\mathrm{th}}$, 20$^{\mathrm{th}}$, 22$^{\mathrm{nd}}$ and 23$^{\mathrm{rd}}$ centuries, with the same outcome: they occur just as frequently on the Northern as on the Southern hemisphere.

I realize this is not really a proof of any kind, but frankly, the burden of proof is not on my side here :)

• +1 for using the burden of proof. I really believe in this device making the every day life easier. Nov 27, 2015 at 22:24

I can't find any convenient statistics, but feel compelled to write something by the kneejerk answers and comments.

A solar eclipse needs to occur when the Sun is visible from that hemisphere. i.e. More eclipses should occur in northern and southern summers and this effect should be symmetric between hemispheres (though see below).

The Earth's orbit is slightly elliptical. Perihelion, when the Earth is closest to the Sun and the Sun has its largest apparent angular size in the sky, is about January 3rd. This is during southern summer. The peak to peak difference in angular size is about 3% over the year. This makes it more probable that the Moon can intercept some part of the Sun during southern summer, but less likely to totally eclipse it.

However, this small effect might be counterbalanced by the fact that the Earth moves quicker in its orbit during southern summer, making southern summer shorter by a few days.

Overall, I would therefore perhaps expect a small effect where there would be fewer total eclipses, but more partial eclipses in the southern hemisphere.

But either way, the notion is not to be summarily dismissed and you probably need statistics over millennia to see it.