This month’s full moon also occurs a mere nine hours after Earth’s only natural satellite passes its closest point. July’s full moon is therefore, the closest, biggest and brightest of 2022.
Don’t get too excited.
On Thursday morning the distance between Earth and the moon is just 200km less than it was last month.
Some will be celebrating a so-called ‘‘supermoon’’ on Thursday. I am not particularly keen on this term. It was originally coined by an astrologer and in my view causes much unnecessary hype in the media.
There is nothing particularly super about this month’s full moon. It is difficult to discern the changes in lunar size and brightness at different full moons with the naked eye.
Many people think that the moon is larger when it is closer to the horizon than when it is higher in the sky.
This is actually a misconception, called the moon illusion by astronomers. The size of the moon remains constant on any particular night.
You can prove this for yourself by taking a picture of the moon as it rises, and taking another when it is higher in the sky with the same camera set-up. When you compare the pictures you will find that the moon is exactly the same size.
One explanation for the moon illusion is that our eyes are tricked by the fact that when the moon is near the horizon we can compare it with things whose size we can relate to.
When it is higher in the sky the lack of available comparators fools our brain into thinking the moon has shrunk.
In Dunedin, the moon rises in the southeast at 4.03pm on Wednesday. Moonset is in the southwest at 8.51am on Thursday.
Why not head out at either of those times and watch the moon rise, or set, over a familiar horizon? See if your brain is fooled by the moon illusion.
