The moon is going to be much larger and much brighter than normal on Monday evening. This is know as a “supermoon”.
On Monday 14th November, the moon is going to look much bigger than it usually does. In fact, it’s going to appear the largest it has since 1948 – 3 years after World War 2. The “supermoon” will look roughly 30% brighter and 14% bigger when compared with a typical full moon. It’s definitely going to be worth your while stepping outside and taking a look, assuming you have clear skies.
So, what exactly IS a supermoon, and what cause it?
The moon doesn’t orbit around the earth in a perfect circle. The shape it follows is know as an ellipse. Similar to that of a cirlce, although it is longer than it is wide. The result of this uneven shape is that the distance between the moon and the earth isn’t constant and fluctuates all the time. When the moon is at it’s closest (perigee), the moon is 31,068 miles closer the us than then it is at it’s furthest point from earth (apogee).
At the same time, we on earth are able to see the moon through various phases. These are full, crescent, waning and waxing. These phases depend on which way the moon is facing.
These two coinciding phenomena don’t always occur at the time time. But when they do, we get what astronomers refer to as a “supermoon”. This is also known scientifically as a perigee full moon. This occurs roughly every 14 full moons, Jim Lattis, an astronomer at the University of Wisconsin Madison, notes.
To be sure, this isn’t an enormous difference compared with a regular full moon. Neil deGrasse Tyson has called the frenzy around supermoons overblown. “If you have a 16-inch pizza, would you call that a super pizza compared with a 15-inch pizza?” he said on the StarTalk radio show.
But what makes this supermoon particularly unique?
The moon will appear slightly larger than it has in decades because of mere chance. The moon will reach fullness just three hours after perigee on November 14. Because perigee and the full moon are so closely timed, this full moon will be the largest (relative to our perspective on Earth) since 1948. The next-closest supermoon will be in 2034, as NASA reports.
Again, though, the differences in size between a really close supermoon and a typical one would be are pretty negligible. The full moon Monday will be just 30 miles closer to Earth than the last record in 1948, National Geographic reports. In astronomical terms, that’s tiny.
The moon will also be a bit brighter than usual — also due to the fact that it will be a bit closer to the Earth.
And if you miss it, fear not. We’re currently in a run of supermoons, and there will be another on December 14 (it won’t be quite as big). After that, we’ll have to wait until December 2017 for the next one.
Correction: This article originally misstated the how the moon’s phases occur. They do not occur due to the moon’s passing in and out of the Earth’s shadow. Rather, they’re due to the changing angles between the sun, Earth, and moon.