On Monday, November 14, the moon will be almost 30,000 kilometers closer to the Earth than it usually is. For astute gazers of the night sky it should offer a wonderful spectacle not seen since 1948.
On Monday, November 14, the moon will be at its closest distance to the Earth since 1948, giving the effect of an "extra-super moon”.
Although "supermoons” are quite common – usually occurring every 14 months – Monday's will be the closest in quite some time and won't return to a similar distance until 2034.
According to NASA, our planet's solitary companion will be just 356,509 kilometers from the surface of the Earth. That is some 27,891 kilometers closer than its average distance in the night sky.
Should the weather permit a clear sky, eagle-eyed gazers will note a moon 14 percent bigger than its usual size and far brighter than its normal reflection due to the Earth being closer to the sun at this time of year.
Although most may not notice much of a difference once the moon is at its highest point in the night sky, astronomers believe it will be apparent on the horizon. And it could be quite the spectacle.
"When you look at the moon when it's rising, there is this optical illusion where it looks bigger," Mark Bailey, astronomer and emeritus director of the Armagh Observatory in Northern Ireland, told AFP.
Pascal Descamps, astronomer at the Paris Observatory, agrees. "If you want to try to photograph it, choose a location where you'll get some nice terrestrial feature in the foreground,” he suggests.
"A well-known landmark such as a tower or a spire will provide a nice comparison, particularly if you stay back a bit and use a zoom or telephoto lens which will magnify both objects."
Plenty of opportunities
Of course, if clouds happen to crowd Monday's sky there will be other opportunities to see the spectacle in full view. According to Noah Petro, deputy project scientist for NASA's Lunar Reconnaissance Orbiter (LRO) mission, the supermoon should be visible for a number of days.
"I've been telling people to go out at night on either Sunday or Monday to see the supermoon,” he said. "The difference in distance from one night to the next will be very subtle, so if it's cloudy on Sunday, go out on Monday. Any time after sunset should be fine. Since the moon is full, it'll rise at nearly the same time as sunset, so I'd suggest that you head outside after sunset, or once it's dark and the moon is a bit higher in the sky. You don't have to stay up all night to see it, unless you really want to.”
One of the most striking features of the moon is the gravitational effect it has on the Earth's oceans. Due to the elliptical nature of the moon's orbit of the Earth, the ocean levels tend to rise and fall in the form of tides and the patterns that they follow.
Monday's supermoon should then suggest a higher tide, meaning possible minor flooding in part but most notably bigger waves throughout the world.
While surfers may enjoy the larger waves and added brightness, should they choose to go out at night, the effects of a supermoon on tidal patterns has often been blamed for natural disasters.
In 2011 NASA was forced to dismiss the theory that a tsunami and earthquake that hit Japan was due to an upcoming supermoon, while coastguards in the United Kingdom suggested that the lunar event was responsible for five fishing vessels running ashore off the coast of the Isle of Wight in the same month.
"The effects on Earth from a supermoon are minor, and according to the most detailed studies by terrestrial seismologists and volcanologists, the combination of the moon being at its closest to Earth in its orbit, and being in its 'full moon' configuration (relative to the Earth and sun), should not affect the internal energy balance of the Earth since there are lunar tides every day," said Jim Garvin, chief scientist at NASA's Goddard Space Flight Center, at the time.
"The Earth has stored a tremendous amount of internal energy within its thin outer shell or crust, and the small differences in the tidal forces exerted by the moon (and sun) are not enough to fundamentally overcome the much larger forces within the planet due to convection (and other aspects of the internal energy balance that drives plate tectonics)."