The Moon will be full, and at its nearest to Earth this year, on Wednesday July 13.
See the end note about enlarging illustrations.
Our scene shows the Moon coming up on the previous evening, because the nearest-in-moment occurs in the morning hours for America and Europe. You can see that the Moon will, in the coming hours, pass the point we’ve marked as the anti-Sun.
Twice or sometimes three times every year, there is a near-in Moon (“supermoon,” the media like to call it) because the Moon comes to its perigee, or nearest point of its elliptical orbit, close to a time when it also comes to its new or full position.
This is made clear in our graph of the Moon’s distance in Astronomical Calendar 2022.
The very wavy curve represents the Moon’s distance; the Moon is shown, to scale, at its new and full moments (and, in blue, its first and last quarter moments); a broad smooth curve connects the new Moons and another connects the full Moons.
The time of the July 13 perigee is 9:04 by Universal Time, which by clocks on distorted summer time show as 10:04 in Britain, 4:04 in North America’s Central time zone.
The perigee happens only 9.5 hours before the moment of full Moon.
Tides are caused mainly by the Moon, but the Sun, vastly larger and vastly more distant, adds a pull about half as strong. This is why the highest amplitude of tides comes at these two near-in Moons, slightly less than half a year apart.
The Thames will probably rise over our dock.
There is a heat wave also rising, but its amplitude may have more human than lunar contribution.
__________
ILLUSTRATIONS in these posts are made with precision but have to be inserted in another format. You may be able to enlarge them on your monitor. One way: right-click, and choose “View image” or “Open image in new tab”, then enlarge. Or choose “Copy image”, then put it on your desktop, then open it. On an iPad or phone, use the finger gesture that enlarges (spreading with two fingers, or tapping and dragging with three fingers). Other methods have been suggested, such as dragging the image to the desktop and opening it in other ways.
Sometimes I make improvements or corrections to a post after publishing it. If you click on the title, rather than on ‘Read more’, I think you are sure to see the latest version. Or you can click ‘Refresh’ to get the latest version.
This weblog maintains its right to be about astronomy or anything under the sun.
There have been warnings here about the upcoming ‘super moon’ high tides, particularly given that waterways are already at high levels as a result of the recent flooding.