The moon travels around the Earth at 2,288mph, which means it can travel roughly its own diameter every hour. In one orbit around the Earth it travels 1,423,000 miles. The time it takes to do one orbit around the Earth is 27.32 days and this is known as a sidereal month. The time between full moons is 29.53 days and is known as a synodic month.
The difference in the two times is due to the fact that the Earth is also moving, but in relation to the Sun. Therefore the moon has to travel a little more than one full orbit before it is at the direct opposite of the Earth away from the Sun.
Its orbit around the Earth is not circular; it is elliptical in shape bringing it closer to the Earth at certain times. At its closest point (perigee) it is about 225,300 miles away while at its furthest point (apogee) it can be 251,900 miles away. If perigee occurs at the time of the full moon then it can appear about a third larger in the sky than if the full moon occurs at apogee. This event has been christened a Super Moon. The next Super Moon will occur on 3 December with perigee occurring the day after.
The full Super Moon of 14 November last year was the closest full moon since 1948 and it won’t come this close again until 25 November 2034.
Tonight, Friday 26 May, the opposite of a full Super Moon will occur. The moon will be at its closest perigee point at the same time as it is between the Earth and the Sun and is a new moon. Because the moon is new you won’t be able to see it but you may notice its effect. The moon’s gravity is responsible for the tides on Earth. As the Earth spins, the moon’s gravity causes the tides to bulge towards it creating high and low tides. But the Sun’s gravity also has an effect on the tides so when the Sun and the moon are aligned, the tidal effect is doubled and we get extra high spring tides.
Today, the Sun and moon will align at almost exactly the same time that the moon is at perigee and so the Earth could witness super high tides.
Some people are even predicting earthquakes and tsunamis occurring but we’ll just have to wait and see. When the moon is about half full and at right angles to the Sun, then the Sun and the moon cancel out the tidal effects and we get weaker, neap tides.