A full Moon rises over the Cascade Mountains in this image taken in the US state of Washington in 2005. On 12 December, the full Moon will be just 356,567 km from Earth. On average, it lies 384,400 km away (Image copyright 2005 David Haworth) The difference in the full Moon’s size at its farthest (apogee) and closest (perigee) points from Earth is hard to distinguish by eye, but it is noticeable in these side-by-side images taken in 2004 (Image: Anthony Ayiomamitis)

The full Moon will loom larger in the sky on Friday than it has since 1993, as it will be nearly as close as it ever comes to Earth in its orbit.

The Moon does not orbit Earth in a perfect circle. Instead, it follows an elliptical path that brings it 50,000 kilometres closer to our planet on one side of its orbit (called perigee) than the other (apogee).


On 12 December, the Moon will enter its full phase, when its disc appears completely illuminated by the Sun, just four hours after reaching its closest point to Earth. This will make it 14% bigger and 30% brighter than other full Moons in 2008, though the difference will be hard to distinguish by eye (see the difference in the full Moon’s size in 2004).

It will be eight years before the Moon appears so big again. “This evening’s Moon is not only the largest for 2008 but also during the period 1993-2016,” says Anthony Ayiomamitis, who lives in Greece.

For observers in the northern hemisphere, tonight’s full Moon will also appear higher in the sky than any other this year. Around midnight, it will shine down from nearly overhead.