Stand by to see the Supermoon

Tonight the moon will be closer to the earth than it has been for 18 years - a spectacular sight awaits us, says James Attlee.

This weekend a new word rises over the horizon of the English language. The full Moon tonight has been designated a “supermoon” as it will be the nearest approach of the Moon to Earth for the past 18 years, bringing it some 30,000 miles closer than usual. If we have clear skies, this lunar event will be weighted with a special sense of expectation – perhaps, for some people, even dread.

The astrologer who named it a “supermoon” predicted that its arrival would coincide with chaos on Earth, and points to the earthquakes in New Zealand and Japan as evidence. The Moon’s closeness this weekend means that its usual gravitational pull on our tides will be intensified; we can expect high tides in two days. The oceans are not the only things that respond to the Moon’s approach; the Earth’s crust is not solid, but expands and contracts to a small degree in response to the Moon’s attraction, a phenomenon known as “earth tide”; a small increase in such tectonic shifts might be expected.

Those planning to watch it should be in position as the Moon rises above the horizon, at between 6.15 and 6.45pm, depending on your location; this is when the Moon looks largest, owing to the well-known “moon illusion”. (This is often thought to be caused by the fact that on the horizon, the Moon is close to objects with which we can compare it, making it seem very large, while when it is overhead it is in isolation, so that the brain reads it as smaller.) Even though the fact that the Moon is closer than usual will not make it seem any bigger, the illusion will guarantee that its ascent is suitably dramatic.

The size of the Moon as it rises may not be the only thing that is illusory. If scientists have failed to discover any data supporting a causal linkage between the fullness or nearness of the Moon and geothermal or seismic activity, the currency given to such claims is, at least, a vivid demonstration of the grip the Moon still has on the human mind. When did the Moon begin to exert this gravitational pull upon our collective imagination?

Lunar deities feature in many of the world’s first recorded religions. At a subconscious level, the lunar cycle acts as a time-trigger for the reproductive activities of many living species. Certain corals spawn triggered by the full moon; fish rise to the surface to breed summoned by its light and new research suggests that a link between women’s fertility and the lunar cycle may not be mere folklore after all. But it is the light the Moon casts that has particularly fascinated artists down the centuries, a light that is circumscribed in increasingly large areas of our country by ever present, 24 hour illumination.