Courtesy - The Nation By Carol AloysiusAstronomers and astrologers alike eagerly scanned the night skies yesterday, to gaze their full on a very rare and beautiful sight: A full Moon of rare size and beauty which rose in the Eastern skies at sunset.
“It’s a super ‘perigee Moon’ – the biggest in 18 years. The last full Moon so big and close to Earth occurred in March of 1993,” said Geoff Chester of the US Naval Observatory in Washington DC, obviously excited by the rare phenomenon that unfolded in the skies.
Full Moons vary in size because of the oval shape of the Moon’s orbit. It is an ellipse with one side (perigee) about 50,000 km closer to Earth than the other (apogee) – see the diagram. Nearby perigee Moons are about 14% bigger and 30% brighter than lesser Moons that occur on the apogee side of the Moon’s orbit.
“The full Moon of March 19 occurred less than one hour away from perigee – a near-perfect coincidence that happens once in only 18 years or so,” added Chester.
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A perigee full Moon brings with it extra-high “perigean tides,” but this is nothing to worry about, according to him. In most places, lunar gravity at perigee pulls tide waters only a few centimetres (an inch or so) higher than usual. Local geography can amplify the effect to about 15 centimetres (six inches) – not exactly a great flood.
Indeed, contrary to some reports circulating the internet, perigee Moons do not trigger natural disasters. The ‘supermoon’ of March 1993, for instance, passed without incident. And an almost-super Moon in December 2008 also proved harmless, NASA sources believe.
The best time to look is when the Moon is near the horizon, they say. “That is when illusion mixes with reality to produce a truly stunning view. For reasons not fully understood by astronomers or psychologists, low-hanging Moons look unnaturally large when they beam through trees, buildings and other foreground objects. So, on March 19, when the swollen orb rose in the East at sunset, it seemed so nearby, you could almost reach out and touch it.
So what did our local astronomers have to say on yesterday’s spectacular sky show?
Janaka Adassuriya, a Researcher from the Arthur C Clarke Institute at Moratuwa told The Nation, “Yesterday, the full Moon was 14 percent bigger than usual full Moon that we see. That occasion was rare as the Moon appeared in its biggest in 18 years. NASA said it was a super “perigee moon.”
“The Moon revolves around the Earth in an elliptical orbit. The longest point from the Earth to the Moon in this orbit is called the apogee while the shortest pint is called the perigee. In a lunar month the Moon completes one orbit and passes these two points. The full Moon can occur in any point on this orbit. But the occurrence of the full Moon in the perigee is very rare. Once the full Moon occurs in the perigee it will be the closest full Moon seen by the Earth,” he explained.
The previous super Moon in 1993 and 1983 passed without any incident. Some people believe there is a possibility to occur natural disasters with this event. But there is no solid evidence that the super Moon triggers natural disasters.
