Overstated in orbit
See Neil Armstrong recall his Apollo 11 days.
I DON'T believe Neil Armstrong ever used the term ''super moon'', let alone the freshly minted ''extreme super moon''. The reason is the terms have been coined recently by non-astronomers to capture headlines, and I don't know of one astronomer who has ever used those terms to explain anything. It's a cheap publicity trick - come up with a new phrase for the same old thing and add superlatives to attract attention.
The reason for mentioning this is that these terms are likely to hit the news this weekend by those prophesying catastrophes such as earthquakes, tsunamis and new Justin Bieber CDs. The traditional term astronomers invoke for such lunar phenomena is ''perigee'', meaning the closest point to Earth reached by the moon in its orbit. Such a position is reached once every month but the distance varies because the moon's orbit is elliptical and also ''orbits''. Using the centres of both the moon and Earth for the measurement, when the moon rises on Sunday at sunset, it will be about 357,000 kilometres away. Unusually, it will coincide with a full moon.
In case you're thinking that the two together spells doom for Earth, please don't be alarmed. First, the fact the moon will be full is irrelevant. Perigee brings the mass/gravity of the moon closer and that's what naysayers will attribute to earthquakes and tsunamis. With this in mind, I've done a survey of the 10 earthquakes with largest magnitudes in the past 400 years, and not one of them occurred when the moon was closest to Earth for that year.
However, the moon will look almost 10 per cent bigger when compared with a full moon occurring at ''apogee'' - the furthest point from Earth - and will be well worth a look.
Even more riveting this week, Armstrong began a rare interview series about his recollections of the greatest adventure of mankind.
He has shunned the spotlight since the Apollo 11 days and I can't recall any in-depth video interview of him. This world-premiere internet-only series is presented by CPA Australia, with the second instalment available on May 8. An Audience with Neil Armstrong can be seen at cpaaustralia.com.au/ thebottomline and it promises to be a must-see, in which nobody will use a phrase such as ''ultra-premium extreme super moon''!
Follow Perry Vlahos on Twitter @Perryastronomy