March 1, 2020 – Supermoon? Meteor Storm? Hyperbole!

Weather forecasters and services get maligned for an occasional miss.  It was supposed to be mostly clear for our Astronomy Night, but noooo, clouds rolled in just in time to mess with us!  Just saying, weather is still a tricky prediction due to chaotic local conditions.

One thing that meteorologists do predict with dead accuracy is a coming astronomical event.  The event date and time yes.  The event itself, let me say, well…

Take the “Supermoon” event for example.  The term was coined by an astrologer…not and astronomer, and it’s not even and agreed upon condition.  The condition is how close the Full or New Moon is when it’s at perigee (the Moon’s closest approach to Earth for that month).  Perigee varies each month but the Moon’s closest possible approach while orbiting Earth is 221,500 miles/356,500 kilometers.  Most New or Full Moons don’t coincide with the Moon’s closest possible distance or even perigee.  The astrologer Richard Nolle defines a Supermoon as a New or Full Moon within 90% of perigee for that month (actual value varies).  EarthSky uses Nolle’s definition, TimeandDate uses 223,694 miles. Sky and Telescope uses 223,000 miles but refrains to use the term Supermoon.  The preferred scientific term for this is perigee-syzygy, not an attention-grabbing name for sure.  It means the occurrence of three bodies (such as the Earth-Moon-Sun) lined up and one body (the Moon in this case) is closest to its parent body (the Earth).  This line-up can occur either during a full Moon or new Moon, but the new Moon situation is rarely noted.

After all this Supermoon discussion, are they really Super?  Only if you consider a 14% increase in size between the full Moon at apogee (haven’t talked about this, the Moon’s farthest distance from Earth) or what’s termed a Micromoon, and perigee.  Hey, who talks about the Micromoon?  So, a more typical difference would be between usual full Moons and one occurring at or near perigee and that is a less than 14% difference.  IMHO, that’s not super, just a bit bigger.

So, meteorologists, you can call them super, but they aren’t.  I know, whatever!

FYI – the March 9 full Moon is a perigee-syzygy Moon.

Another astronomical event we hear about during weather reports is the meteor shower.  Unfortunately, my opinion sneaks in here to ruin the anticipation.  Yes, meteor showers can be cool, but most are for the meteor shower enthusiast.  I’m not discouraging you from getting out after midnight to look.  I’m just setting expectations.  Most good meteor showers produce one to two visible meteors per minute.  Occasionally we get a treat with several to many meteors per minute, even a bright one called a fireball, or a bolide (a meteor that explodes).  Meteor storms are a rarity and become historic events.

What’s in the Sky?

March 7; after sunset; east:  A nearly full Moon and Regulus are close

March 8; 2 am; Daylight Savings begins