Did You See the Full Moon Tonight?

From EarthSky:


According to U.S. clocks, May 5, 2012 features the closest and largest full moon of this year. Calendars say May 6, by the way, for this same close full moon as seen from Europe, the Middle East, Africa and Asia. We astronomers call this sort of close full moon a perigee full moon. The word perigee describes the moon’s closest point to Earth for a given month.

The supermoon of March 19, 2011 (right), compared to an average moon of December 20, 2010 (left).

Will you be able to notice with your eye alone that tonight's full moon is bigger or brighter than usual?

Astronomers say no, but it'll be fun to stand outside under tonight's full moon and know

the moon is closer than it has been since March 19, 2011.

Image Credit: Marco Langbroek, the Netherlands, via Wikimedia Commons.

The 2012 May full moon falls some six minutes after perigee, the moon’s closest point to Earth for this month. At perigee, the moon lies only 356,955 kilometers (221,802 miles) away. Later this month, on May 19, the moon will swing out to apogee – its farthest point for the month – at 406,448 kilometers (252,555 miles) distant. So you can see tonight’s moon really is at its closest.

In fact, May 2012 presents the moon’s closest encounter with Earth since March 19, 2011, at which time the moon was a scant 380 kilometers closer to Earth. The moon won’t come as close as tonight’s extra-close moon until August 10, 2014 – although in 2013 the moon at its closest (June 23, 2013) will lie only 36 kilometers farther away than the closest moon in 2012. (See table below) Maybe this helps you see that supermoons – while interesting – are fairly routine astronomical events.

Even the proximity of full moon with perigee in today’s moon isn’t all that rare. The extra-close moon in all of these years – 2011, 2012, 2013, 2014 and 2015 – finds the full moon taking place within an hour or so of lunar perigee. More often than not, the closest perigee of the year comes on the day that the full moon and perigee coincide.

By the way, according to U.S. clocks, the full moon falls this evening at precisely at 10:35 p.m. Central Daylight Time. This same full moon falls tomorrow (Sunday, May 6) at 3:35 Universal Time (UT) – the standard time at the prime meridian of 0^o longitude, or, for example, in Greenwich, England.

Will the tides be higher than usual? Yes, all full moons bring higher-than-usual tides, and perigee full moons bring the highest (and lowest) tides of all. Each month, on the day of the full moon, the moon, Earth and sun are aligned, with Earth in between. This line up creates wide-ranging tides, known as spring tides. High spring tides climb up especially high, and on the same day low tides plunge especially low.

The "supermoon" over our place a few minutes ago.

But will it make the fish bite?