Judy Isacoff: Moon, Earth lineup spurs high tides

Friday January 11, 2013

When perigee, perihelion and the new moon coincide, the most exciting place to be is at the sea. Although these astronomical events -- more or less in effect right now -- may not be dramatically felt or seen here in the Berkshires, there’s excitement in wondering about them.

The moon was at perigee -- closest to Earth in its monthly elliptical orbit around our planet -- yesterday morning.

New moon, the lunar phase when the moon is dark, occurs today at 2:44 p.m. Our natural satellite will be at the place in its orbit precisely between Earth and the sun.

The moon is invisible because the sun is lighting the side that is facing away from Earth.

Tides are greatest when the sun, moon and earth are all in a line at new and full moon. The term "syzygy," from the ancient Greek for "yoked together," is applied to this configuration. The extreme tides are called spring tides, not related to the season, rather, from the Old English word "springan," to rise. High tides are highest for the month and low tides are lowest.

Today’s new moon brings not only the highest tides of the month but also of the year because the moon is at perigee and the Earth was recently at perihelion -- nearest to the sun -- on Jan. 2.

Beginning tomorrow, see the crescent moon in its waxing (growing) evening phase, following the sun down.

Contact Judy Isacoff at www.naturesturn.org.


If you'd like to leave a comment (or a tip or a question) about this story with the editors, please email us. We also welcome letters to the editor for publication; you can do that by filling out our letters form and submitting it to the newsroom.

Powered by Creative Circle Media Solutions