Birchat Ha-Chamah

Penina Cohen asks: What exactly is birchat hachamah? What does it signify? How often does it come? What are we supposed to do regarding it?

This question could not be more timely, Penina, because if we don't answer it before erev Pesach, we'll have to wait another 28 years! (And I'm sure blogs will be obsolete by then anyway).


Birchat ha-Chamah is the recitation of the blessing Baruch atah Hashem ....oseh ma'aseh Bereishit (the same bracha that we say when we see lightning). We recite it every 28 years when the vernal equinox (the moment when spring begins) falls out at 6 pm on a Tuesday evening. According to an ancient calculation, this corresponds to the coincidence of astronomical phenomena as they occurred at the moment of the sun's creation on the fourth day (i.e., Tuesday evening). We recite it Wednesday morning (the first time the newly created sun would have risen), which this year is erev Pesach. The astronomy is actually much more complicated than this (and I can't claim to fully understand it myself) but the point of the bracha is to remind humanity that Hashem not only created the world, but continuously upholds the world's existence through His will.

There have been many books and articles about this recently - Rabbi J. David Bleich has updated the one he published in 1981, for example - and consulting them might give you a fuller picture of this rare event.