The ‘Splainer (as in “You’ve got some ‘splaining to do”) is an occasional online feature in which Kimberly Winston and other RNS staff give you everything you need to know about current events to hold your own at a cocktail party.

(RNS) Sheryl Sandberg's essay on grieving, written this week after she emerged from the 30-day Jewish mourning period known as "shloshim," has gone viral. People worldwide have admired the Facebook COO's candor in the wake of the sudden death of her 47-year-old husband, Dave Goldberg. But what happens during shloshim that made Sandberg begin her piece: "I have lived thirty years in these thirty days. I am thirty years sadder. I feel like I am thirty years wiser"?

Q: Shloshim? Never heard of it.

A: Shloshim is the Hebrew word for "30." Jewish law prescribes different mourning periods, each with its own set of practices. "Shiva" is the intense seven-day mourning period just after a burial, in which mourners stay at home and receive condolence calls. Shloshim includes shiva and is the monthlong period after a burial. During the part of shloshim after shiva, mourners resume some of their normal activities, such as going to work.

Q: Do all Jews do this?

A: Orthodox and some Conservative Jews will abide by a long list of prohibitions during shiva and shloshim, and in some cases, during the first year after a death. Observant Jews may not listen to music or cut their hair during shloshim, for example. Many less observant Jews "sit shiva," but then forgo shloshim.

Q: What's the logic behind all these distinct periods of mourning?

A: Rabbi Jonah Pesner, who heads the Religious Action Center of Reform Judaism, compares them to his father's teaching him how to swim. "At first, I knew his hands were still there and I would test to make sure; ultimately I swam away and was on my own. He died when I was still a teen, not many years after he taught me to swim."

Sandberg's piece, he said, reminded him about "how Jewish mourning customs and the Jewish community hold us, guide us -- and finally as they let go, enable us to let go as well."

Q: So how did this mourning ritual transform Sheryl Sandberg?

A: Jewish mourning rituals do a good job of providing time and space for grief, said Rabbi Joshua Lesser, who heads Bet Haverim, a progressive Atlanta congregation where the laws of mourning can serve more as guideposts than requirements.

"The recognition of loss and the invitation to community to share some of the burden of that loss -- as well as the excused withdrawal from other activities -- often provides relief, restoration and the permission to experience the range of emotions that a loss of a loved one can exact," he said.

Q: There's something important called Kaddish, right?

A: Kaddish, which means "holy" in Aramaic, is a 2,000-year-old prayer praising God. Jewish law requires that it be said daily during the mourning period. Because it is only to be uttered in the presence of a minyan -- a minimum of 10 Jews -- some have noted that the requirement draws mourners into the company of others.

YS/MG END MARKOE