Hours, minutes, and chalakim

Question

On Shabbat preceding Rosh Chodesh, the time of the molad is generally announced in units of hours, minutes, and chalakim. However, minutes are not a traditional Jewish unit of time; rather hours are divided directly into 1080 chalakim. So why don't we just announce the molad in units of hours and chalakim? On the other hand, if the goal is to make it easier for people familiar with our modern time system to understand the time of the molad, why don't we go all the way and convert the chalakim into seconds. (One chelek easily converts to 3 1/3 seconds.)

So for example, the molad for Kislev 5771 could be announced as "4 minutes and 10 seconds after 9pm on Motzei Shabbat" rather than "4 minutes and 3 chalakim after 9pm".

Answer 1

Regarding converting Chalakim into seconds, that would only work on the months that it is 3,6,9,12, or 15 Chalakim. However imagine next month Teves when the Molad is Monday 9:48AM + 4 Chalakim, would you announce Monday 48 minutes and 13 1/3 seconds after 9AM?

If you would announce just the hours and Chalakim most people would have no idea what you are talking about and even if they knew would be confused. Imagine next month Teves announcing the Molad is Monday at 9AM + 868 Chalakim. Most people in the Shul would have no idea or would need their calculators to start figuring.

So I guess it is done this way for practical reasons.

Answer 2

Perhaps announcing the molad in thirds of seconds would give the misleading impression that the molad is precise to thirds of seconds. For example, announcing that the molad is 3 1/3 seconds after 9:00pm might give the impression that the molad was calculated to be closer to 3 1/3 seconds after 9 than it is to 3 seconds after 9. By giving the molad in chalakim, it is that the precision of the molad is only to the nearest chelek.

However, I don't fully accept this explanation, because for the halakhic purpose of laying out the calendar, the molad is exact, so precision seems irrelevant. And from the scientific perspective, while the interval between moladot accurately approximates the average time between lunar conjunctions to within a fraction of a chelek, over time the error has certainly accumulated to more than a chelek.

Answer 3

I have heard it announced in minutes and chalakim and then also in minutes and seconds, but, no, that's not the norm (in my experience).

Answer 4

How many people are really calculating the time to say qiddush levanah down to the minute anyway? The day, or time of day, should be sufficient. The chalaqim merely add a traditional flavor and historical precision to the molad moment, which is reported in our familiar international time scheme of hours and minutes.

We also tend to announce it in the vernacular, even though the days of Rosh Chodesh themselves-- much more important to every individual's ritual calculations-- are usually left to the liturgical Hebrew and personal calendars.

On some months one could avoid the minutes anyway, and report only chalaqim, if the time is close enough to the hour, e.g. the molad for this coming Iyyar (5776) is 59 minutes & 17 chalaqim after 10pm, but both of those amounts are just one increment shy of their unit limit; the same moment could be expressed more simply as 1 cheileq to 11.

However, the opposite possibility is more likely to be manifest in the current system-- with an even number of minutes, but no chalaqim-- because that occurs every year and a half according to our formula, whereas it will take about 75 years until we get to the next even hour without minutes or chalaqim attached.