Q&A: Mayim Shelanu: The Sun No Longer Travels at Night Beneath the Rivers…
Mayim Shelanu: The Sun No Longer Travels at Night Beneath the Rivers…
Question
The sun does not travel at night beneath the rivers.
Do we still need “mayim shelanu”?
Answer
The question of why the water warms up during the day is not relevant. The fact is true (that water warms up during the day and in the morning it is colder). Therefore this Jewish law still stands. Of course, one can cool the water in the refrigerator, and then the problem does not exist.
But there still remains the question whether this is an enactment that must be kept even if its rationale no longer applies. In Mikra’ei Kodesh 2:7, he cites halakhic authorities who wrote that even in hot countries, where letting the water sit may not cool it sufficiently, one should still let it sit. I am not sure he is right, since it is possible that the enactment is that the water should be cold, and not specifically that it must sit overnight.
Discussion on Answer
Correction.
That they should draw it.
Moon, it seems to me that water in large reservoirs loses the heat absorbed during the day more slowly than water in a jug, because the ratio of volume to surface area is greater.
If you take a cupful from the sea at sunset and measure the temperature of the water in it an hour later, it will be lower than the temperature of the seawater at that same time.
Water has a higher heat capacity (how much heat (energy) must be added to a kilogram of water in order to raise its temperature by one degree) than soil. That is why the water in the sea is warmer than the ground at night (and colder in the morning).
So Lev and Emanuel agree that it would be preferable to draw it in the morning and not in the evening before sunset…
If so, why do they draw it toward evening?
I don’t know
If so, then let them draw it in the morning.
What’s the point of drawing it an hour before nightfall, when the water is at its warmest?
On the contrary, they should draw it in the morning or toward dawn, when it is coldest…