How did the moon shrink?

Question

The Bavli, Chulin 60:2, says (in my own loose translation):

Rabbi Shim'on ben Pazi noted a contradiction: [B'reshis 1:16] says, "God made the two big luminaries" and "the big luminary… and the small luminary".

The moon said to God: "Master of the world, is it possible for two kings to use one crown?"

He told her: "Go diminish yourself."

She told him: "Master of the world, because I said something proper to you I have to diminish myself?"

He told her: "Go and rule [=shine] by day and night."

(And the conversation continued further.)

Presumably this midrash is not meant literally. (Moons don't talk, for one thing.) But my question will assume it's literal. In other words, my question will be about the storyline of the midrash, assuming its premise.

My question is: In what sense was the moon diminished? Here are the two most reasonable possibilities I can see:

• The sun and moon were the same size (say, a million kilometers' diameter, like the sun is now), and the moon shrank to the 3500 kilometers' diameter it is now.
• The sun and moon were the same apparent size as viewed from earth (same angular diameter) — as they are in fact now! — and the moon shrank in the sense that now it wanes.

Answer 1

I think I remember learning in elementary school that the Moon and the Sun had, as they have now, the same angular diameter when viewed from the Earth, and they also had coronas of equal size, so their total sizes, including coronas, were equal. When the Moon complained about their equality, literally in terms of a "crown" (which a corona resembles and which "corona" literally means), God diminished it by removing its corona.

Answer 2

The explanation referenced in my answer here (I'm still looking for the underlying source - it must be in some maamar or sicha) seems to indicate that the "diminishment" is closer to your second possibility - though focusing not so much on the moon's waxing and waning, but on the fact that it is not self-luminous but receives its light from the sun. (Is there any possible arrangement - perhaps if the moon wasn't tidally locked to earth - in which it could be reflective but not wax and wane, like the planets?)

Answer 3

from here, quoting R. Isaac of Homil (a hebrew biography can be found here):

The moon, when she was first created, was a glistening jewel. She did not merely reflect light, but rather transformed it and brought out its inner beauty, much as a precious stone glistens with a secret, hidden light all its own. In her own way, the moon was greater than the sun -- for the sun only shines from its surface, whereas the moon shone from its inner essence. The sun holds the light that extends outward, whereas the moon holds the light of being.

And so will be, once again, and much more so, in the time to come, once we have transformed the world with the Torah and its mitzvahs. (R. Isaac of Homil, Shnei Me'orot)

The original text for the first paragraph can be found here (towards the bottom of the page).

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Rabbeinu Bechayei, in his commentary on Bamidbar 28:15 (relevant part starts middle of second column), says that the sun and moon were created the same size they are now. The lessening of the moon refers to the lessening of light. Originally they were created giving off equal light, but the moon was subsequently dimmed.

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In a public letter from the Lubavitcher Rebbe (6th Tishre, 5749), the Rebbe says that the lessening of the moon refers to the shorter lunar cycle (11 days less than the solar cycle), which causes the possibility for leap years.

(see also an unedited talk from the Lubavitcher Rebbe (Last day of Pesach, 1984), When Moshiach comes and the moon is restored to its former glory, the lunar and solar cycles will match up, and there will be no need for leap years.)

Answer 4

I would say its luminosity diminished. For most heavenly bodies, the angular size is too small to be resolved by the eye, but the brightness varies by orders of magnitude, so when we say some object is greater or lesser than another, we almost always mean luminosity.

As another option, recall that the Moon was created by a collision of a Mars-sized object with the Earth about 4 Gyr ago. That would be a dimunition in size by a factor of 2 in diameter, and almost 10 in mass.

Answer 5

I heard recently in the name of the Shem Mish'muel (I think the speaker said it's somewhere in sefer Vayikra, but am not sure) that the diminishing of the moon is in that it is sometimes eclipsed.

Answer 6

When the moon was first formed it was much closer to Earth. Over the past 4.5 billion years the moon has been slowly drifting further away, and as a result it would have first appeared 15x larger in the sky than it does today.

Answer 7

To reiterate you question, before looking for the allegorical level of the midrash, what does it mean that Hashem reduced the size of the moon. Your two options are:

1. they were initially identical in size
2. they were identical in size only from the perspective of an Earth observer

To answer, (some of) Chazal believed that the Sun, stars and moon were fixed in the firmament, which seems to be a solid dome. Thus, in Chagiga 12b: רקיע שבו חמה ולבנה כוכבים ומזלות קבועין שנאמר (בראשית א) ויתן אותם אלהים ברקיע השמים

This is of course subject to interpretation. Elsewhere, we see that Chazal subscribed to the scientific belief of the Sun moving in front of the rakia. So offhand, I don't see the possibility of a more distant Sun, such that we are speaking of apparent size.

To properly answer this question, I think an investigation is in order into the contemporary scientific beliefs regarding the relative sizes of sun and moon in the time of Chazal, as well as the Babylonian model which Chazal seem to have adopted. So what I wrote is quite possibly wrong, but is, I think, the proper way to go about answering this question.