The Solar Eclipse

Friday March 20 - An Astronomic Trifecta, +1

Tomorrow, Friday March 20, 2015, is a very important day for astronomers. That's because three events will coincide: the Spring (Vernal) equinox, a super-moon (in which either a full moon or a new moon occurs during the moon's closest approach to Earth) and...a solar eclipse. (And then of course on Friday night it is ראש הודש ניסן – the start of the month of Nissan.) We will discuss the eclipse, which unfortunately will only be visible over north Africa, Israel and most of Europe, as you can see in the animation. (For those in North America, there will be nothing to see, since the eclipse will occur during the night.  If you live there, the next solar eclipse will be on August 21, 2017.  You may stop reading this, and return to this page in two and-a-half years.)

In Israel, and over most of Europe, this solar eclipse will be partial, with the moon taking only a little bite out of the sun's disc. (To experience a full solar eclipse you'll need to be somewhere in the north Atlantic or on Denmarks's Faroe Islands, which are about 200 miles northwest of Scotland.) In Jerusalem the eclipse will begin at 11:16am.  At its maximum (11:58am)  there won't be any noticeable darkening, but if the sky is clear, you'll see something like this:

Screen Shot 2015-03-18 at 10.17.18 AM.png

The Talmud on Eclipses

תלמוד בבלי סוכה דף כט עמוד א 

תנו רבנן: בזמן שהחמה לוקה - סימן רע לעובדי כוכבים, לבנה לוקה - סימן רע לשונאיהם של ישראל, מפני שישראל מונין ללבנה ועובדי כוכבים לחמה...

תנו רבנן: בשביל ארבעה דברים חמה לוקה: על אב בית דין שמת ואינו נספד כהלכה, ועל נערה המאורסה שצעקה בעיר ואין מושיע לה, ועל משכב זכור, ועל שני אחין שנשפך דמן כאחד

Our Rabbis taught, A solar eclipse is a bad omen for idolaters; a lunar eclipse is a bad omen for Israel, because Israel reckons [its calendar] by the moon, and idolaters by the sun...

Our Rabbis taught, A solar eclipse happens because of four things:
1. When an Av Bet Din [head of the Rabbinic Court] died and was not properly eulogized;
2. If a betrothed girl cried out aloud in the city and there was no-one to save her [from being raped];
3. Because of homosexuality; and
4 If two brothers were killed at the same time.
— Sukkah 29a

That's what we have - four causes of a solar eclipse.  And how does Rashi explain this passage?       לא שמעתי טעם בדבר  - "I have not heard any explanation for this." 

The Real Cause of a Solar Eclipse

Courtesy of NASA

Courtesy of NASA

 A solar eclipse occurs when the moon gets in-between the sun and the earth. When it does, it casts a shadow on the earth, and if you fall in that shadow (called the umbra), you see an eclipse.  That's it. Simple. Nothing to do with rape. Or homosexuality. Or murder. But on every Rosh Chodesh, the moon is exactly between the sun and the earth - so why don't we see a solar eclipse every month? The answer is also simple. The moon's orbit is inclined at 5 degrees from the sun-earth plane, so that each month the moon may be slightly above, or slightly below that plane. And an eclipse will occur only when the three bodies line up on the same plane.  


Later Jewish Explanations of a Solar Eclipse

If we know that eclipses are regular celestial events whose timing is predictable and precise, how are we to understand Talmud in Sukkah, which suggests that an eclipse is a divine response to human conduct? We have already seen that Rashi was unable to explain the passage, but that didn't stop others from trying.  The Maharal of Prague (d. 1609) has a lengthy explanation which you can read here.  It goes something like this: "Yes, an eclipse is a mechanical and predictable event. But in truth, if there was no sin, there would be no eclipses, because God would have designed the universe differently, and in such a sin-free universe...there would be no need to design an eclipse." So the Maharal suggests that in a sin-free universe, the moon would not orbit as it does now, at a 5 degree angle to the sun-earth plane.  But where would the moon be? It couldn't be in the same plane as the sun and the earth, since then there would be a solar eclipse every month. If it were at say 20 degrees above the plane, then there would still be solar eclipses, though they would be more rare. The only way for there to be no solar eclipses (in the Maharal's sin-free imaginary universe) would be for the moon to orbit the earth at 90 degrees to the sun-earth axis.  Then it would never come between the sun and the earth, and there could never be a solar eclipse. Perfect, except then there would never be a Rosh Chodesh, and the moon would always be visible. Oy.

יערות דבש, דרוש י’ב

יערות דבש, דרוש י’ב

Another attempt to explain the Talmud was offered by Jonatan Eybeschutz (d. 1764). In 1751 Eybeschutz was elected as chief rabbi of the Three Communities (Altona, Hamburg, and Wandsbek), and was later accused of being a secret follower of the false messiah Shabtai Zevi. In January 1751, Eybeschutz gave a drasha in Hamburg in which he addressed the very same problem that Maharal had noted: if a solar eclipse is a predictable event, how can it be related to human conduct? His answer was quite different: The Talmud in Sukkah is not actually addressing the phenomenon that we call a solar eclipse. According to Eybeschutz, the phrase in Sukkah "בזמן שהחמה לוקה" actually means - "when there are sunspots."

Inventive though this is, it is as implausible as the suggestion of the Maharal. In the first place, sunspots were almost (but not quite impossible) to see prior to the invention of the telescope. They were described in March 1611 by a contemporary of Galileo named Christopher Scheiner (though Galileo lost no-time in claiming that he, not Scheiner was the first to correctly interpret what they were.)  Because sunspots were so difficult to see with the naked eye, it seems unlikely that this is what the rabbis in Gemara Sukkah were describing.

Christopher Scheiner, Rosa Ursina sive Sol           (Bracciai 1626-1630)

Christopher Scheiner, Rosa Ursina sive Sol           (Bracciai 1626-1630)

Second, according to Eybeschutz, sunspots "have no known cause, and have no fixed period to their appearance".  We can't fault Eybeschutz  for his first claim, but - even by the science of his day - his second was not correct. In fact both Scheiner and Galileo knew  - and wrote - that sunspots were permanent (at least for a while) and moved slowly across the face of the sun.

Sidebar: Eybeschutz, Sunspots and Copernicus

It's interesting to note that Galileo got very excited about the discovery that the spots moved across the face of the sun. This suggested (though it did not prove) that the sun itself was spinning. Galileo had also discovered that Jupiter was orbited by moons. Both of these discoveries now added further support to the Copernican model in which the Earth was spinning on its own axis, and was not the center of all the movement of objects in the sky. But Eybeschutz did not believe Copernicus was correct: "Copernicus and his supporters have made fools of themselves when they declare that the Earth orbits [the Sun]. They have left us with a lie, and the truth will bear itself witness that the Earth stands still for ever."  Eybeschutz wanted to have sunspots explain away a talmudic mystery, but he dismissed the evidence that they provided in other matters - namely, that the earth moves.  

Was the Plague of Darkness a Solar Eclipse? 

Since we are only a couple of weeks before פסח, we will end with another look at an old theory, in which the Plague of Darkness was caused not by a miracle, but rather by a (conveniently timed) solar eclipse.  In 1916 Eduard Mahler (d. 1945)  suggested this explanation in his Handbuch der Jüdischen Chronologie, (Vienna 1887).  According to Mahler, there was a solar eclipse visible in Egypt on Thursday March 13, 1335 BC. Since this was the only such eclipse, it would date the Exodus as occurring on March 27th, 1335 BC.

However, there's an obvious problem: the Torah describes the darkness lasting for three days. But a solar eclipse is over in a matter of minutes.  Mahler has in interesting answer: instead of reading the verses (in Exod. 10) like this:

(22) there was a thick darkness in all the land of Egypt for three days. (23) They did not see each other, or get up from their places for three days.

read them like this:

(22)  there was a thick darkness in all the land of Egypt. (23) For three days they did not see each other, or get up from their places for three days.

The eclipse lasted only a few minutes, but its effect on the Egyptians lasted three days. And what about the Jews in Goshen -why was there no Plague of Darkness there? Because they lived outside of the totality -  the area in which the complete eclipse occurred -  and would not have noted any significant darkening. Now there are some problems with this theory - like the fact that according to NASA, the solar eclipse to which Mahler referred seems to have been only a partial eclipse throughout Egypt. Still, it makes for a good discussion. Try that at your Seder Table.