A Scratch on the Wall

According to the Midrashim quoted by Rashi, Yitzchak was born precisely a year after the angels visited Avraham and Sarah, on the first day of Pesach. (According to the gemara Rosh HaShanah 11a the angels visited on Sukkos.) Rashi (21:2) writes that HaShem gave Avraham a sign. On the day the angels visited, HaShem made an etching in a wall and told Avraham, "When the sun reaches this point again next year, you will have a son." This sign requires some clarification. How exactly did this work?

An object that is standing upright in the path of the sun will form a shadow on the ground. The exact direction of the shadow depends on the position of the sun in the sky. As the sun moves through the eastern sky in the first half of the day, the shadow will be pointing westward and vice versa for the second half of the day. However, the exact direction of the shadow, i.e., its northerly or southerly bearing, will constantly change. As well, the size of the shadow is dependent on the north/south position of the sun as well. These are the principals behind the sundial. All of the factors change throughout the day and the daily patterns change throughout the year as a result of the change in direction of the earth's tilt. However, one thing is certain. At midday, the sun is not in the eastern sky or the western sky. Rather, it is either due north or due south, depending on where you are in the world. What is relevant to us is that since Eretz Yisroel, at approximately 31^o North, is above the Tropic of Cancer (23.5^o North), the sun will always be in the southern sky at midday. The size of the shadow depends on the angle of the sun in the sky which depends directly on the time of year.

Any sign involving a shadow would surely have been simplest to arrange at midday. It is therefore most noteworthy that the gemara (.ברכות כ"ז) infers from the words (18:2) "kechom hayom," in the heat of the day, that the angels visited in the sixth hour. After the food was prepared and served and the angels conversed with Avraham, it seems altogether plausible that it was exactly midday. It seems that the sign that was given was that at that moment, the southern wall (or other standing object) was casting a shadow on the northern wall. The scratch that was made on the wall indicated the end of the shadow. When the shadow reached the exact same point at midday sometime in the next year, it would indicate that a complete year had passed.

With all this considered the Midrash is quite troubling. All these details are specific to the solar year. However, Yitzchak was born precisely one year later by the lunar calendar, not the solar calendar. What significance could any sun-related sign have to the passing of a lunar year?

I particularly enjoyed the answer that Pi offered in the comments:

On pasuk 18:10, Seforno says: שוב אשוב אליך - למועד המילה כפעם בפעם.‏ This suggests that the time the angels would return a (solar) year later was not the exact day of Yitzchak's birth, but rather some time later. The book קונטרס די שמיא by Alexander Shutz on pages 18-19 claims that the ריב"א asks your question, and that ר' צבי יודא פריידמאן suggests the following answer: The angel Rephael would come back three days after Yitzchak's bris mila to heal him, which would be (about) 11 days after his birth, so that could have been the occasion when the sun reached the line that was marked on the wall.

Witnesses to Sedom's Destruction

Rashi on 19:24 notes that the destruction of Sedom happened at day break, when the sun and moon were in the sky at the same time. This was because they used to worship the sun and moon. HaShem therefore brought the destruction when both were out as a proof to all the sun and moon worshipers that the sun and moon are powerless. Had the destruction taken place when they were not in the sky, one could have argued that they were not "there" to save them. This is a rather simple statement by Rashi but the astronomical basis for it is quite interesting.

 

It is not always that the sun and moon are out together at day break. It is also not always that it is the only time that they are out together. The moon rises and sets approximately 49 minutes later each day. This is a result of the moon orbiting the earth. Just as the moon's position is reset at the end of every month, so are its rising and setting times. (The math is as follows: Every full moon cycle (month), moonrise and moonset make a full circle of 24 hours such that the times are as they were precisely one month previous. The figure of 49 minutes is achieved by dividing 24 hours by the duration of the lunar cycle, 29.5 days, 44 minutes, 3 and a third seconds. More precisely, the figure is 48 minutes, 45.5 seconds.)

At the beginning of the month, the moon follows a very similar schedule to the sun. The moon rises at the beginning of the day and sets at sundown. As the month progresses, the moon rises and sets later and later. At the middle of the month, the moon has virtually the opposite schedule to the sun. It rises when the sun sets and sets when the sun rises. As we enter the second half of the month, the moon begins to rise later in the night and thus, becomes visible at the beginning of the day.

The Midrash (Bereishis Rabba 50) teaches that Sedom was destroyed on the 16th of Nissan. As explained above, at that time of the month, the moon would have risen shortly after sunset and set very shortly after sunrise. Therefore, the only time in the entire day that both the sun and moon were out at the same time was very early in the morning and that is why the destruction took place specifically at the very beginning of the day. [Nevertheless, it is puzzling that Rashi uses the term "Alos HaShachar" which refers to a time before sunrise.]

The Mysterious Midrash

The parsha begins with Avraham Avinu sitting at the doorway of his tent awaiting the opportunity to invite guests in for a meal and, perhaps, teach them of Hashem's ways. The Torah tells us that Avraham was sitting there in the heat of the day. (Bereishis 18:1) Rashi cites from a Midrash that Hashem took the sun out of its shield in order for its rays to be more powerful. Thus, the day was unnaturally hot. Since the pasuk says that it was in the heat of the day, it must mean that it was an unnatural heat. What exactly could this Midrash be referring to when it mentions that the sun was taken out of its shield? Also, why are we to assume that the wording of, "in the heat of the day," means an unnatural heat, maybe it just means during the hottest part of the day?

By analyzing a perplexing passage from Rabbeinu Bacheye's commentary to this portion one can, perhaps, gain better insight. Rabbeinu Bacheye cites a Midrash that Avraham was sitting at the doorway at the fourth hour of the day. This is the a time when, historically, people would be hungry and looking for a meal. Therefore, Avraham wished to capitalize on this opportunity to find a wayfarer in need of a meal and invite him in. It is unclear what Midrash Rabbeinu Bacheye is citing from because we do not seem to have anything that expresses this point. Additionally, this Midrash appears to be in conflict with the Gemara in Berachos (27a) that seems to state that Avraham was sitting there at midday. Why would Rabbeinu Bacheye choose to convey the message of an obscure Midrash as opposed to the Gemara's interpretation?

The Gemara cited above is trying to determine how much of the day can be considered morning. At one point it cites a verse that states that when the sun is hot it will melt the manna and this is applied to the beginning of the fourth hour. The Gemara challenges this by asking that perhaps it means until midday since the sun continues to heat up until that point. To this the Gemara cites the pasuk from our parsha and says that since our pasuk is referring to midday, the pasuk referring to the sun's heat must mean until the fourth hour. Rashi explains that the pasuk from our parsha mentions that the day is hot as opposed to the other pasuk which mentions that the sun is hot. The implications of our pasuk are that it is not just the areas in direct sunlight that are hot, but even areas that are normally shady are hot since the pasuk says, "the heat of the day," and not, "the heat of the sun." Once we find that the Torah uses two forms of expression when referring to the heating of the sun and day, the Gemara concludes that the two must be referring to different times of the day. The one mentioning when the sun is hot is not as hot as the one that mentions that the day is hot.

Perhaps, the above understanding can help answer all the above questions. The normal implications of the wording of our pasuk indicate a time when even shady areas are hot and this is midday because the sun is high in the sky and the actual shadows are relatively small. This leaves a significant area that is normally covered in shade to be exposed to the heat of the sun. This time is called in the "heat of the day." Since this language is conveying this message, the other pasuk cited in Berachos refers to the fourth hour which is when the sunny areas begin to feel hot, thus it is called, "the sun's heat." It is important to note that it is irrelevant to the Gemara whether or not the time period discussed in the pasuk in our parsha was actually midday. The Gemara is just proving that it is referring to a time when both sunny and shady areas are hot. This would normally occur at midday and that means that the other pasuk must refer to the fourth hour. However, since Hashem took the sun out of its shield it is possible that the phenomenon of shady areas being hot actually happened earlier and it just felt like midday. The Torah is just letting us know where the sun was positioned and not how many hours of the day had passed.

Rabbainu Bacheye's Midrash provides the logic upon which it is based. Avraham would sit in the doorway at the most opportune time. Since people are hungry at the fourth hour, it stands to reason that this event happened at that time. If so, how could it be that the pasuk uses language to tell us that the heat was equal to that of midday, the pasuk should have stated that the sun was hot since this is less extreme? This would seem to be where the Midrash that Rashi cites starts from. It must be that Hashem took the sun out of its shield, meaning that he raised it higher in the sky so that the rays were more direct and there were fewer shadows. The heat was comparable to midday, but the actual time was only the fourth hour. Thus, Rabbeinu Bacheye, the Midrash cited by Rashi, and the Gemara all complement each other as opposed to contradict one another. I apologize if this was confusing, this is not normally the style in which these posts are written. I just found it pretty amazing that the elusive identity of the Midrash of Rabbeinu Bacheye might actually be a Midrash that was in plain sight!!!

Lot's Twilight Escape

There is a dispute in the Gemara as to the length of halachic twilight in the morning hours. One opinion mentions that this is a 4 mil time interval and the other states 5. As a proof to the opinion of 5 the Gemara cites from this week's parsha when Lot was escorted out of Sedom in the early hours of the morning. The Gemara maintains that he traversed a 5 mil distance in the exact amount of time between dawn and sunrise. (See Pesachim 93b)

Although this proof is ultimately rejected because it seems that Lot was rushing and the Gemara is referring to people traveling at an average pace, it seems that barring this point that the Gemara would have been content with this proof. The question one may ask is that twilight periods vary based on latitude and also based on the time of the year. How did the Gemara know that the case of Lot was a good proof, perhaps, it happened in a location other than the one the Gemara was discussing, or at a time of year different from the one in the Gemara?

The Gemara's discussion was regarding Korbon Pesach, so we can deduce that the location of its discussion is in Eretz Yisrael. We can also deduce that the time of year it was discussing was at the beginning of spring since that is when Pesach falls. How did the Gemara know that Lot's escape was at this time and location?

Regarding the location, the Gemara easily knew that Lot's escape was in Eretz Yisrael because it happened in Sedom. The Gemara also seems to be of the opinion of the Bereishis Rabbah regarding the time of Lot's escape. Bereishis Rabbah maintains that it happened on the second day of Pesach. (Bereishis Rabbah 48:12) In fact, Rashi also mentions the fact that it was on Pesach. (Rashi Bereishis 19:3) So, with these facts being presented one can clearly see that had it not been for the fact that Lot was running for his life, the Gemara would have had an adequate proof.

I Can't Believe Its Not Fresh

In the beginning of the Parsha we see that Avraham Avinu went to tremendous lengths in order to prepare feasts for the passersby that were lucky enough to be his guests. During the feast that he served the three angels that visited him after his bris, he had Sarah Imeinu make bread from three se'ah of fine flour, he had three oxen slaughtered to serve three separate tongues with mustard, and he had butter and milk brought to them. We see clearly how dedicated Avraham was in his hachnasas orchim. (See Bereishis 18 and Rashi's commentary.)

It is interesting to see that Avraham did not seem to have anything prepared for these wayfarers. We are taught that Avraham epitomized kindness. One would have thought that he would have had food prepared for the occasional guest that might accept an invitation. Nevertheless, in this week's storyline we see that Avraham clearly asked the visitors to rest for a bit while he went to prepare their food. Why would Avraham risk losing these guests by not having food ready for their possible arrival? The answer is simple, Avraham wanted evrything to be fresh. What sojourner could pass up a fresh meal filled with the choicest foods? Avraham knew that he would not lose guests if he asked them to relax while he prepared them a meal that was fit for a king. Therefore, he purposefully did not have food ready for their arrival. Additionally, while they rested Avraham would have ample time to strike up a conversation with them and teach them about Hashem.

It is so interesting to note that Avraham clearly wanted everything to be fresh so that he could serve his guests the finest delicacies. The meat was freshly slaughtered and the bread was freshly baked. Why then was the milk and butter only brought to the meal and not milked and churned that day? (See Bereishis 18:8) Perhaps, the answer lies in the date of this monumental feast, Pesach. (Rashi, Bereishis 18:10) It is prohibited to milk animals in order to drink their milk on Yom Tov, and it is also prohibited to churn butter on Yom Tov. (Shulchan Aruch Orach Chaim 505:1; and Rema 510:5) As such, Avraham would not want to be violate this holy day. Therefore, he had butter and milk prepared in anticipation that guest might arrive, but the rest of the meal was prepared on the spot.

The Uncountable Stars

In this week's parsha (15:5) HaShem brings Avraham Avinu outside and tells him to observe the uncountable stars and tells him that his progeny will be likewise uncountable. Rashi there quotes a Midrash that states that HaShem removed Avraham from the atmosphere and placed him above the stars to observe them. R' Chaim Kanievsky questions, why was this necessary? Why was it not sufficient to simply look at the stars from where he was?

He answers that we are taught in the adjacent commentary to Rambam's Hilchos Yesodei HaTorah (3:8) that there are a finite number of stars visible from Earth, 1022 to be exact. Beyond the scope of our vision there exists an abundance of stars which are too many to be counted. Being shown the stars from Earth was simply not impressive enough. Avraham had to be removed from Earth in order to appreciate the true extent of the berachah.

Ari S.said...

The number 1,022 is also seen in Ibn Ezra's Reishis Chachma (on astrology). He cites Ptolemy just like the Rambam mentions in a few places (i.e. hilchos kiddush hachodesh) that his knowledge of astronomy comes from the Greek sources. Ptolemy (in the Almagest) does have this number. It is pretty clear that he (and the rishonim) were aware that there were many more. In fact, the way Ptolemy and Ibn Ezra cite it is to show how the constellations are formed. It seems that this number refers to the bigger and brighter stars.

The average person can see approximately 3 - 4,000 stars (the faintest being about magnitude 6). Perhaps, another idea expressed in the pasuk could be that it is impossible to count them at once. Some are below the horizon at times and others seasonal. Some are only seen at northern latitudes and others at southern. Maybe Avraham had to go high above in order to get an angle above them to see them at one time.

Jewish people have been dispersed throughout many countries during our exile. This is often to our benefit because it provides a defense mechanism. It is much more difficult for an enemy to ever annihilate us because of this. Maybe we are being taught that you will never be able to see all the Jews in one spot to count because they will be dispersed. In the ensuing pesukim of the covenant, there are many references to the exile.

Quality not Quantity

Firstly, let me let everyone know that, b"H, the book is finally almost ready to go to print! The cover and typesetting have been completed and we are just going through it very quickly to make sure that everything is in order. Keep your eyes open for it, hopefully it should be in stores in about a month or so!!!

In the Parsha we find that Avraham Avinu is informed by Hashem that his children will be comparable to the stars. Many commentators explain this to be a description of the characteristics of the children and not that it represents the number of offspring. Based on Rav Yehonasan Eibshitz's explanation I would like to offer the following short explanation.

Unlike planets which reflect the light of the sun, stars produce their own light. Due to processes of nuclear fusion happening in the center of the star, the entire star is illuminated and radiates brilliantly. So too, every member of Klal Yisrael shines in his own right. He is not shining because of "reflected light" from others, rather, he has a brilliant core that can brighten even the darkest places.

Additionally, from our perspective many of the stars are not visible. Many of them are too far from us and we are unable to perceive their light. Others have interstellar dust and debris that block their light from reaching us. This, too, is expressive of the inner beauty of the nishamos of Klal Yisrael. Even if they have strayed very far away and their glory cannot be seen on the outside, or if they have external inhibitions which do not allow for their light to be seen on the outside; nevertheless, their inner beauty is present and shines!

Lastly, in this week's Parsha, Avraham Avinu is told by Hashem to walk in front of Him and be perfect. The Rambam, Ramban, and many others explain that this perfection is the same mentioned by Hashem in Sefer Devarim when He commands Klal Yisrael to be perfect with Him. Included in that mitzvah is the commandment to refrain from predicting via astrology. The Rosh's son Rebbi Yehuda felt that this mitzvah represents the essence of the entire Torah and that the reason for the elongation of the exile is due to our lack of observance of this mitzvah. To understand why please feel free to
download a free copy of it here.

Interesting Calendrical Facts About the Mabul

We are taught that the Mabul began at midday. (Bereishis 7:13) Rashi cites that the reason for this was to demonstrate that, with Hashem's protection, Noach was able to enter the Teivah in front of all the wicked people of his generation and none of them was able to harm him.

Rav Yehonasan Eibshitz zt"l offers an additional explanation that has to do with the way the calendar works. Rav Eibshitz mentions that the historic date which the dove found dry land in the year after the Mabul was the first of the first month and was a Shabbos. If so, then the year preceding this one, the year when the Mabul began, the first day of the first month was Tuesday. (Clearly Rav Eibshitz is using a regualry styled year in which half the months contain 30 days and the other half have 29. The months alternate with 30 then 29 and so forth throughout the year.) Since the first month was a Tuesday then the subsequent month, the month in which the Mabul started, started on a Thursday. Thus, the 17th of that month, the day which the Mabul started, was Shabbos. Since the Gemara teaches that rain on Friday night is a blessing, the rain, instead, began during the daytime as not to give the wicked people even one iota of blessing. (Taanis 23a) Rav Eibshitz continues that, additionally, the mazal of Shabbos daytime is Saturn which symbolizes mass destruction and that was befitting for the beginning of the Mabul. (See Rashi Berachos 59b and the Ibn Ezra's Reishis Chachma) (Tiferes Yehonasan Bereishis 7:13)

The World's First Boat?

For 100 years Noach toiled and endured much ridicule from his neighbours as he built the ark. Sure enough, Noach had the last laugh when the flood finally came and wiped out everyone else on the planet. Having completely denigrated Noach and ignored his warnings, the people were completely unprepared. However, the ark was nothing more than a large boat. Didn’t anyone have a boat of their own to escape the destruction of the flood?

This fascinating question was asked of me by R’ Sander Goldberg of Baltimore and he followed it up with a fascinating answer from his sefer נחל חיים (Page 30.) There is some discussion regarding the general climate and environmental conditions before the flood and how they were changed forever by the flood. One of the principal catalysts for these theories is the first reference to seasons after the flood (8:22) which seems to imply that there were no seasons beforehand.

מלבי"ם writes that before the flood planet Earth was not on the 23.5 degree tilt on which it finds itself currently. The tilt was as direct consequence of the environmental havoc wreaked by the flood. When the earth is not tilted the climate conditions throughtout the world are at complete equilibrium. That is to say that weather conditions are completely uniform throughout the world and throughout the year. There is simply no reason for conditions to be any different in one place from another. Cloud cover as we know it did not exist either. After all, a partially cloudy sky means that there are clouds over one part of the land and not over the other. Rather, the skies slowly became saturated with moisture uniformly and once every forty years, writes מלבי"ם, the entire earth would be drenched with rain and the process would begin anew. (This explains why the people were not overly taken aback by the flood when it began.) מלבי"ם also attributes the longer lives lived before the flood to the consistency of the climate.

(Now THAT's climate change!)

Another condition that would result from a world climate in equilibrium is uniform atmospheric pressure. Without varying pressure, there can be no wind. Wind is a result of air moving from a high pressure area to a lower pressure area like the air flowing out of a balloon. Before the age of the motor, all large boats relied on wind to move. If there were no wind, there would have been no boats. This explains why Noach’s project appeared so strange and also explains why no one else had any means to survive the flood.

(He goes on to explain that due to this extreme difference in global climate fermentation was something that did not happen before the flood and that explains how Noach could go so terribly wrong afterwards getting drunk - alcohol hadn't existed either.)

Sailing the Friendly Skies

Perhaps it was the fact that this week’s Parsha discusses a boat, but there was some interesting astronomical news this week that got me thinking about a certain passage from the Gemara in Horiyos (10a). There, the Gemara relays a story in which Rabban Gamliel and Rebbi Yehoshua were traveling on a ship. Rebbi Yehoshua had packed extremely durable food, whereas Rabban Gamliel packed meals befitting a standard seafarer. The ship was delayed and Rabban Gamliel’s supply was exhausted. Rabban Gamliel was only able to be sustained due to Rebbi Yehoshua’s careful planning. Rabban Gamliel inquired of Rebbi Yehoshua how he knew the journey would take so long. Rebbi Yehoshua responded:

".[כוכב אחד לשבעים שנה עולה ומתעה את (הספינות) [הספנים] ואמרתי שמא יעלה ויתעה [אותנו"

“There is a star that appears in seventy years and tricks the sailors. I said to myself that perhaps it will rise and trick us.”

It is common knowledge that ancient sailors were extremely dependent on astronomical knowledge in order to navigate. Without modern equipment such as GPS devices, the most accurate method of determining one’s position is based on the stellar positions. The stars move through the sky in very specific patterns. Some are always in the north and others in the south. With this knowledge, sailors can navigate the seas. Additionally, apparent celestial position changes based on latitude, so one can determine his latitude with extreme precision based on how high specific stars are from the horizon. Thus, if a “tricky” star were to “appear” it could be disastrous to the sailors because it could send them way off course.

Rashi explains that the celestial object mentioned refers to a star that rises once every seventy years. This star sometimes appears in the north and sometimes in the south. If the sailor, unaware of this star’s nature, were to see it in the north at the beginning of the journey and later, unbeknownst to him, it would change position then he would think he was traveling in one direction but would actually be going in the opposite direction. Rebbi Yehoshua was nervous that this would occur to them while they were on their journey so he packed extra durable food.

While much has been written throughout the ages expressing the symbolic meaning behind this passage, it is very unclear as to the identity of this “star” in the plain meaning of the text. “Regular” stars have set positions in the sky and cannot change from north to south, so it seems unlikely that it could be a regular star. The planets’ orbits do not have them rising once every seventy years and switching from north to south during that time so they are also not viable options.

At first glance one may think that this star is a comet. Comets move across the sky and could theoretically be good candidates for what is being discussed. There is only one comet that has a short orbital period that is easily seen by the naked eye and interestingly it happens to appear once every 75-76 years, Comet Halley (Halley’s Comet). This comet has been recorded by ancient astronomers at least as far back as 240 BCE, so it had been sighted prior to the time of Rebbi Yehoshua. If Rebbi Yehoshua was rounding the 75-76 years and referencing it as 70, then perhaps he was discussing this comet. This would be exceptionally fantastic because history gives credit to Edmund Halley as figuring out that the various comets recorded throughout history at 75-76 year intervals were all the same object and that this is that comet’s periodicity was 75-76 years. This “discovery” would not occur until over 1,500 years after Rebbi Yehoshua in the year 1705 CE!!!

There is one major problem with this assertion, though. The only arrival of Comet Halley during Rebbi Yehoshua’s lifetime would have been in 66 CE. Rabban Gamliel would have been an extremely young child at this time and in the ensuing parts of the story he is displayed as being older. (See Rashash, Pesachim 74a) Additionally, it would seem that he already achieved the title Rabban meaning that he was the Nasi and that did not happen until after the destruction of the second Beis Hamikdash which occurred in 70 CE. (See Gittin 56b; also see Seder Hadoros’ biographical synopsis of Rebbi Zeira for a discussion of the usage of titles in the Gemara indicating that the individual had already achieved that status at the time being referenced by the Gemara.) Thus, this story had to have happened well after Comet Halley’s appearance in 66 CE. To assert that Rebbi Yehoshua did not remember that the last appearance was in 66 CE and, therefore, was nervous that it would appear during the journey; or that he thought it would come sooner than 75 years this particular instance is unlikely. Rebbi Yehoshua mentions the 70 year interval in his statement; thereby displaying that he was aware of the orbital period. If he was aware of this fact, then it is unreasonable that he would not have remembered the last magnificent appearance of this comet which would have happened in his own lifetime and that he felt its periodicity was not subject to change.

I concede that I do not know what the identity of the object that Rashi is describing, however, I would like to suggest another approach to this passage. As I will explain, it would appear that Rashi had a variant text of this passage and I would like to offer a suggestion based on the text present in the standard editions of Gemara that we currently have. Perhaps, Rebbi Yehoshua was not stating that there is a star that appears every seventy years, rather, he was stating that there will be a star to appear in seventy years. He was not discussing a recurring event; he was mentioning that there was going to be a one time event that would happen in seventy years from the time being discussed in the Gemara. If this is, in fact, the case then one may ask why was Rebbi Yehoshua concerned that this star would appear prior to its seventy year date of arrival? The answer is that although based on Rebbi Yehoshua’s calculations the star would be coming in seventy years, nevertheless he may have realized that there was a margin of error in his calculations that would allow for this star to appear prior to that time. Therefore, he stated that there is a star destined to appear in seventy years, but because it was possible that it would appear sooner, he brought along extra provisions. The reason why this suggestion seems more likely based on the text in our Gemara is because the language used is:

"כוכב אחד לשבעים שנה."

and not:

"כוכב אחת לשבעים שנה."

The difference is that the text we have has the word “אחד” “one” in the masculine form and not “אחת” in the feminine. While this may seem like a minor variance, in truth it makes a world of a difference. If in the feminine it would indicate that the “one” is referring to the implicit, “פעם” “occurrence” and it is as if it says, “פעם אחת” “one occurrence.” Note that Rashi has this word in the feminine in his commentary to this passage. This reading of the text would be stating that the star appears once every seventy years and is a recurring event. Since in our text “one” is in the masculine form, it is clearly referring to the star and not referring to the periodicity of the star being seventy years. Thus, the translation of the entire sentence becomes, “One star will appear in seventy years, etc.” and is no longer, “A star appears once every seventy, etc.”

If this is the case, what then could this “star” be? We have ruled out regular stars, planets, and comets already, so what is left to be considered? Perhaps, Rebbi Yehoshua was referring to a new star appearing out of nowhere. Although uncommon, this has happened in extremely rare instances. When this has occurred it has not been that a brand new star was formed, rather, there was a star that was too faint to be seen by the naked eye which then brightened and became visible. At the end of large stars’ lives they experience an event called a supernova. Supernovae are essentially massive explosions during which time tremendous energy and radiance is emitted from dying stars. Supernovae that have become visible to the naked eye have occurred only a handful of times through recorded history.Over several months, these new stars then faded away and disappeared, only to be seen via telescope. Interestingly, the very first known one recorded in history happened in 185 CE. This is now referred to as SN 185 and made the news this week as observations by NASA’s Spitzer and WISE telescopes uncovered many more of the dynamics of how this supernova unfolded. Although Rebbi Yehoshua did not live until 185 CE, he would certainly have been alive and well 70 years prior to this and could easily have been aboard a ship with Rabban Gamliel in 115 CE. Keep in mind that the Gemara does not state that the actual reason for the delay of journey was because the star actually appeared, just that that was the reason Rebbi Yehoshua was prepared for such a delay. Supernovae are very unpredictable, perhaps leaving Rebbi Yehoshua doubting his accuracy and leaving a margin of error. In fact, if Rebbi Yehoshua was able to predict this one, his seventy year margin of error is far more accurate than even today’s predictions for supernovae!!! If this is the case, it is also astounding because even the ability to predict or understand supernovae is not considered to be known by man until the twentieth century and as previously mentioned, the accuracy with which Rebbi Yehoshua predicted this one is still not attainable by contemporary scientists!!!

The question then arises, why could such a star cause such confusion as to mislead a sailor. The rest of the sky would still have the same appearance and the sailor would just see an extra star, but would not head in the wrong direction. Upon further review, however, one can see that SN 185 may have actually been a little more confusing than just appearing as an additional star. The North Star and nearby Big Dipper are integral to celestial navigation as they are always positioned in the north. SN 185 occurred in the ancient constellation of Centaurus. In ancient times most people were not as familiar with those southern constellations since they can only be seen from more southerly parts of Earth. The area of Centaurus where SN 185 appeared would normally not be able to be confused with the Big Dipper and North Star, however, because they appear to have different configurations. The difference in configuration seems so apparent, but in fact is only so striking because this region of Centaurus is missing one bright star that appears in the Big Dipper. SN 185 flared up and appeared in that region so it is possible that a sailor would have glanced to the south quickly and mistaken this constellation for the Big Dipper!


The Big Dipper and North Star in the north:



Centaurus (prior to SN 185's appearance and post its disappearance) in the south:




Centaurus as it would appear with SN 185 in the year 185CE: