Laws of Kiddush HaChodesh - Rabbi Meir Menachem Mendel Glitzenshtein shlita

00:02 Speaker 1 You’re listening to “Lemaan Yishme’u,” a podcast from the Chabad Halacha Institute.

00:09 Speaker 2 The mitzvah of sanctifying the new month is a very interesting mitzvah. The Rambam’s laws on the subject are fascinating too—this whole section on sanctifying the new month. Not everyone knows that there is a mitzvah for beis din to calculate the astronomical movements of the sun and moon in the sky, so they can know when they will be able to sanctify the month. That’s one thing. There is another mitzvah: beis din must actually sanctify the month. In other words, it isn’t enough for us to know when Rosh Chodesh falls; it has to be sanctified. The Rebbe explains that there is something special here: the Jewish people, through beis din, have the power to sanctify time, to bring holiness into time. When beis din declares a particular day to be Rosh Chodesh, that determines when we celebrate Pesach and when we celebrate Sukkos. So beis din sanctifies the month; it sanctifies time. That is what we mean when we say, “Who sanctifies Israel and the festivals”: the Jewish people sanctify the festivals. That is the power given to a Jew to sanctify time. Here, we’ll try to give an introduction to the laws of sanctifying the new month. Of course, you can’t learn the entire Torah while standing on one foot, but we’ll try to provide an introduction so that anyone who wants to go on to study these laws in depth will find it much, much easier. I’ll say at the outset that what I explain here won’t always be one hundred percent precise—not the numbers, nor the diagrams and other things I’ll show later. I’m doing that deliberately to make it easier for the learner to understand. If we get into the finer details, it will become harder. So if you later

02:10 Speaker 2 study the subject and see that I wasn’t entirely precise, I’m telling you now that it was deliberate. I want to give you the basic framework so you can then continue studying the laws of sanctifying the new month. The first thing we’re looking for in the Rambam’s calculations is when the molad of the new month will be. On Shabbos Mevarchim, we all hear the announcement in shul: “The molad will be on this day, at this hour.” We’ll try to explain what the molad is, what it means, and exactly what happens astronomically at the molad, as we’ll see later. Why is it important for us to know the molad? Because the molad is the key to sanctifying the new month. Once I know when the molad occurs, I can begin to determine the Jewish calendar. In their time, beis din would receive witnesses. The witnesses would come to testify that they had seen the new moon; beis din would question them and then sanctify the month. Of course, as we said earlier, there is a mitzvah to calculate. Beis din would make the calculation beforehand, before the witnesses arrived, to know whether sighting the moon was possible or not. But of course, Hakadosh Boruch Hu wanted this to happen even though beis din knew how to calculate and, in effect, didn’t need the witnesses—they could determine it themselves. As we said earlier, “Who sanctifies Israel and the festivals”: there is a significance to the sanctification of time coming through us down here, through our coming forward ourselves, testifying, and sanctifying the month. So the key to this whole subject, to all the laws of sanctifying the new month, is the molad: knowing when the new moon is born. Each of us knows that when he goes outside and looks at the heavenly bodies, with the sun

04:16 Speaker 2 most people don’t notice changes. They see the sun rise in the east and set in the west. There are changes in where the sun rises—significant changes—but the average person doesn’t notice them. He always sees the sun rise in the east and set in the west. He knows that sometimes it rises earlier and sometimes later, but he doesn’t really see any change in the sun itself. With the moon, everyone sees changes; even a small child sees them. Sometimes the moon is just a small sliver, a little banana shape. It grows, and everyone knows that at the beginning of the month it’s small and then starts to grow. On the fifteenth of the month it reaches its fullest point, when it is a complete circle. After that it starts getting smaller and smaller, until at a certain point—and I’m telling you this now—you can’t see it. For almost forty-eight hours, the moon can’t be seen; it disappears. Later we’ll also explain why the moon disappears from our sight. Then it renews itself again: we begin to see the new moon. Seeing the new moon is what the molad is about. The moon is born anew; we begin to see it again. Before we talk about the molad, I want to explain the sun first. Then I’ll explain the moon, and after that I’ll explain what the molad is. The sun goes around the earth. That’s what the Rambam writes, and that was the old view—that the sun goes around the earth. There are several letters from the Rebbe on this subject, but this isn’t the place to discuss it. For now, we’ll speak according to the Rambam’s approach, in which the sun goes around the earth. How long does it take the sun to make one complete circuit around the earth? It takes three—

06:15 Speaker 2 three hundred and sixty-five days and six hours. That’s how long it takes the sun to go all the way around the earth, one complete circuit. You’ll immediately ask me: if the sun takes a year to go around the earth, why do we have day and night every twenty-four hours? Shouldn’t it be daytime for half a year and nighttime for half a year, since it takes the sun a year to go around? We’ll get to that in a moment. But let’s see what happens with the sun. Here, for example, we have a sphere, and if you look at the center, you’ll see the earth. This outer sphere represents the heavens. In other words, we’re looking as though someone outside were viewing the sphere of the heavens with the earth at its center. That’s simply to make it easier to picture. Let’s say the sun is here. It makes a complete circuit around the earth over three hundred and sixty-five days. As it goes around, the earth is divided into two halves, and the sphere of the heavens is divided into two halves as well. We have the Northern Hemisphere and the Southern Hemisphere, separated by the equator. We also divide the sphere of the heavens into two parts. There’s the northern part. What you see here isn’t the equator, because the equator is on the earth. It’s a kind of conceptual line dividing the sphere of the heavens in two: the northern part and the southern part. In the sky there is a band called the zodiac. That is, there are certain stars arranged in twelve groups, each group being a particular sign of the zodiac. During the Six Days of Creation, that group was located

08:19 Speaker 2 As we’ll see right here in a moment. The constellations encircle the Earth, the universe, but they are not on the equator. In other words, the zodiac is tilted twenty-three and a half degrees from the equator. Here we can see the constellations beginning to rise: Aries, then Taurus, Gemini, reaching the top, and then beginning to descend: Cancer, Leo, Virgo. Then the constellations descend into the southern hemisphere: Libra, Scorpio, Sagittarius, Capricorn—Capricorn is at the bottom—and then they begin to rise again: Aquarius, Pisces. In other words, it’s the same circle. When we draw a circle around a sphere, it’s still the same sphere and the same circle; the circle is just tilted rather than level. Now, we said that the sun moves forward each day, and that it takes 365 days—a year—to circle the Earth. So that’s a little less than one degree a day, because every circle is divided into 360 degrees. That’s a convention: every circle is divided into 360 degrees. It isn’t a question of size; it’s a convention. So this circle is divided into 360 degrees, and that circle is divided into 360 degrees too. The sun moves forward about a degree each day. Twelve degrees, twelve months: in Nissan it’s in Aries, and it moves on. In Iyar, the sun moves through Taurus, then in Sivan through Gemini, and so it goes down. What we can already understand is that for six months the sun is among the northern constellations, in the northern part, and for six months it is among the southern constellations. We’ll try to understand how day and night come about. If the sun moves along here, and it takes half a year to travel through these constellations—

10:39 Speaker 2 the northern ones—and half a year through the southern constellations, then how do day and night come about? I’m explaining this according to the Rambam’s approach. He explains that above all the spheres—with the Earth at the center and the spheres of stars circling it—there is a sphere called the daily sphere. It isn’t something we can see. By the way, it’s very interesting that in chapter 3 of Hilchos Yesodei HaTorah, the Rambam explains that these spheres have more intelligence than human beings and less than angels. In other words, we’re talking about something more spiritual, more intelligent than a person. That’s what the Rambam writes. Less intelligent than the angels—something between a person and an angel, between a person and the angels. Perhaps something between the physical and the spiritual. We don’t see them. The Rambam writes that they are refined; we don’t see them, but they exist. They are spheres. This sphere is called the daily sphere, or, in the terminology of astronomers, the driving sphere. What does “driving sphere” mean? Let’s understand what happens here. For example, at the beginning of Nissan, the sun is at the beginning of Aries, and it starts moving upward by about one degree each day. Which way does the sun move? From west to east. After all, we see the sun rise in the east and set in the west. That’s true; we’ll soon understand why. The sun itself, as it moves along the zodiac at a rate of about one degree a day, moves from west to east. In other words, it rises here, from west to east. But each day the driving sphere, this great ninth sphere, turns the entire universe beneath it: the sun and the moon, Venus and Mars, the other planets, and the other stars and constellations we see in the sky. The driving sphere carries them back around in twenty-four hours. So the sun itself moves from the west—here is west—

12:57 Speaker 2 and here is east. It moves from west to east, while the daily sphere takes it through a complete rotation over the course of a day, so it circles the Earth at this position. For example, when the sun is at the end of Taurus, around the end of Iyar, the path on which it circles the Earth will be along this line, because this is where the sun will be at the end of Iyar. By then the sun will be here, higher up. Here is the sun at the end of Iyar, at the end of Taurus, and then it moves onward. But the daily sphere carries it from east to west, bringing it back from east to west, so its circuit around the Earth will be up here. That is in our summer, because Eretz Yisroel is, broadly speaking, in the northern part, at about thirty-two degrees. Eretz Yisroel is here—approximately, right? When the moon—when the sun is in the northern constellations, it is closer to the northern hemisphere. By contrast, when the sun is in the southern constellations—for example, right down at the bottom in Capricorn, at the end of Sagittarius and beginning of Capricorn, around Teves—it circles the Earth down below. Its circuit is down here. This also gives us an explanation, though it isn’t our subject right now, of why in the northern hemisphere the period from Tishrei to Nissan is more of a winter season, while in the southern hemisphere that very same period is summer. Then it reverses: from Nissan to Tishrei, it’s summer here in the northern hemisphere and winter in the southern hemisphere. Why? Because it depends on which side the sun is closer to: the north or the south. In our summer here in Eretz Yisroel, the sun is on the northern side, and Eretz Yisroel is on the northern side. So all the countries north of the equator—

15:18 Speaker 2 have summer then. By contrast, for example, now in Teves the sun is down here. It is in the southern hemisphere, and this is where it makes its circuit. As the daily sphere drives it around the Earth, its circuit is down here. It is close to the southern side and far from the northern side, so in this case it is winter for us and summer in the rest of the world. So far we’ve explained the sun’s motion. It’s very important to understand both its daily motion and its yearly motion. The sun’s daily motion—let’s sum it up briefly—is that the sun moves slowly, about a degree a day, from west to east. It moves along its own sphere. That’s its daily motion. The daily motion that turns it—the sun gives us day and night—is the daily sphere turning it from east to west, and that produces day and night for us. So, in summary, when I look up at the sky now and see the sun, and I ask any of you, “Is the sun moving west or east?” the answer is that both are correct. Through the sun’s own motion, it is slowly moving from west to east. I can’t see that; it isn’t noticeable. But through the daily sphere, it moves from east to west, rotating rapidly and making roughly one complete circuit in twenty-four hours. With the moon there are many, many details. As it says, “The sun knows its setting; the moon does not know its setting.” The moon’s motion involves a number of different movements, but I won’t go into the details. I’m speaking in very general terms. The moon also circles the Earth, and generally its course corresponds to that of the sun. In other words, the sun circles the Earth along the zodiac, and broadly speaking, the moon also circles the Earth along

17:21 Speaker 2 The zodiac. Basically, they both travel along the same path—not exactly the same path. The moon sometimes veers a little to one side and sometimes a little to the other, but broadly speaking, the moon too travels along the zodiac together with the sun. There is, however, a big difference between the moon’s movement along the zodiac and the sun’s. The sun makes a full circuit of the zodiac in about a year—365 days, as we said. For the moon to make a full circuit and return to the same point takes about 27 and a third days. After 27 and a third days, the moon reaches the same point. With the moon, just as with the sun, as we said earlier, the moon itself moves from west to east, while the daily rotation carries both the sun and the moon all the way around the earth from east to west. But as we said, the moon moves about thirteen degrees a day, which is a lot—you can notice it. For example, you can check this yourselves: go outside and look. If the moon was at a certain point one evening, the next evening, at the same time, it will no longer be at that point. It will be about thirteen degrees farther west. Every day it moves about thirteen degrees forward. We’ve understood the movement of the sun and the movement of the moon. Let’s move to another point. Set that point aside; we’ll cover one more point and then put the puzzle together. The moon has no light of its own. The sun has light; it is a source of energy and shines in every direction. The moon has no light of its own, so it always receives light from the sun. The sun shines on the moon, and the moon is always, always half—

19:47 Speaker 2 Look at the diagram in front of you. You can see that the moon always receives light from the sun on one half. It is always half lit and half dark, because the moon receives its light from the sun. How do we see the moon? The moon reflects light. Down here on earth, we can see the light it receives from the sun. So, as the moon moves away from the sun—let’s start before it moves away, when it is at the same angle as the sun. The sun is here, the moon is here, and the earth is below. They are in a straight line. The sun shines on the moon, as you can see now in diagram number one. You can see the sun shining on the moon. The lit side faces the sun; the dark side faces the earth. In that situation, we cannot see the moon. There’s no way. Now about seven days pass. Look at diagram number two. After seven days, the moon has moved away from the sun. In those seven days, the sun has moved about seven degrees. The moon has moved seven times thirteen. That means it has moved almost ninety degrees, or something like that. It has moved a great deal. The moon has moved, so a fairly large gap has opened between them. The sun shines on it—you can see this in the diagram. The sun shines on the moon. The part of the moon facing the sun is lit, but when we look from down here, we see a quarter of the moon illuminated. On the fifteenth of the month, look at diagram number three. You can see the positions of the sun, the earth, and the moon. Here the earth is almost between the sun and the moon, and the sun fully illuminates the moon. Why isn’t there an eclipse—

22:08 Speaker 2 A solar eclipse? I mean, a lunar eclipse? Because, as we said, the moon is not exactly in a straight line. Sometimes it veers a little north, and sometimes a little south, so it is not precisely in line. That is why we don’t have an eclipse every month. If it is in the same line, that is exactly when an eclipse occurs. But it isn’t in the same line; sometimes it is to the south and sometimes to the north. In this situation, on the fifteenth of the month, the sun fully illuminates the moon, and we see a full moon. After that, the moon moves even farther away from the sun. Look at diagram number four. Here we see the situation around the twenty-third of the month. By the twenty-third, the sun has moved only twenty-three degrees, while the moon has already traveled three-quarters of a circle and is very far away. Here, too, the sun shines on the moon, but from the other side. Earlier it shone from this side; now it shines from the other side. And we on earth again see only a quarter of the moon. We don’t see more than that as we approach the end of the month. Then, after 27 and a third days, as we said, look at diagram number five. You’ll see that the moon has completed a full circuit. It has gone all the way around the earth, but the sun has moved ahead of it. During those 27 days, as you can see in the diagram, the sun moved twenty-seven degrees. The moon has completed a full circuit, but it hasn’t caught up with the sun. The sun still shines on it, and there is reflected light that we can see. So it takes another two—two and a half days or so. The calculations for the moon aren’t exact. Every month is different. Every month is different. The moon’s cycle may repeat only once in 360,000 years. Every month the moon has a new birth,

24:06 Speaker 2 A new time. And as you can see in diagram number six, this is the situation when the moon has come around again and is positioned beneath the sun. Here we are again: soon there will be a molad, a new moon. Right now, it’s like what we saw at the beginning in diagram number one. The sun, moon, and earth are in a straight line. The moon’s lit side faces only the sun. We, down here on earth, cannot see it, and now we wait for the moon to move a little farther forward. The moon will move forward, the sun will shine on it, and we’ll see the little sliver of reflected light—the small crescent of the moon. Now let’s put a few things together. We’ve understood the movement of the sun, discussed the movement of the moon, and discussed how far the moon moves away from the sun before there can be a molad. In other words, after the moon, earth, and sun line up, two things have to happen for us to see the new moon. First, the moon has to move away from the sun. It has to move a sufficient number of degrees away. I won’t say exactly how many degrees right now, but it has to move away from the sun. Then there’s a chance it will reflect enough light for us to see the new moon. If it hasn’t moved away and remains close to the sun, we won’t see any reflected light. That’s the first thing we’re waiting for from the moon: move far enough away. There’s one more thing we need. After all, the moon is there all the time; it doesn’t disappear. If you pay attention, toward the end of the month, you’ll often see the moon in the east as the sun rises—not in the west, in the east. We see the moon. It still has to get closer to the sun; it’s approaching. The sun is there, and the moon is here. We see it, we see it, and then suddenly, after

26:24 Speaker 2 For an hour, three-quarters of an hour, we stop seeing it. Why do we stop seeing it? Not because it isn’t there; it hasn’t gone anywhere. It’s because the sun is an immense source of light and power, and the moon is simply overwhelmed by it. The moon is completely overwhelmed by the sun, but it’s still there. The sun shines on it, but because of the intensity of the sunlight here on Earth, we can’t see the reflected light; it’s minuscule. In other words, for us to see the new moon, the sun’s light has to be dimmed in some way. If the sunlight isn’t dimmed, we won’t be able to see the new moon. Before I move on to the next stage, I want to add one more small introduction. Every person has a horizon. What does “horizon” mean? Of course, our eyes have limits to how far we can see. But if we stand somewhere with no mountains, hills, or buildings—if I stand on a plain and look at the dome of the sky—what can I see? I can always see ninety degrees in every direction. For example, if a person is here—let’s just say this is the Earth—standing here, he can see all the stars in the sky up to here and up to here: ninety degrees on every side. Anything below that is beneath his horizon. He can’t see those stars because they’re below the horizon. Every person, wherever he stands in the world, has his own horizon. This is very relevant—not to our subject here, but to sunrise and sunset, and calculating their times. Every person has his horizon,

28:24 Speaker 2 the ninety degrees in every direction that he can see. We need to see where the sun passes across that dome of sky, how long it takes, when it disappears below his horizon, and when it enters his horizon. When it enters his horizon, that’s sunrise; when it leaves his horizon, that’s sunset. That’s a different calculation and a different subject, but every person has a horizon. Now let’s look at an example of what happens with the sun and the moon. Here, the sun has already—the sun is, for example, here. We said that the moon completes a full orbit around the sun in twenty-seven days. After about twenty-seven and a third days, it has reached this point. It has come back here—a full orbit. Meanwhile, over those twenty-seven days, the sun has advanced another twenty-seven degrees or so. The moon is here in the meantime. The moon has to catch up with the sun, and then after about twenty-nine and a half days—well, let’s be precise—the sun and moon are on the same line. Now the moon starts moving and opens up a distance from the sun. Let’s say that a day later it’s here. The sun is here and the moon is here. Okay, they’re advancing in this direction, but the daily rotation carries them in this direction. Then we reach this position. Let’s say this is a person’s horizon. A person standing here can see the ninety degrees from where he is to this point. Anything that crosses this line will be below his horizon. Now, a person who is here—for example, the same person in Jerusalem—let’s put him in the second position. He’s no longer here; he’s here. Okay, so this person can see ninety degrees in this direction and ninety degrees in that direction.

30:28 Speaker 2 He can see this entire half, and a little more over here, because he’s higher up. Now the daily rotation turns and turns. What has happened at this point? The sun has set; it has gone below the horizon. The moon has not yet set. And because the moon has not yet set, this is exactly when we can see the new moon: it has opened up a distance from the sun. Of course, it has to be far enough from the sun. First, as we said, it must be reflecting light toward Earth. That’s the first thing. And in addition, the sun has to set. If the sun has set and the moon has not, then we can see the new moon. So, to sum up, we will always see the new moon in the west, not the east, at sunset—after the sun has set, while the moon has not yet set and has moved far enough from the sun to reflect light. The sun has already set, so it doesn’t interfere with our view of the moon. The sun’s powerful light no longer gets in the way. We see the new moon; that is what the new moon’s appearance is about. So if one of the witnesses comes to the beis din and says, “I saw the moon in the east,” I’ll tell him, “You don’t know what you’re talking about.” Even if he says it was in the west, of course—as I said at the beginning of the class, we’re not going into the details. There are many details concerning the moon. I can tell you that someone who isn’t an astronomer and doesn’t know exactly how he saw the new moon won’t be able to testify before the beis din, because he’ll get tangled up within two minutes. They’ll ask him how high it was, which way it was, where the horns pointed, and how it was tilted. Because the beis din

32:26 Speaker 2 calculates all of this. As I said, sometimes the moon is north of the sun and sometimes south of it. It has a latitude and a longitude, and various paths it follows, broadly speaking, around the zodiac. The sun always travels along the zodiac, but the moon doesn’t quite do that. Sometimes it moves north, sometimes south; sometimes it moves farther away, and the angles change. Every such angle matters a great deal. First, there’s the distance, which determines whether there’s reflected light or not. Second, we need to know whether enough time will pass between the sun setting and the moon setting for us to see it. For example, if the moon is here, as in our example, along the zodiac, and there’s enough distance—say, nine degrees, as the Rambam writes—then that’s fine. The distance is sufficient. The sun has set, and we’ll be able to see the moon. But if the moon is here, there may still be enough distance. That sometimes happens. As we said, if it’s to the north or south, the distance can be sufficient. In theory, that’s fine, but the sun sets and a minute later the moon sets too. The daily rotation carries both of them, so the sun sets and the moon sets three minutes after it. There’s no chance of seeing the moon that evening. The distance is there, but the moon sets too quickly, and we won’t manage to see it. The Rambam’s Hilchos Kiddush Hachodesh is divided into several parts. I’ll give a brief overview of how the Rambam divides these laws, to make them easier to study. From chapter one through chapter five, the Rambam discusses technical matters: how the witnesses are received, who the witnesses are, who sits on the court for intercalating the year and who doesn’t, how they send the

34:27 Speaker 2 The messengers would inform people outside Eretz Yisroel whether the month had been extended or not. All the technical matters are covered in chapters 1 through 5. Chapters 6, 7, and 8 are a subject of their own: the Hebrew calendar. There, the Rambam discusses how to construct a Hebrew calendar from A to Z. Someone who studies these three chapters will understand the Hebrew calendar, even if he doesn’t know exactly what a molad is or how the astronomical side of it works. He’ll learn the numbers and understand the calendar itself. Chapters 9 and 10 complete the discussion of the Hebrew calendar. There the Rambam discusses the tekufos—the seasons—and the two methods we have for calculating them. In chapter 11, the astronomical discussion begins, and the Rambam gives a general introduction to bring us into this subject. He doesn’t yet say much about the sun or the moon; he’s mainly introducing us to it. In chapters 12 and 13, the Rambam discusses the movement of the sun. There is its mean motion and its true motion—an average position and an actual position. Chapters 14 and 15 discuss the movements of the moon, which, as I said, are more complicated. If the sun has one sphere, or something like that, the moon has four spheres. Several movements have to be calculated together to determine the moon’s position. In chapter 16, the Rambam discusses the moon’s latitude. As we said, sometimes the moon is farther north and sometimes farther south; it moves back and forth in that respect. There the Rambam gives the calculation: how do I determine

36:20 Speaker 2 whether the moon is currently to the north or to the south? And in chapter 17, we get to the icing on the cake: we put together everything we learned earlier. After all, what are we trying to determine throughout the Rambam’s Hilchos Kiddush Hachodesh? We aren’t interested in where the sun or the moon is for its own sake. What matters is whether it will be possible to see the new moon on a particular evening, when it is due to be seen. That is what the beis din calculates. In chapter 17, the Rambam combines the movements of the sun and the moon with what we call the first longitude, second longitude, first latitude, and second latitude. We calculate all these movements together. The Rambam then gives rules: if the distance is such and such, there’s no chance it will be seen; if it is such and such, it will certainly be seen. If the distance falls between those values, then you start calculating—checking the latitude in one direction or the other and, as we said, combining those two factors: whether the moon has moved far enough away, and whether enough time will pass between sunset and moonset for it to be seen. In chapters 19—17—uh, 18 and 19, the Rambam adds further details about the zodiac belt and explains a few other astronomical matters. That’s it for today. Of course, we could go on at length, but anyone who studies what we’ve learned now, delves into it, and understands it well will find it easier to begin understanding what the Rambam explains in Hilchos Kiddush Hachodesh.