Science in the Torah

Torah and science – Astronomy: the moon’s renewal

How Long Have We Known About the Time It Takes for the Moon’s Renewal?

Is it possible that the Torah which was written thousands of years ago would possess precise astronomical information which NASA in America and German astronomers only recently attained through advanced electronic instruments?

Amazingly, the answer is yes!

When the new month is beginning, it takes on the shape of a thin crescent and then waxes until the entire round moon can be seen in the middle of the month. Then the moon starts to wane until it disappears and a new moon starts again. The day when it begins its renewal is the beginning of the Hebrew calendar month. The amount of time that passes from when one moon begins until the next is called a synodic month.

Jewish holidays are determined according to the day of the lunar month, as designated in the Torah. (For instance, the holiday of Passover is on the 15th day of the month of Nissan and the month of Sukkos is on the 15th day of the month of Tishrei, etc.)[1] There is therefore great legal importance ascribed to determining the first day of the lunar month when the new moon begins.         

The Talmud (Rosh Hashana 25:1) relates:

“Once the heavens were covered with clouds and the shape of the moon was seen on the 29th of the month. The people thought it was the beginning of the new moon, but Rabban Gamliel told them: I have a tradition from my father’s house that the new moon cannot begin in less than 29 and a half (12 hours) days, 2/3rd of an hour and 73 parts.”[2]

Rabban Gamliel testifies that he received an oral law from earlier generations of the Jewish royal dynasty (which received it from their ancestors going back to the Giving of the Torah) that the moon’s renewal cycle is exactly 29 and a half days, two thirds of an hour, and 73 parts.

Let us sum this up in contemporary time units:

A summary of the calculation according to the Torah:

29.5 days + 2/3 of an hour + 73 parts of an hour.

1. 2/3 hour = 720 parts (since an hour is divided into 1080 parts. See note ?)

2. 73 parts + 720 parts = 793 parts

3. 793/1080 parts of an hour = 0.734259 hour.

4. 0.734259 hour = 0.03059 of a day.

5. 0.03059 + 29.5 days = 29.53059 days

  Conclusion: The New Moon renews itself every 29.53059 days.

Carl Sagan, the chief scientist of NASA, the American Space program wrote a book in which he calculated the length of the lunar month. To our amazement, he concludes that the amount of time for the moon to renew itself is: 29.530588, which is for all purposes 29.53059 days (the difference is one particle of a second)!!! [The measurement was carried out with the assistance of a glass prisma which American astronauts left on the moon, laser rays sent from Earth to the prisma, powerful telescopes, and an atomic watch. It should be emphasized that without these devices which are only relatively recent, modern science would be unable to achieve such an exact result.]

A more advanced study was carried out in Berlin, Germany. This study further narrows the gap in the parts of second between the Torah and modern science. It concludes that the length of the moon’s cycle is 29.530589 days!!!

We, who know with absolute certainty  that the Torah was given to our people from the Creator of the universe, know that the details of a number of the commandments revealed many mysteries of nature which the Torah saw fit to teach so we can fulfill the command-ments according to law.[3]  The above-mentioned example (which is necessary for determining the dates of the Torah’s holidays) is one among many, but it is sufficient for an unbiased intelligent person to reach the ineluctable conclusion that human intelligence could not have written the Torah. [We also understand why Rabban Gamliel did not hesitate to rule against the people who claimed to see the shape of a moon, based on the fact that the tradition he received from his ancestors did not permit seeing a new moon at that time. Today, in light of scientific findings, it is clear to all that the moon’s phase could not be seen during the 29th day and what appeared to be the moon had to be a reflection from the clouds. Yet, it was clear to Rabban Gamliel even then! He knew that the source of his information was the Creator’s Torah, and the Creator of the universe doesn’t make mistakes!! ][4]

In the meantime, we are patiently waiting for science to advance and take another step towards the Torah, and figure out another part of an hour until it reaches the absolute correct length of the synodic moon.

For that is your wisdom and your understanding in the eyes of the peoples, who will hear all these statutes and say, ‘Only this great nation is a wise and understanding people!’ (Deut. 4:6(

What wisdom and understanding in the eyes of the people is it referring to? The calculations of the calendar and the zodiac movements. Whoever knows how to calculate the calendar and the zodiac movements and doesn’t do it, the verse says about him, ‘and the work of the Lord they do not regard, and the deed of His hands they have not seen.’ (Isa. 5:12)” (Yalkut Shimoni, V’eschanan 4(.


How Many Stars are in the Pleiades Star Cluster?

In the cluster of stars called “Pleiades”, which is 300 light years distant from us, the eye can only discern 6 stars. An especially sharp eye in maximal visual conditions can see a seventh and eighth star. For many generations, astronauts thought that Pleiades contained 8 stars. (By the way, the name Pleiades translates to “Subaru” in Japanese. The stars in the well known auto manufacturer’s logo represent the Pleiades according to the number that a normal eye can see.)

Then the telescope was invented in 1609 by Galileo Galilei, and it was improved until light refraction telescopes were invented and more recently, radio telescopes. It turns out that besides these 8 stars, the Pleiades contains more than 100 stars that a normal eye cannot detect. (See more details in the Hebrew-language book “The Hosts of Heaven”,Vol. 2, page 134 and continuation by the highly regarded astronomer Dr. N. Vidal. See also the Hebrew Encyclopedia Vol. 20 page 674.)

The Talmud (Brachot 58b) says about it:

What is Pleiades? Samuel said it has about 100 stars. Some say that they are gathered and near each other, and some say that they are scattered.” See Rashi’s commentary that the question “What is Pleiades?” means what are its main stars, even though there are more than 100 of them.

The Talmud was written about 1,500 years ago. At that time, the telescope had not been invented and how the human eye saw the Pleiades completely contradicted the Talmud’s words which appeared to be a wild exaggeration. This is why the non-Jewish astronomers did not accept the Talmud’s statement despite the general admiration which they had for the opinions of the Jewish sages, particularly where it concerned astronomy.

Nevertheless, the Talmudic sages didn’t budge from their beliefs and proudly and boldly upheld them because they knew that the source of their information was the Torah of the One Who created the entire universe including the Pleiades star cluster. He knew what He had created, whether it could be seen by human eye or not. This information was passed down from the sages to the generations after them, so that this tradition was ancient until it — like the rest of the Oral Tradition — was finally written down. Over the generations, the only dispute that arose over this tradition was the minor detail of whether the many invisible stars in Pleiades were close together or scattered apart. This is truly amazing.

* * *

Who Was the First to Know That the Earth Was Round?

Ancient peoples believed that the world was a flat surface standing on the tails of three giant whales. Some believed that the world was supported by four immense elephants standing on the back of a huge turtle that was swimming in an infinite ocean. Either way, everyone was sure that earthquakes were caused by the movements of those holding up the world… The theory that the world was round was considered unlikely and even highly irrational.

The Greek wise men claimed that the world was round. But the popular belief for many hundreds of years to come among nearly all of mankind was that the world was flat, or at most — in the shape of a dome.

However, after Columbus discovered the American continent five hundred years ago (in 1492) while attempting to find a way to India by traveling west, this encouraged many others to set out on similar sea journeys. People began to realize that the world was round, despite the idea of a flat world still being popular among the masses at that time.

This understanding of a round world became more accepted, and in recent years it received a final and indisputable scientific stamp after seeing pictures of the Earth from space. Today, the theory of a flat world standing on the backs of whales and elephants brings a smile to our faces. Nevertheless, if we remember that the only evidence which people of those times had was the horizontal surface of their fields and the mountains, they had no reason to assume that the world was round. Before Newton discovered the power of gravity, it didn’t make sense to say that a world populated by people and animals (and various objects) is round. After all, were the people living on the other side of the world standing on their heads with their feet up? How come they don’t fall off the earth?

However, the holy Zohar (Lev. 10a), which was written 2,000 years ago, has the following information, and even says that it was cited from an even older book which was written by Rabbi Hamnuna Saba:

The inhabited earth is round like a ball[5] , and some live below, at the bottom of the ball, and some above. All the people that live in various parts of the globe look different in their coloring, face features, etc. because of the difference in each place’s atmosphere. But they stand upright like all other men. There is a place in the world where when these have light, those have dark, and when these have day, those have night. There is a place in the world where the daytime is long and you will only have nighttime for a short time… For the verse says, ‘I shall thank You for I was fashioned in an awesome, wondrous way; Your works are wondrous.’ (Psalms 139:14). This secret was given to the sages of the Torah.”

Several impressive facts are mentioned in the Zohar’s short, powerful passage:

1. The world is shaped like a ball, and is not flat as most of the people believed then.

2. The earth does not stay in its place permanently but it revolves on an axis.

3. People live not only on the top half of the earth but also on its bottom half.

4. People living on the bottom half of the earth stand on their feet like people on the top half. This is the concept of gravity. (Newton only discovered gravity 300 years ago!)

5. When some parts of the world have day, others have night, and when some have night, others have day.

6 . There is a place that is sunlit most of the day and the night is very short.[6]

The Jewish sages were aware of the fact that the information they possessed was unknown to the men of science in their times, and it may have even sounded incredible and strange to them. At the end of the Zohar passage mentioned above, the sages define this information as mystical knowledge (sod). The sages also state that the source of their information was not any exploration they carried out, but a tradition which those who knew the Torah’s secrets received. The source was not nature but Torah.

Isn’t this sufficient to prove that the Torah was given from heaven?



[1]. The Torah relates that this is one of the purposes why the heavenly lights were created: “And God said, “Let there be luminaries in the expanse of the heavens, to separate between the day and between the night, and they shall be for signs and for appointed seasons and for days and years.” (Gen. 1:14).

[2]. Parts are not referring to “minutes” of which there are 60 in an hour, but to smaller segments of an hour which are divided into 1080 parts (equal to slightly more than 3 seconds). Maimonides states (Laws of Sanctifying the Moon 6:2): “Day and night are always considered to be twenty-four hours, twelve [hours] of daylight and twelve [hours] of night. An hour is divided into 1080 units. This number was chosen because it can be divided in halves, fourths, eighths, thirds, sixths, ninths, and tenths.” A large number of hour parts was chosen to help achieve maximum precision.

[3] “The Lord spoke to Moses and to Aaron in the land of Egypt, saying, This month shall be to you the head of the months; to you it shall be the first of the months of the year.” (Ex. 12:1-2). At that time, G-d gave over to Moses our Teacher the rules of the moon’s calculations and the traditions of its exact laws. He informed him how to institute leap years and determine months.” (Midrash).

                [We possess various testimonies demonstrating that this important information with other various scientific information trickled down from the Jewish people to the non-Jewish nations such as the Babylonians and the Greeks, who made use of them. (Rabban Gamliel’s words show that this precise information was already in the hands of Jewish sages hundreds of years before.)

                What is interesting is that not only Jewish sources [such as Maimonides (Sanctifying the Moon 17:24), Rabbi Judah Ha-Levi (Kuzari Section Two:66) Shvilei Emuna (8, beginning from dah) and others] speak about Jewish scientific information which reached the non-Jewish world, but even ancient non-Jewish men of science mention this, such as Origen Against Celsus (Book 1 Chapter 15): “It is said, moreover, that Hermippus has recorded in his first book, On Lawgivers, that it was from the Jewish people that Pythagoras derived the philosophy which he introduced among the Greeks. And there is extant a work by the historian Hecataeus, dealing with the Jews, in which so high a character is bestowed upon that nation for its learning.”]

[4] In contrast, the civil (Christian) calendar which, for some reason, is also widespread among the Jewish people, is based on the solar year. The human inventors of this calendar of course did not know the exact length of the year, and their calendar developed an increasing gap until finally in 1582, the Vatican church decided to eliminate 10 days to fix the calendar from falling behind. October 4 was followed by October 15. And since this correction was the result of human logic, this improved calendar is still deficient. Dozens of years ago the UN was submitted an offer for a new calendar which would fix all the problems of this calendar.

[5] For more about the world’s roundness, see Zohar (Breishit 15) “Rabbi Yossi says: We already learned from the heads of the yeshiva that the world is round like a ball.” These indisputable words about the world’s round shape also appear in the Midrash Rabba (Bamidbar, Nasa 13) and the Talmud Yerushalmi (Avoda Zara 13). See also the Tosfos Avoda Zara 41.

[6]Today we know that this is the situation for half of the year in the North Pole and half of the year in the South Pole.



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