Lunar Observations in Rosh Hashanah

The Daf Yomi cycle just finished studying Masechet Rosh Hashanah. Mazal tov to all those who have completed this study! In Masechet Rosh Hashanah observations of the Moon play a very significant role. A major topic of study in this tractate is how the ancient Jewish “calendar” worked. In fact, it was not really a…

Black Holes in Pesachim

The very first line of Pesachim focuses attention on one of astronomers’ favorite topics: light! Or does it?

Shavuot, Philo, Astronomy and Pythagoreans

The first century CE Jewish philosopher Philo of Alexandria, in glowing terms, describes the holiday of Shavuot and its underlying reasons based on mathematics – and astronomy!

The Menorah and Planets

Chanukah is an opportune time to share this interesting midrash about the Menorah and planets…


In the less well known Pirkei DeRabbi Eliezer we find a less ominous, more astronomy focused talmudic take on eclipses…

Abraham and the First Planetarium

In Parshat Lech Lecha, we find Genesis 15:5, a great verse for astronomical commentaries and homiletics, for fairly obvious reasons: וַיּוֹצֵ֨א אֹת֜וֹ הַח֗וּצָה וַיֹּ֙אמֶר֙ הַבֶּט־נָ֣א הַשָּׁמַ֗יְמָה וּסְפֹר֙ הַכּ֣וֹכָבִ֔ים אִם־תּוּכַ֖ל לִסְפֹּ֣ר אֹתָ֑ם וַיֹּ֣אמֶר ל֔וֹ כֹּ֥ה יִהְיֶ֖ה זַרְעֶֽךָ׃ He took him outside and said, “Look toward heaven and count the stars, if you are able to count…

The First Festival of Light

Chanukah is often referred to as the Festival of Light(s). But it is not the first Festival of Light in the world, as the Talmud tells us.