The mitzvah to study astronomy

Here’s a gemara that a YU physics graduate has no choice but to comment on, from Shabbat 75a:

אמר רב זוטרא בר טוביה אמר רב: המותח חוט של תפירה בשבת - חייב חטאת. והלומד דבר אחד מן המגוש - חייב מיתה, והיודע לחשב תקופות ומזלות ואינו חושב - אסור לספר הימנו. [...]

אמר רבי שמעון בן פזי אמר רבי יהושע בן לוי משום בר קפרא: כל היודע לחשב בתקופות ומזלות ואינו חושב - עליו הכתוב אומר +ישעיהו ה+ ואת פעל ה’ לא יביטו ומעשה ידיו לא ראו.

אמר רבי שמואל בר נחמני אמר רבי יוחנן: מנין שמצוה על האדם לחשב תקופות ומזלות - שנאמר +דברים ד+ ושמרתם ועשיתם כי היא חכמתכם ובינתכם לעיני העמים איזו חכמה ובינה שהיא לעיני העמים - הוי אומר זה חישוב תקופות ומזלות.

English from Soncino:

R. Zutra b. Tobiah said in Rab’s name: He who pulls the thread of a seam on the Sabbath is liable to a sin-offering; and he who learns a single thing from a Magian is worthy of death; and he who is able to calculate the cycles and planetary courses but does not, one may hold no conversation with him. [...]

R. Simeon b. Pazzi said in the name of R. Joshua b. Levi on the authority of Bar Kappara: He who knows how to calculate the cycles and planetary courses, but does not, of him Scripture saith, but they regard not the work of the Lord, neither have they considered the operation of his hands.

R. Samuel b. Nahmani said in R. Johanan’s name: How do we know that it is one’s duty to calculate the cycles and planetary courses? Because it is written, for this is your wisdom and understanding in the sight of the peoples: what wisdom and understanding is in the sight of the peoples? Say, that it is the science of cycles and planets.

The Semag actually records this as one of the 613 commandments, aseh 75:

Mistakes about science

Today's daf talks about spontaneously generated lice. There's a dispute among tannai'm whether you can kill a louse on Shabbat (Shabbat 12a, 107b). Rav Yosef explains that the disagreement only applies to insects that "do not reproduce," but killing all other insects is forbidden (107b). The rishonim then discuss which species of insect are generated from sweat, from rot, from dirt, etc., or from eggs. The halakhah concludes that killing lice is permitted.

There are much more dramatic Torah-versus-science issues out there than this one. If you're looking for explosive controversy, you want evolution. If you're looking for out-of-date science in the Talmud, this collection is just a start; Pesahim 94b is a big one in particular. If you're looking for a legal and moral mess, look into organ donation.

But, even if relatively undramatic, the issue of spontaneous generation is centrally important to science versus Halakhah. It's unique as a black-and-white case of a canonized halakhah based on rejected science.