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Questions tagged [astronomy]

The study or observation of objects or phenomena outside the Earth, including the Sun, Moon, planets, and stars.

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10 votes
4 answers
840 views

Why make a bracha on an earthquake but not on an eclipse?

According to this page, Chaza"l intentionally omitted solar and lunar eclipses from the list of natural phenomena upon which we make a bracha. The following explanation is given: The Hebrew term ...
10 votes
6 answers
13k views

What is the firmament?

In Genesis 1:6-8 the firmament and its creation are mentioned for the first time: And God said: 'Let there be a firmament in the midst of the waters, and let it divide the waters from the waters.' ...
1 vote
1 answer
149 views

Permissibility of digital art of celestial bodies

According to Halacha, for Jews, there is a prohibition of portraying Celestial bodies in art, even if not for idolatry. (Generally, for noahides there is some concern, but the rules for what might be ...
1 vote
0 answers
118 views

Meaning / Significance of the Ring on planet Saturn

Shabbos and the planet Saturn are linked. I was wondering if anyone has a source for the ring(s) on the planet Saturn being a wedding between the Jews / Shabbos / Hashem? I heard this idea before but ...
9 votes
2 answers
314 views

Is there any evidence that Chazal knew what caused eclipses?

Many ancient cultures believed that eclipses are caused by things other than syzygy. The Egyptians had Apophis. The Hindus had Rahu. (The interested reader can see more here.) In light (ha) of the ...
2 votes
0 answers
76 views

Do Zmanim follow the city, or the Gavra?

Are halachic times for prayer, comencing Shabbos, ect. calculated according to a persons exact location or is there one "time-zone" for the entire city? And if yes, how would this apply for ...
4 votes
1 answer
475 views

Sukkos 2a ~ Reality shows the need for 13-אמות while the Gemara states that the smallest Sukkah is enough?

ר׳ זירא says that a Sukkah that is lower than 20-אמות, the סכך is the one blocking the sun and creating the shadow, not the walls, and therefore the Sukkah is kosher, like it says in the פסוק ״וסוכה ...
0 votes
2 answers
139 views

Why are the planets so different from each other?

In Rambam's (originally Aristotelian) view the planets are heavenly bodies made of some magical crystal-like substance (i.e. Foundations_of_the_Torah.3.1). After we examined some of them, they turned ...
1 vote
0 answers
90 views

What rabbis did explicitly deal with Heliocentrism (accepted or rejected)?

Following the closed question "whats-the-earliest-acknowledgment-of-heliocentrism", I'm looking for any rabbinic sources that explicitly deal with heliocentrism.
0 votes
1 answer
422 views

What's the earliest acknowledgement of Heliocentrism in Judaism? [closed]

The English Wikipedia says that Heliocentrism was "official" in Judaism only by the 20th century: "In the 19th century, ... Hatam Sofer (d.1839) gave approbations to two books even ...
-6 votes
4 answers
2k views

What additional Rabbinic sources support the Flat Earth?

Rasa"G's interpretation of Sefer Hayetzirah 4,2 (c.900CE): "העולם ככפה, והגלגל אינו זז ממקומו...: (the world is like a dome and the sphere [of stars] does not move). Are there other ...
3 votes
2 answers
142 views

Measuring Moon's elevation in units of length

Rosh Hashanah 24a: The Sages taught in a baraita: If one witness says that he saw the moon two plow handles high above the horizon, and the other one says it was three plow handles high, their ...
0 votes
2 answers
245 views

Why does plant life come after the earth, waters and the firmament, but before the planets?

This question only addresses the blueprint of the creation as described in the first chapter of Bereshit. It does not address the sequence of the actual creation, as described in Bereshit 2, or the ...
0 votes
3 answers
1k views

When did Hashem stop the sun?

As in the time of Milchemes Ay, Hashem stopped the sun for 36 hours. Where else in Tanach did it happen? I need more then one.
3 votes
1 answer
112 views

Meaning of Monen in Kabbalah

I came across the term "monen" but have been unable to find much information on it in scholarly or scriptural sources. The main information online appears to be a kabbalah-related stub on ...
0 votes
2 answers
1k views

What is the relation between the month Nisan and the spring equinox?

I'm searching for the relation between Nisan and the spring equinox according to Scripture. I know of the texts Genesis 1:14, Exodus 12:2-3, Leviticus 23:15 and Deuteronomy 16:1. I find multiple ...
4 votes
4 answers
409 views

Photographing an Eclipse

There is a general prohibition on depicting and/or owning depictions of celestial bodies, such as the sun and moon (see, e.g., the Rambam Hilkhoth Avoda Zara 3:18). Nonetheless, there are opinions ...
3 votes
1 answer
353 views

Aurora Borealis in Midrashim

We see many fascinating works of Hashem around the world and one of which is Aurora Borealis. Do our midrashim or books on mysticism have anything to say about its origin or anything related to it?
2 votes
0 answers
75 views

A beracha on the "Great conjunction"?

Tonight (or earlier tonight in Israel) the planets Jupiter and Saturn come so close that one might think that they are a single star. Is this occasion to say the beracha of עושה מעשה בראשית? It is not ...
4 votes
1 answer
416 views

How to observe Shabbat on Mars

Inspired by this question. The Martian day is 24 hours, 37 minutes long. After approximately 39 Martian days, 40 days have passed on Earth. As a Martian colonist, should I rest every seventh Martian ...
4 votes
3 answers
1k views

Sources for the Earth revolving round the sun

Are there any Jewish writings that suggest the Earth revolves around the sun and is not the center of the universe?
9 votes
2 answers
1k views

Minhag not to view moon through a window?

I have a vague memory of being told not to gaze at the moon through the glass of a window. I think it had something to do with kabbalah. I know it's permitted to say kiddush levanah by looking at the ...
2 votes
3 answers
2k views

Biblical description of the firmament vs. round earth in the Zohar

Zohar Vaikra 10a [quotes the Book or Rabbi Hamnunab Sabah]: וּבְסִפְרָא דְּרַב הַמְנוּנָא סָבָא, פָּרִישׁ יַתִּיר, דְּהָא כָּל יִשׁוּבָא מִתְגַּלְגְּלָא בְּעִגוּלָא כַּכַּדּוּר, אִלֵּין לְתַתָּא, ...
1 vote
1 answer
138 views

How can constant creation of new stars explained theologically?

"... we get on average about one new star per year, and one star dying each year as a planetary nebula in the Milky Way.... therefore there are about 275 million [born] per day, in the whole ...
4 votes
3 answers
574 views

Stars are living creatures?

the Rambam in yesodei torah says that stars are creatures with intellect. how do we reconcile this with modern science which says that they are merely inanimate balls of hydrogen and helium gas.
1 vote
3 answers
288 views

Has the number of the tribes of Israel anything to do with the universe/stars/planets?

Has the number of the tribes of Israel anything to do with the universe/stars/planets? Maybe the other way around? Is there anywhere in the Talmud or tradition that talks about this question (not ...
-1 votes
2 answers
240 views

Why did Hashem create only one planet (Earth) in the whole entire universe that can support intelligent life

Is there any rabbinic literature explaining why Hashem created only one planet (Earth) in the whole entire universe that can support intelligent life?
6 votes
1 answer
320 views

Source for Seforno that the Earth was tilted at the time of the Flood

In Oorah's 2009 Shmorg video, one of the tracks is about Birchat Hachama, and at around the 10 minute mark, the narrator states the following (I'm paraphrasing): The Sforno writes that before the ...
9 votes
3 answers
2k views

Is the midrash about the moon and sun being the same size intended literally?

The Rambam in his introduction to perek Chelek discusses midrashic literalist, and classifies different approaches of different groups to midrash. He writes: You should know that as to [...
-2 votes
2 answers
234 views

Why did G-d create the Earth spherical?

I hope nobody questions the fact of the spherical Earth. Just as spherical as all other celestial bodies. Many argued whether we knew this fact or not, but I don't recall that those who claim we ...
-4 votes
1 answer
149 views

Why did G-d create everything important off-center?

I hope not to argue that the Heliocentric view is true as is our current understanding of [our position in] the Universe, the Earth is rotating around the Sun, that is rotating around the center of ...
2 votes
0 answers
522 views

Shooting Stars and Luck

There seems to be a non-Jewish association of good luck with seeing a shooting star. Is there any source for this in Judaism?
1 vote
1 answer
75 views

How precise were the Temples' directions (East/North)

Calculating the true astronomical North/South is very simple - find the longest way and cast a shadow. Are there sources on how precise those directions in the Temples were? Are there special Jewish ...
4 votes
0 answers
187 views

How do the outer planets: Uranus, Neptune and Pluto fit into Judaism?

It is not a secret that we discover new things in all fields of science, not mentioned in our sources all the time. We know that in Judaism the 7 planets represent/aligned with 7 spiritual forces and ...
1 vote
0 answers
78 views

Does Judaism differentiate between a planet and a star?

On the 4th day, G-d created Sun, Moon and the stars. Besides the Moon, Mercury, Venus, Mars, Jupiter, and Saturn were known since ancient times (not mentioning the existence of the real stars). ...
7 votes
1 answer
283 views

Aruch Hashulchan's moon-distance estimate

Aruch Hashulchan (1829–1908), Orach Chayim 397:1, says that a מיל is the same as a Russian верста (verst) or 500 сажен (sazhen), which comes to 1066.8 meters. In 426:2, he says the distance to the ...
6 votes
1 answer
388 views

Levana or Yareach?

In the entire Tanach the moon is generally called Yareach. There are 3 instances where it is called Levana: 1) ישעיהו: כד. כג. וחפרה הלבנה ובושה החמה 2) ישעיהו: ל. כו. והיה אור הלבנה כאור ...
15 votes
5 answers
1k views

Permissibility of images of celestial bodies

There is precedent in halachah that one may not create images of celestial bodies such as the moon and stars; see here for background. This is derived in the Gemara from the pasuk "Do not make [images ...
2 votes
0 answers
119 views

For the start of the day, is "sunset" astronomical or visible?

Yesterday was the equinox and I noticed that the day was longer than 12 hours according to the (secular) sunrise/sunset times. Curious, I did some investigation. One reason for the difference is how ...
2 votes
0 answers
88 views

Keeping Two-day Shabbos in the Pacific Islands? [duplicate]

What's this I see about people in the Pacific Islands keeping two days of Shabbos? If it is true: Who, how, since when, and why?
18 votes
2 answers
3k views

What Blessing Does One Make on a Solar Eclipse?

What Blessing Does One Make on a Solar Eclipse? I will be in Nevada next week and would like to make a blessing over the May 21 Solar Eclipse. Thanks!
4 votes
2 answers
305 views

Conservative Kiddush Levanah

The version of Kiddush Levanah printed in the Conservative movement's siddur omits the verse "כשם שאני רוקד כנגדך..." I've heard that this is because the Conservative movement believes that in an age ...
5 votes
2 answers
414 views

Illustrated hilchot Kiddush Hachodesh

I remember seeing about 20 years ago a beautiful annotated commentary on Rambam's hilchos kiddush hachodesh, with extensive illustrations and calculations, explained according to both ancient and ...
12 votes
4 answers
986 views

Plants before the Sun in the Order of Creation

Why does plant life precede the Sun in the order of creation given that plants need the Sun to do photosynthesis?
1 vote
1 answer
151 views

Counting and naming the stars

Why does Hashem count and name the stars in Heaven? This is mentioned in the first Rashi on Shemot, see below. I would like an explanation on this... Quote from Rashi: And these are the names of the ...
18 votes
7 answers
1k views

How did the moon shrink?

The Bavli, Chulin 60:2, says (in my own loose translation): Rabbi Shim'on ben Pazi noted a contradiction: [B'reshis 1:16] says, "God made the two big luminaries" and "the big luminary… ...
0 votes
1 answer
159 views

Parameters of the bad omen for eclipses

The Gemara in Succah 29a says that solar eclipses are bad omens for the nations, while lunar eclipses are bad omens for the Jews. The Gemara compares an eclipse to a king who leaves his guests sitting ...
4 votes
2 answers
298 views

Good and Bad Omen - on something that can be calculated in advance

Inspired by Why make a bracha on an earthquake but not on an eclipse? When something can be predicted in advance to an exact moment - for example an eclipse which Chazal say it is a bad Omen (Sukkah ...
2 votes
0 answers
38 views

The moon in the future [duplicate]

We say in Kiddush Levanah, יהי רצון מלפניך...למלאת פגימת הלבנה ולא יהיה בה שום מיעוט May it be Your will...to fill the reduction of the moon, and that there should be no diminishment in it. ...
5 votes
0 answers
1k views

Minyan, netz hachamoh, and precision in time

There are halachic sources that discuss the importance of davening shemona esrei at netz (at sunrise), some of which state that it is preferable to daven at netz over davening with a minyan (at least ...