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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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2answers
81 views

Doesn't the idea of the Tower of Babel prove the Flat Earth approach?

IIRC, the idea was to reach the skies, pass (somehow) the firmament and fight G-d above. That is only possible if G-d is right above the Earth, which suggests the Flat Earth worldview. If they knew ...
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1answer
90 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 ...
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1answer
65 views

Contradiction in G-d's creation of two big luminaries

Rashi on Ber 1.16 brings the Midrash's that explains that G-d created two equal luminaries at first and no stars: המארת הגדולים: שָׁוִים נִבְרְאוּ ... ואת הכוכבים: עַל יְדֵי שֶׁמִּעֵט אֶת ...
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3answers
160 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 ...
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1answer
123 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 ...
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2answers
144 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 ...
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0answers
26 views

Astronomical significance of the placement of the Altar and the Even Hashtiyah

I heard that traditionally the placements of the Altar and Even Hashtiyah (Kodesh Hakodashim) was chosen by G-d from the days of the Creation. Is there anything special and significant astronomically ...
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1answer
47 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 ...
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3answers
196 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, ...
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97 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 ...
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0answers
49 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). ...
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4answers
296 views

Rabbinical sources that support the Flat Earth view

While many people are busy looking for the slightest hints of the vast scientific knowledge possessed by our Sages, I've bumped into Rasa"G's interpretation of Sefer Hayetzirah 4,2 (c.900) (is there ...
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2answers
205 views

Sources for the Earth rotating round the sun

Are there any Jewish writings that suggest the Earth rotates around the sun and is not the center of the universe?
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0answers
77 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
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0answers
80 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?
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1answer
48 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 ...
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3answers
208 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 ...
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2answers
209 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 ...
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1answer
108 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 ...
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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. ...
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1answer
191 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 ...
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2answers
168 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?
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2answers
117 views

Is there lunar drift in the fixed Hebrew calendar?

It is known that there is a slight discrepancy in the average length of a year according to the Hebrew calendar and the average length of an astronomical solar year which causes a seasonal drift in ...
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0answers
271 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?
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5answers
7k 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.' ...
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2answers
215 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 ...
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0answers
532 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 ...
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1answer
303 views

Is there any evidence of time-zones in Talmud? (Tanaim and Amoraim only)

There are many verses in the Talmud, Midrash and Siddur that state that the sun and moon rise and set through gates in the firmament. This would imply that there are no time-zones. To this world view ...
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1answer
453 views

Solar Power on Shabbos

What's the deal with using solar power on Shabbos? Cooking is permitted, but what of the following cases: 1) Heating water (Dud-Shemesh style) 2) Solar-powered watches 3) Solar-powered toys What ...
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1answer
196 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 later periods there were no explicit attacks on heliocentrism, although some Rabbis were not ...
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1answer
91 views

Are star stickers mutar?

Do any contemporary poskim discuss the usage of star stickers with regard to the prohibition of depicting celestial bodies (e.g. the glow-in-the-dark ones people put on walls and ceilings)? What if ...
14
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1answer
540 views

We're not supposed to point at stars?

I'm an Israeli Jew living in Israel. I often give "sky tours" where I show children and adults different stars and a view through a powerful binocular at objects of interest. Recently a young boy ...
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2answers
4k views

What time is sunset?

Is sunset (Shkiya) the time the sun hits the horizon or when it sunk completely below it? What about sunrise?
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4answers
327 views

How accurate is the Molad?

To the best of my knowledge the Molad is every 29.5 days + 793 Chalakim. Is there any information showing if the current Molad calculation is accurate scientifically? If it is off by how much is it ...
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3answers
204 views

Depicting a constellation

Assuming the intention is at least partly for educational purposes, Is it mutar to arrange star stickers in the form of actual constellations (say, on a ceiling) or is that included in the prohibition ...
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1answer
92 views

Where does Rashi say that Jews will be revered for knowledge of astronomy?

I remember reading a Rashi that says that the Jews will be revered for their knowledge of the stars. What's the location of this Rashi?
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1answer
102 views

Does the verse in Tehillim 147:4 imply that one cannot name a star after a person?

Usually, around Mother's Day and Valentines Day, I hear a radio commercial suggesting that, as a gift to your loved one, you can name a star after him / her. (Amazing gimmick - no inventory!!) In ...
9
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4answers
279 views

Why did Hashem create the world in such a way that a leap year is needed?

I understand why we have a leap year; to keep the sun and moon cycles in sync, so that Pessach is always in the spring. That's all technical, as a result of the moon orbiting too slowly - or the sun ...
5
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1answer
86 views

Counting years according to the solar calendar

I once heard there is an opinion in Rishonim (maybe Gaonim?) that says we count ones years of life according to the solar calender. So for example a boy would become bar mitzvah when he would turn 13 ...
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3answers
1k views

What does “shachar” in “alos hashachar” mean?

We find a number of terms referring to when morning starts and then perhaps a similar term used to refer to the time of shachris. Alos HaShachar (עלות השחר) Ayeles HaShachar (אילת השחר) and Shacharis ...
9
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1answer
520 views

What b'racha do you say on seeing the Aurora Borealis (if any)?

If one is so lucky as to see the Aurora Borealis (northern lights) or its southern equivalent, does one say a b'racha? If so which one? I've heard that oseh ma'aseh v'reishit applies to comets and ...
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4answers
459 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?
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2answers
218 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 ...
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3answers
394 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.
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4answers
2k views

How many stars did Rashi think there were?

According to the Chabad translation, Rashi on Deut. 1:10 implies that there are more than 600,000 stars: The Lord, your God, has multiplied you, and behold, you are today as the stars of the ...
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1answer
100 views

Can one say the b'rocho of borai meorai hoeash on stars

On motsai shabbos we make havdala and also make a b'rocho borai morai hoeish on what is called today the havdala. If one does not have one and no means of making a 'light' can one make the b'rocho on ...
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3answers
295 views

Significance of number 613 regarding the mitzvot

According to the Talmud (Makos 23b) "Moshe received 613 Mitzvos. They are 365 Lavim (negative commandments), corresponding to the days of the (solar) year, and 248 Mitzvos Aseh (positive commandments),...
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3answers
1k 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 [...
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1answer
243 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 ...
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4answers
164 views

How to care about the molad

I have read the great answers to Purpose of announcing Molad and understood that the halakhic reason to know the molad is to know what the Sanhedrin would know when they declared a new month. But ...