Questions tagged [astronomy]

The study of celestial objects and phenomena outside of the Earth's atmosphere.

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Has anyone explored Ptolemy's epicycles as an early form of Fourier analysis?

Whilst researching science in the ancient world, I came across an observation, which unfortunately I did not make a note of, and so cannot credit, that Ptolemy's epicycles were an early form of ...
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How did Hertzsprung-Russell diagrams end up so confusing?

HR diagrams show in which of several sequences individual stars fall, each respecting the rough principle that hotter stars are of higher luminosity. (Sequences other than the main sequence may bend ...
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What did the ancient Greeks know about the solar system, and how?

I'm aware that it was known to the ancient Greeks that the planets were somehow different from the stars. But in what depth did they know the solar system? In particular, did they know: that the sun ...
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How critical were Tycho Brahe’s accurate observations?

I am speculating about the value of Tycho Brahe’s - for his time - accurate observations and Kepler’s calculations. Might it have been possible for Kepler to formulate his laws based on Ptolemy’s ...
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Who was the first to state that scientific theories could be used to make predictions?

It seems to me that very few if any scientists/philosophers stated that science could be used for predictions before the early 1900s. In the scientific context I have only encountered the use of the ...
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How did Khayyam calculate the year so accurately?

Regarding the Islamic mathematician and astronomer Omar Khayyam, known (among other things) for his accurate calculation of the year, quoted from https://www.famousscientists.org/omar-khayyam/ ...
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In which year, people found that sun is not the only star in the universe? [duplicate]

It is a well-known fact now that the sun is one of the multiple stars in the universe. But in which year people at least hypothesized the fact that we are living in a universe with multiple stars?
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History of: Galaxy rotation rate estimates

Out of sheer curiosity: When was the first discovery/estimate of the rotation rate of our Galaxy? (To my understanding: in astronomy the angular velocity of the Solar System with respect to the Milky ...
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Was Herschel ever inspired to write music through his astronomy research?

While it is known that William Herschel was both a composer and an astronomer, could it be that he ever wrote music based on astronomy, or how he felt his research was proceeding? Just as Beethoven ...
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106 views

What astronomy efforts required multiplication of large numbers around 1600?

I'm reading an article about the history of logarithms and it says: One problem that was plaguing people at the time, especially astronomers, was arithmetic. Astronomical calculations required the ...
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How large were the differences in the orbit of Uranus which led to the calculation of the existence of Neptune?

After Uranus was discovered and its orbit calculated, its future orbit was calculated, and its future positions as seen from Earth were calculated. And observers of Uranus began to notice that Uranus ...
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Literature on Mayan mathematics

I asked this question on math.se and they sent me here. It is well known that Mayan people used vigesimal (base 20) numeral system, and had had an advanced calendar system. Except for these facts, I'...
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Laplace's Treatise of celestial mechanics

I am interested in nineteenth-century astronomy and Laplace's Treatise of celestial mechanics is often mentioned as one of the most significant contributions to science in this period. The more than ...
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Were epicycloids from astronomy acceptable curves in Greek geometry?

My simplified historical understanding is as follows. Euclidean geometry accepted a limited number of geometrical objects (straight-edge and compass constructions, conics). Descartes' Géométrie ...
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Did Ptolemy and other Greek scientists actually measure the distance to the Sun?

According to Subhash C. Kak: Early Theories on the Distance to the Sun: “Pancavimsa Brahmana states that the heavens are 1000 earth diameters, de, away from the earth. The sun was also taken to be ...
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Historical accounts of a oft-cited quip by astronomer Walter Baade

I am looking for any documented, historical reference to an oft-cited humorous reply by German astronomer Walter Baade (1893 – 1960). After having asked if other astronomers were familliar with the ...
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What made Newton realize that the law of gravitation was 'universal'? [duplicate]

Newton's law of gravitation operative near the earth is the same law causes the earth and the other planets to go around the sun and other heavenly phenomena. Was it a giant leap of faith by Newton or ...
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Did pre-Galilean astronomy inspire Mach's principle?

Was Mach, in his formulation of "Mach's principle," influenced by pre-Galilean astronomy, such as that of Aristotle in On the Heavens, where heavenly bodies influence terrestrial ones?
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What is the historical basis for the length of a sidereal year?

It is understandable that the length of a solar year can be found out using the time of solstices. But how did they find the length of a year with respect to the stars?
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Was the width of the Atlantic first determined in 1584?

In Eclipse: Journeys to the Dark Side of the Moon by Frank Close, it is stated that the 1584 lunar eclipse was used to determine the width of the Atlantic, by measuring the times in London and in ...
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Why do we call Tycho Brahe by his first name?

Why do we use the fist name in Tychonic system or Tycho's comet of 1577, instead of using the last name of Tycho Brahe? For comparison, we have the Ptolemaic system and the Copernican system. I am ...
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Who first reported the Crab pulsar's pulsing but was dismissed by an astronomer?

This answer to Has great eyesight been necessary for astronomers? mentions Astronomer Jocelyn Bell Burnell's recounting of a likely first visual observation of a pulsar. This can be found for example ...
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Mention of the fact Sun never rises or sets

Now-a-days it is well known that sun never rise or set but appears to human The sun stays in its position at the center of our solar system. It doesn't rise and set. But it appears to rise and ...
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When was the first quarter first used for moon phase?

For this doesn't make sense - we see one half of moon, not one quarter (at least compared to full moon).
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What were the applications of conic sections before Kepler?

When recently asked for a practical application of parabolas, I responded by talking about objects in free-fall. Afterwards as I was re-thinking this conversation it occurred to me that an object in ...
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Thomas Kuhn and the Relationship between Astronomy and Cosmology

In The Copernican Revolution, Thomas Kuhn states that "...only the Western civilizations which descend from Hellenic Greece have paid much attention to the appearance of the heavens in arriving at [...
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How were sundials first divided up into hour-long segments?

Even with present-day knowledge of celestial mechanics, if you asked me to go outside and set up a sundial without the aid of any other timekeeping devices, I would have a very hard time. The time ...
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What was the “libration of Pallas” that Gauss studied, when Pallas is not a moon of Jupiter?

This question is a request for general explanation of an astronomical phenomenon known as "Pallas libration", and isn't much about the details of Gauss's mathematical model of this libration. As is ...
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On Trigonometric Methods Available to Aristarchus

Approximately 2300 years ago, Aristarchus proposed a method for determining the relative distances of the sun and the moon in relation to the earth. Specifically, he asserted that when the moon is in ...
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Does Heliocentrism predate Copernicus?

I have seen this mentioned on the interwebs a few times. people have mentioned that some Greek thinkers and Islamic astronomers came up with heliocentrism before Copernicus and that Copernicus copied ...
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Several questions about Gauss's contributions to observational astronomy

I just want to check if anyone has additional information about a private astronomical research begun by Gauss in 1819, which dealt with the "movements of the solar system" in the galaxy (motion of ...
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Who were the other European astronomers who identified new stars around the time of Tycho Brahe?

Wikipedia notes: Early European astronomers such as Tycho Brahe identified new stars in the night sky (later termed novae), suggesting that the heavens were not immutable. Who were the other ...
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How has the estimate of the number of stars in the universe changed over time?

Current estimates for the number of stars in the universe are about 10^22. However, that number has changed several times as new observations have come forth. How has the estimate of the number of ...
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Notable theories on the far side of the moon pre 1959

On October 7th 1959, the soviet Luna 3 probe took the first picture of the far side of the moon. It has been known since ancient times that the moon was a sphere. It would have doubtless been ...
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Did knowledge of astronomy spread among Indo-European civilizations in antiquity?

Early civilizations of india, Greece, Babylon, China and Egypt have progressed in astronomy. Is there any shared knowledge among them and if any how can we find out?
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What is the origin of Zodiac (Kaalachakra) signs?

I think that The Zodiacal signs are of Vedic origin. Hindus, Greeks and Sumerians all have Zodiacal signs. Which is the most likely origin? The middle ring is the zodiac in the same between India and ...
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Where did Ptolemy compare the Earth to the distance of fixed stars?

I read the following in C. S. Lewis, Miracles (page 77-8) The immensity of the universe is not a recent discovery. More than seventeen hundred years ago Ptolemy taught that in relation to the ...
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Apparent contradiction in Copernicus' Commentariolus

There seems to be a contradiction in the assumptions that Copernicus makes when attempting to explain the motion of the planets: http://dbanach.com/copernicus-commentarilous.htm Assumptions 1 and 3 ...
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How did Cassini measure the “Cassini state” of the Moon? What measurements were made; what did the data look like?

The Phys.org article Physicists provide first model of moon's rotational dynamics, accounting for the solid inner core describes the September 2018 paper by Christopher Stys and Mathieu Dumberry The ...
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Where to find some early discussions of the Equinox(es)?

Said quickly, solstices are rather perceptible while the equinox is a mental construction. Archeoastronomical evidence shows that neolithic people already had knowledge about the solsticial points on ...
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What calculation did Halley or anyone else do to estimate the effects of Jupiter and Saturn on Halley's comet's return in 1758/9?

This answer to the question First observation that the movement of a planet or asteroid in its orbit was affected by another planet says: In 1705, with the mathematical assistance of Issac Newton, ...
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When did the research field of Astrophysics begin?

I have this vague idea that Astrophysics morphed out of Astronomy as a field of study and research. I am curious if this is true and when did Astrophysics become separate from Astronomy as a field of ...
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How did Eratosthenes determine that Alexandria and Syene were on the same meridian?

As discussed over here, Eratosthenes measured the earth’s circumference by comparing shadows cast at apparent noon at two locations separated by a known distance. Although accounts of the event (like ...
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What's the relationship between Aristotle's theory of elements and motion and geometry?

I'm having a hard time gathering my thoughts about this. I'm trying to find a connection or some sort of relation between the first 3 axioms (postulates) of Euclidean geometry (though around Aristotle'...
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Was Newton's successful calculation of precession of equinoxes a fluke?

I have looked at several sources, and Newton was right about the fact that the Earth is not a perfect sphere, but an ellipsoid caused the precession of equinoxes, as the Moon's gravitational ...
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Who correctly first explained the reason why you can see certain constellations only in certain seasons?

Of course, only heliocentric model can explain this. But, was this Copernicus himself or Galilei?
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Precision of Ancient/Medieval Astronomy (wrt Eclipses)

Today we can predict lunar/solar eclipses down to the precision of seconds.[1] But what was the precision like in medieval times? I imagine it must have improved over centuries. To keep the question ...
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Who first solved the two-body problem in 3D?

Who first solved the two-body problem in 3-dimensions? Was it Laplace?
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Could someone have discovered the moons of Jupiter before Galileo?

As Hans Lipperperhey had made a decent telescope albeit worse telescope before Galileo, source, would he have been able to theoretically view the moons of Jupiter before Galileo if he had looked?
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Sphericity of Earth from lunar eclipses - is Aristotle's argument valid?

Aristotle is often credited with proving the sphericity of Earth from the fact that the shadow of the Earth on the moon during lunar eclipses is always an arc of a round circle (as opposed to arcs of ...