Questions tagged [history]

Questions regarding the history of astronomy, including discoveries and scientists.

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15
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3answers
2k views

Was lunar libration first observed or first predicted? In either case, who was the responsible party?

How old is the idea of the far side of the Moon? got me thinking that as soon as we see the moon librate we have to come to terms with there being even more of it we can't see. The Moon's libration is ...
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1answer
225 views

How old is the idea of the far side of the Moon?

The far side of the Moon is the side which always faces away from the Earth, due to tidal locking. Due to libration, about 18% of this far side can be seen at one point or another through telescopes. ...
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1answer
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How was the speed of the Sun around the Milky Way Galaxy calculated?

The Sun travels around the Milky Way Galaxy with a speed of 220 km/s. The question is: where did this value come from? Is there any article about the calculation?
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1answer
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What does 's' or 'ds' or $ds^2$ mean in the Schwarzschild equation(s)? [closed]

And: These are from Wikipedia on Schwarzschild metric, Derivation of the Schwarzschild metric and the last is from Science Direct, Schwarzschild metric.
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1answer
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What do "P" and "F" mean in the compass legend of Carrington's sunspot drawing?

In Richard Carrington's drawing of sunspots, he has a compass labeled "N", "P", "S", and "F". If "N" is North and "S" is South, what do &...
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How exactly was Giovanni Cassini able to measure the distance to Mars?

Recently learned that Cassini was able to calculate the distance to Mars quite well using parallax in 1671. I was surprised, since even at opposition of Mars, the parallax (with respect to the Earth's ...
2
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2answers
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Why does the difference between terrestrial times and universal time, $\Delta T$, have such a strange behaviour?

I was reading about ancient astronomy, and one of the main phenomena described is eclipses. Now, I read this 2016 paper by Stephenson, Morrison and Hohenkerk, in which they determine the values of the ...
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2answers
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Was the Nobel prize for gravitational waves handed out based on a hand-drawn theoretical curve? Has the data been fit more rigorously now?

In Sabine Hossenfelder's November 2019 video "Have we really measured gravitational waves?" (transcript, video), Sabine mentions the now famous image of the generally agreed-upon-to-be-very-...
3
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0answers
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Did a watch company really try to sue radio astronomers for using the word "pulsar"? If so, which astronomers?

After about 48:37 in the really wonderful video Jocelyn Bell Burnell Special Public Lecture: The Discovery of Pulsars (linked below) Dr. Bell Burnell describes the ...
5
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1answer
596 views

What two "little observatories" run by a university in Chile and "by Germans" are near the future site of the Extremely Large Observatory?

Brady Haran is known for the Numberphile and Periodic Table of Videos YouTube channels but also does Deep Sky Videos. In the video for the Extremely Large Telescope Haran stands at the site of the ...
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How was Theia discovered?

The Moon might have been created by the impact between the Earth and a Mars-sized body named Theia. Theia no longer exists, so when and how was it discovered? What clues led to the Theia hypothesis? ...
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Are there any old/ancient star maps that we can compare to today’s and see drastic differences?

Stars move through the sky very slowly, which is not noticeable in a human lifespan. I’m aware of proper motion of Barnard's Star and things of the sort but I’d like to obtain a noticeable record of ...
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1answer
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Which A. M. Fridman is the author of this paper on gravitational stability?

Is this paper on globular cluster stability still up to date? links to The Stability of Globular Clusters and Spherical Galaxies. by A. M. Fridman of the: Institude of Nuclear Physics, Siberian ...
2
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1answer
81 views

How did the measured diameter of Ceres evolve over time?

Based on the Wikipedia page of Ceres, Herschel measured a diameter of 260 kilometers for Ceres, and Schröter measured 2613 kilometers. I do remember seeing at least a half-dozen estimates of the ...
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1answer
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Why did the famous Multiple Mirror Telescope (MMT) get rid of them and become the Massive Monolithic Telescope?

Popular Science's 2016 article The silliest names scientists have given very serious telescopes... Ranked! says: Arizona’s MMT Observatory used to house the Multiple Mirror Telescope. In 1998, ...
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When was H-alpha first used to observe the universe?

The H-alpha line is used by astronomers to trace the presence of hydrogen in galaxies or to view protuberances on the Sun. When was the H-alpha emission of astronomical objects such as galaxies first ...
7
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1answer
234 views

How long was the HST initially supposed to work?

For space missions, there is typically a minimum time that is defined for the mission to fulfill all of its science objectives, then an extended mission with extra objectives. And after that, the ...
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1answer
44 views

Why is the FLRW universe (general relativity solution(s)) sometimes called the 'FRW universe'?

Why is the letter L for Georges LeMaîtres often, or even usually, left out? Does he, or does he not, deserve some credit for this cosmological solution to Einstein's general relativity?
22
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1answer
3k views

Why was there a gap in the number of asteroid detections between 1807 and 1845?

The first asteroid, Ceres, was discovered in 1801, although it wasn't called an asteroid yet. Pallas, Juno and Vesta were discovered shortly after. Then no new asteroids were discovered for 38 years, ...
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2answers
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Did Cassini return a photo of Saturn's rings shown from closer to Saturn?

A quote from a book, Perelandra by C.S. Lewis: "no eye looked up from beneath on the Ring of Lurga"; now Lurga is Saturn, and no human eye has been to Saturn, let alone at a lower altitude ...
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4answers
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How did Astronomers mostly(?) agree to publish arXiv preprints along with peer-reviewed Journals? Was there pushback?

This excellent, thorough and well-sourced answer to Has a gravitational microlensing event ever been predicted? If so, has it been observed? includes four links to papers on adsabs.harvard.edu pages, ...
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1answer
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What is the mnemonic reason behind b being galactic latitude? (in the Galactic Coordinates frame)

I'm not sure if this is a question that has been posted before, and I'm also not sure if the answer is really mnemonic. If that's the case, I'd like to understand why we assigned $b$ to latitude ...
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2answers
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Was Newton the first to mention the orbital barycenter?

A barycenter is the common center of mass of an orbiting system. Here is a illustrative gif from wikipedia: The first mention of something like a barycenter that I could find is in a translation of ...
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Equivalence of minor epicycle and eccentric

In epicycle-deferent astronomy, adding a second ”minor” epicycle to account for observational discrepancies is observationally equivalent to shifting the deferent into a so-called eccentric, or a ...
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1answer
93 views

On Augustus' Actual Prescription to Restore the Julian Calendar to Accuracy

I hope that I may ask this question here as I have seen some favorably received questions related to the Julian calendar on this site. From James Evans' book, ``The History and Practice of Ancient ...
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Statistics of the purposes of archeoastronomical sites?

Archeoastronomy can be defined as the interdisciplinary or multidisciplinary study of how people in the past "have understood the phenomena in the sky, how they used these phenomena and what ...
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1answer
68 views

Historical estimates of the density parameter

From the reference in this answer I learned that our current estimate for the density parameter (i.e., the density of the universe divided by the critical density, which determines the shape of the ...
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1answer
114 views

Since when do astronomers have the notion that space is void? [duplicate]

Since when do astronomers have conjectured that space is void, and not full of air like our immediate environment? I am more interested about how long the notion has been around and how influential ...
8
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1answer
102 views

Mercury's spin-orbit resonance

When was it confirmed that Mercury has a 3:2 spin-orbit resonance and by whom (research group/radio observations...)? The first suggestion was made by Giuseppe Colombo in 1965. Its proximity to the ...
5
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1answer
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Ptolemy’s understanding of the planet’s whereabouts

I imagine that Ptolemy’s epicycles were performed as real circles - around equants - in two dimensions, e.g that he was able not only to give the angles to planets and the Sun as seen from the Earth, ...
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1answer
91 views

What happened to the 2017 proposal on redefining planethood? Is this information available?

In 2017, Alan Stern et al. submitted a geophysical planet definition to the IAU for review which states “A planet is a sub-stellar mass body that has never undergone nuclear fusion and that has ...
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1answer
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Researching mechanics without “fixed stars”

In the history of humanity, easily observable extra-(Solar System) objects greatly helped understanding certain phenomena inside the Solar System. Importantly, the “precession of the equinox”, and ...
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2answers
113 views

Why do astrologers use the “wrong” sign?

I realize this may be the wrong site for this question... I apologize if you consider it inappropriate but hope this community knows the answer. We just experienced the spectacular conjunction of ...
6
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1answer
185 views

When was it first determined that the Sun is a star?

Just looking at the sky, it is not at all obvious that the Sun is a star: stars are fixed on the celestial sphere, they are point-like and not very bright, whereas the sun is a big (compared to a star)...
2
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1answer
96 views

What other definitions for a planet were proposed?

This article from the IAU states The first draft proposal for the definition of a planet was debated vigorously by astronomers at the 2006 IAU General Assembly in Prague and a new version slowly took ...
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2answers
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What was the definition of a planet before August 24, 2006?

In 2006, the IAU produced a definition of what it is to be a planet. This definition famously excludes Pluto, to the disarray of this small body's fans. Before this decision, what was the definition ...
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0answers
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Angles in Ptolemaic Model

I am about to work with Ptolemy's Model for the motion of an upper Planet (Mars). I use a epicycle rolling on the deferent. As a first step, I am just interested in the shape of the trajectory, which ...
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2answers
194 views

How were the distances to stars measure before parallax?

A comment under When was the distance to a star measured for the first time without using parallax? mentions that the distance to stars was measured before parallax was possible. How was this done?
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2answers
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When was the distance to a star measured for the first time without using parallax?

This is somewhat of a follow-up to When was the parallax of a star first measured? Once the distance to the nearest stars was determined, it was possible to discover physical properties of stars (such ...
3
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1answer
123 views

What comet's tail did Earth pass through before Halley's?

This answer to Any record of the Earth passing through the tail (not trail) of a comet? mentions Earth passed through the tail of Halley's Comet in 1910. It caused a bit of a panic due to claims that ...
3
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0answers
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What were they expecting to see when Halley's comet appeared in 1910?

This answer to Any record of the Earth passing through the tail (not trail) of a comet? mentions Earth passed through the tail of Halley's Comet in 1910. It caused a bit of a panic due to claims that ...
4
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1answer
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Any record of the Earth passing through the tail (not trail) of a comet?

Discussion below the Space SE question How hard is it to fly through the tail of a comet? Has it been done? has led me to ask if there is any record of the Earth passing through the tail of a comet. ...
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1answer
233 views

What exactly is a Hamiltonian telescope? Is this one?

This comment on the current answer to Why is this telescope so short? How hard is it to make such a fast primary? says In this forum topic Borisov appears to call it an f/1.5 Hamiltonian. Wikipedia'...
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3answers
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Did the night sky ever change in recorded history?

I wonder whether there has ever been a major change of the firmament in recorded history, like changes in the positions of stars, changes in constellations, or stars disappearing after going supernova....
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2answers
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Why does the Simbad page "A.A. Michelson's Jovian Galilean-satellite interferometer" show data for Betelgeuse?

When searching for things related to How did Michelson measure the diameters of jupiter's moons using optical interferometry? I came across the ui.adsabs.harvard.edu entry A. A. Michelson's Jovian ...
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How did Michelson measure the diameters of jupiter's moons using optical interferometry?

In Betelgeuse: How its Diameter was measured (Chant, C. A., Journal of the Royal Astronomical Society of Canada, Vol. 15, p.133, Bibliographic Code: 1921JRASC..15..133C) the author says: The paper in ...
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1answer
156 views

When was the parallax of a star first measured?

Telescopes like Gaia measure the parallax of stars with a great precision. But for stars that are beyond 11 kpc, their parallax is still too small to be measured. With Earth-bound telescopes, only the ...
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2answers
75 views

Before the 1761 transit, what was our best estimate of the distance to the Sun?

In 1761, many expeditions were launched to determine the distance to the Sun using parallax during the transit of Venus. Prior to the 1761 transit, what was the best estimate for the Earth-Sun ...
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Records of Venus transits prior to 1761

Following the publication in 1716 of Edmond Halley's method to determine the solar parallax with the transit of Venus, many expeditions were launched to observe the 1761 transits. The following ...
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When was the variation of apparent diameter of the moon first measured?

The orbit of the Moon around the Earth isn't quite a circle. Since distance between the Earth and the Moon changes over time, the apparent diameter of the Moon also varies very slightly. With a ...

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