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Questions tagged [history]

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

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19 votes
8 answers
10k views

How did the ancient cultures determine that the year was actually a fraction of an extra day beyond 365 days?

Google says the year is exactly 365.2422 days, and so they make a leap year every 4th year, but that ends up being 365.25 days per year on average. So every 100th year they don't have a leap year, but ...
Lance's user avatar
  • 431
2 votes
0 answers
54 views

How did Herschel determine the diameter of Mars?

The book The Planet Mars: A History of Observation and Discovery by William Sheehan states that Herschel calculated the diameter of Mars to be 0.55 times that of the Earth, and he found its figure to ...
usernumber's user avatar
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1 vote
1 answer
87 views

What is the explanation for discrepancies in RA values at Santa Maria Degli Angeli e dei Martiri in Rome

There is a meridian line in the floor of this church in Rome: http://www.santamariadegliangeliroma.it/paginamastersing.html?codice_url=La_Meridana& I took this photograph which shows the inlaid ...
Theo H's user avatar
  • 113
2 votes
2 answers
114 views

What exactly was "The curse of Sisyphus" and why did it take so long to find out about the radar detection of its companion?

This answer to First satellite of an asteroid (or double asteroid) ever imaged by delay-Doppler radar? mentions that Wikipedia's 1866 Sisyphus; Binary system says: In 1985, this object was detected ...
uhoh's user avatar
  • 30.8k
1 vote
1 answer
102 views

Ancient adjudication of the new moon from witness testimony

The ancient method of certifying the new moon in the Land of Israel in ancient times is described in Mishnah Rosh Hashanah 2:6. Witnesses would come to Jerusalem and testify before the Sanhedrin that ...
wberry's user avatar
  • 349
2 votes
2 answers
144 views

Since John Herschel was first to make a photograph on a glass plate in 1839, why was the first astronomical photograph not taken until 1840 by Draper?

Researching Who named "the 37 cluster" or at least made that name widely known via writing? I came across the Moneylink September, 9, 2020 article 9 September 1839: Sir John Herschel takes ...
uhoh's user avatar
  • 30.8k
2 votes
0 answers
62 views

Who named "the 37 cluster" or at least made that name widely known via writing?

The March 29, 2024 Veritasium video Why is this number everywhere? is about an apparent prevalence of the number 37 (for at least some people, including ) and in a montage of instances of 37 it shows &...
uhoh's user avatar
  • 30.8k
1 vote
0 answers
90 views

Kepler's description of lunar mountains before telescope

This question Why is the lunar relief not visible in photographs of solar eclipses? Reminds me of something that I remember that Johannes Kepler wrote. When telescopes discovered mountains and ...
M. A. Golding's user avatar
6 votes
1 answer
258 views

First photographic image taken with telescopes to produce astronomically useful results? What telescope was used?

comments on the question and answer(s) to What are the technological advancements that made it possible for modern large telescopes to work with alt-az mounts instead of equatorial mounts? have made ...
uhoh's user avatar
  • 30.8k
1 vote
1 answer
208 views

Why the ancient Greeks associated planets with gods?

They associated the Sun with Helios and the Moon with Selene, with the names of these gods also being used for these astronomical bodies. For other astronomical bodies, a name and an associated god ...
user avatar
3 votes
1 answer
262 views

κ₀ for Mercury—Formula (another definition)

Following my other question about a specific “hidden” formula in Ptolemy’s model for Mercury, I am now looking for yet another “hidden” formula, this time the one used to find $\bar\kappa_0$ so that $...
Pierre Paquette's user avatar
1 vote
1 answer
107 views

How was the size of the earth determined 100/200/300 years ago?

How was the size of the earth determined 100/200/300 years ago? I know that by then the had better methods then the simple sticks and shadow experiment.
blademan9999's user avatar
2 votes
2 answers
349 views

κ₀ for Mercury—Formula

I refer here to Ptolemy’s epicycle-and-deferent model of the Solar System, specifically that of Mercury (see drawing). In this model, Mercury (not shown) revolves on an epicycle of center C, which ...
Pierre Paquette's user avatar
16 votes
1 answer
3k views

How did the ancient Greeks measure celestial angles?

I'm reading about how Hipparchus measured the earth's precession; I basically understand the theory involved—you wait for a lunar eclipse, which allows you to infer the sun's position exactly, at ...
user326210's user avatar
1 vote
1 answer
244 views

Planets Named After Roman Gods, Except Earth

I’ve looked this up, but not necessarily sure the internet has the right answer. Why are the planets in our solar system named after Roman gods, except Earth, and why is only one of the nine planets ...
allthings27's user avatar
8 votes
1 answer
3k views

Why did the dust between the planets disappear during the birth of the solar system?

I'm catching up on my childhood mistakes. One of them was the "nuclear flash", the enormous explosion when the sun ignited. Apparently, this did not happen as the ignition of the sun was a ...
Dominique's user avatar
  • 445
1 vote
1 answer
84 views

Where can I get historical data of tropical longitude of Delta Cancri

I need historical data of tropical longitude of Delta Cancri. Where can I get it. As of now it is approximately 128 Deg from Vernal Equinox. Where can I get it's historical data, say from 5000 BC to ...
codingEnthu's user avatar
2 votes
1 answer
378 views

How did the temperature of the solar system evolve?

As a child, I've read that stars ignite during a so-called "nuclear flash". I understood this as a very violent outburst of energy from the sun, causing all dust between the protoplanets to ...
Dominique's user avatar
  • 445
4 votes
1 answer
187 views

Comet and eclipse

It seems likely the 12P/Pons-Brook comet will be visible at the same time as the 2024-04-08 American eclipse. How unusual is this and what can science say about what will appear? What other historical ...
David's user avatar
  • 337
2 votes
1 answer
111 views

is there any site with historical radiotelescope data about observations 21 cm line Hydrogen (1.42 GHz)?

I am looking for an open source that contain historical raw data or (meta)data about historical observations of the 21 cm line hydrogen made via radio telescopes.
Rad's user avatar
  • 21
3 votes
0 answers
148 views

When did astronomers accept that fixed stars aren't fixed and are at different distances?

Was it when heliocentric model was spreading in the whole world? I saw a model of the solar system that was made in the 18th century where the sun was in the middle and the planets and comets around ...
Mansur Hasan's user avatar
1 vote
1 answer
149 views

How did scientists decide the boundary of the Milky Way at Edwin Hubble times?

I know Edwin Hubble used Cepheid variables to prove the Andromeda Galaxy is not part of the Milky Way. But how did scientists at that time decide the boundary of the Milky Way? And how did they find ...
Qiulang's user avatar
  • 127
7 votes
1 answer
293 views

What did Galileo believe stars were?

Did he believe stars were attached to the sphere of fixed stars, or did he believe they were suns or did he believe stars weren't attached to anything but just points of light?
Mansur Hasan's user avatar
7 votes
2 answers
357 views

How plausible is it for legends about the Pleiades to be this ancient?

There's a tangent at the beginning of this video on the Epic of Gilgamesh briefly talking about an oddity where most ancient cultures have stories about the Pleiades star cluster, often describing ...
redroid's user avatar
  • 171
6 votes
1 answer
204 views

How did we figure out that Stars become red giants and when did we find out that they will?

I always hear that the Sun will be one but never when we found that out or how.
R-Obsessive's user avatar
14 votes
2 answers
1k views

What telescope is Polish astronomer Kazimierz Kordylewski holding in this April 1964 photo at the Jagiellonian University Observatory in Krakow?

The following questions touch on Kordylewski clouds Can dark matter accumulate at Lagrange points? Are dust-dust collisions necessary to explain Kordylewski clouds at Earth-Moon L4/5? Aren't the ...
uhoh's user avatar
  • 30.8k
10 votes
1 answer
3k views

Is the Sun hotter today, in terms of absolute temperature (i.e., NOT total luminosity), than it was in the distant past?

I am constantly reading that the Sun is at least 20% 'hotter', in terms of total radiation/luminosity, than it was a few million years after its formation (i.e., after the Hayashi stage...) But what ...
Kurt Hikes's user avatar
  • 5,167
31 votes
1 answer
6k views

Why did it take so long to invent telescopes given glass was used 4000 years ago in Mesopotamia?

Is a telescope difficult to make? Does glass have to be polished and shaped very precisely? Or is a device using two or more lenses to magnify things just not obvious?
user avatar
4 votes
3 answers
659 views

How do the phases of Venus prove heliocentrism?

I have been doing research about the Copernican Revolution, and one of the main arguments that caused many astronomers to change their minds was Galileo's observation of all phases of Venus. The proof ...
fartgeek's user avatar
  • 161
5 votes
1 answer
563 views

Which telescope(s) did Charles Messier use to catalog his 110 objects?

Charles Messier is known for (among other things) a catalog of "Messier objects". Neither article shows an image of "Messier's telescope", though the latter includes: Since these ...
uhoh's user avatar
  • 30.8k
2 votes
0 answers
84 views

Credible description of point sources and point spread functions in astronomy

I am looking for a credible source (or even the original sources) that describe point sources and/or point spread functions (PSFs) on astronomy. Unfortunately, the Wikipedia pages (point source, PSF) ...
mapf's user avatar
  • 121
25 votes
2 answers
7k views

Was Galileo expecting to see so many stars?

Beginner amateur here. I see mentioned many times that Galileo was surprised to see the moons of Jupiter and all that their existence proved, i.e. the Earth not necessarily being the center of ...
Theodore's user avatar
  • 359
23 votes
3 answers
5k views

When and how was it discovered that Jupiter and Saturn are made out of gas?

Was it due to appearance only or spectroscopic methods were used? Venus also has a thick cloud cover, how was it determined to be a rocky planet?
Astrodhan's user avatar
  • 341
2 votes
1 answer
205 views

What is this drawing about in "kitab al bulhan"?

Kitab al bulhan or "book of surprises" is medieval Persian manuscript written in Arabic. According to Wikipedia: The contents include subjects on astronomy, astrology and geomancy, ...
SamiM's user avatar
  • 29
2 votes
1 answer
704 views

About Year Zero

It is said that, in part due to a poor grasp of mathematics (the number zero to be precise) our forebears, when they developed the calendar went from 1 BC/BCE to 1 AD/CE. Year Zero is missing - it ...
Hudjefa's user avatar
  • 353
4 votes
2 answers
218 views

First time mention of coplanarity between Solar Systems planets

When comparing Galileo, Copernicus and Hypathia models to describe the solar system, each of them agree on coplanarity, based on their representations. Anyways, it was not until Kepler and Newton that ...
nuwe's user avatar
  • 771
15 votes
6 answers
4k views

What's the issue with Olbers' paradox?

I'm not quite grasping the reasoning behind Olbers' Paradox, or why an eternal, non-expanding and spatially infinite universe would be incompatible with a dark sky. For simplicity, let's suppose that ...
Alex Popescu's user avatar
4 votes
1 answer
315 views

What is the brightest nameless star?

Bright stars in the night sky traditionally have their own proper names, like "Sirus" or "Canopus". Most stars don't have names, but instead catalogue identifiers, like the Bayer ...
SE - stop firing the good guys's user avatar
4 votes
1 answer
302 views

Is pointing a telescope at a random place a viable astronomical strategy?

Recently I happened to be on the MAST portal, looking at jwst data. I happened to come across 2 interesting targets, “random place” and “another random place” This got me thinking. It’s almost ...
Topcode's user avatar
  • 166
6 votes
1 answer
136 views

First satellite of an asteroid (or double asteroid) ever imaged by delay-Doppler radar?

In comments about my previous bounty on the Space SE question Which deep-space spacecraft flew closest by Earth during a gravitational assist?, I started to look at the Galileo mission and ran across ...
uhoh's user avatar
  • 30.8k
5 votes
1 answer
71 views

Did de Sitter expect to disprove Ritz theory only with visual binaries?

Walter Ritz’s emission theory stated that some fraction of the velocity of an object was added to the speed of light emitted from it. Willem de Sitter pointed out a problem with this in the case of a ...
D R Ball's user avatar
9 votes
2 answers
1k views

How was the First Point of Aries measured in ancient times?

According to Wikipedia, usage of the Sun's position as the basis for a celestial coordinate system dates back at least to Babylonian times, and the current "First Point of Aries" system ...
Greg Miller's user avatar
  • 5,922
4 votes
2 answers
231 views

Which world did Carl Sagan know of with a million moons?

I recently read Carl Sagan's The Cosmic Connection. In it, he begins the seventh chapter with a series of claims to depict the universe as "vast and awesome." I'm particularly interested in ...
DreamlessOctober's user avatar
12 votes
1 answer
889 views

Early Milky Way depictions after Herschel?

We are all familiar with the 1785 drawing of the Galaxy by William Herschel, often quoted as the "First drawing of the Milky Way" Are there any other such historical drawings after this one?...
Gabriel's user avatar
  • 822
11 votes
3 answers
3k views

At what point in history was the idea of planets being spit out by the sun abandoned?

For context, at some point during the 20th century (and maybe earlier as well), the most popular planet formation theory and the one that was taught at (at least some) schools was the theory that the ...
Justin T's user avatar
  • 3,404
2 votes
0 answers
104 views

History, significance and "drama" (if any) of T-Tauri stars, especially the early bits?

In this answer to Can I write a systematic review as an undergraduate and get it published in a journal? in Academia SE I recounted my memory of an experience from circa 1980: I had an initially ...
uhoh's user avatar
  • 30.8k
1 vote
1 answer
249 views

What else can we learn from a Foucault pendulum? Have they ever been used to determine anything more than that the Earth rotates on its axis?

Background Each semester we have to make up projects for each course. This semester I took Cosmology and Astrophysics and we covered a vast amount of topics, from luminosity of stars to Einstein's ...
Parmeet Singh EP 066's user avatar
1 vote
1 answer
192 views

How much energy to shorten a synodic month by about 1.56%?

Suppose the moon underwent a single, massive, large-object bombardment event. About what number (or range) of about what mean mass of objects could shorten the synodic month by about 1.5633%? (Assume ...
Peter Heffner's user avatar
6 votes
1 answer
159 views

Doubt about a computation in Jules Verne

In his Aventures de trois Russes et de trois Anglais dans l'Afrique australe (The Adventures of Three Englishmen and Three Russians in South Africa), Jules Verne describes in some detail the geodetic ...
DaG's user avatar
  • 161
2 votes
0 answers
111 views

Empirical findings, Occam's razor, and the replacement of Ptolemaism by heliocentrism [closed]

C. S. Lewis's book The Discarded Image is about how to understand and how not to misunderstand medieval literature. In some parts he explicitly contrasts medieval with modern culture. In one of those ...
Michael Hardy's user avatar

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