Questions tagged [history]

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

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6 votes
3 answers
5k views

How did the authors of Surya Siddhanta find the diameters of other planets in the solar system?

The Surya Siddhanta, "a Sanskrit treatise in Indian astronomy from the late 4th-century or early 5th-century CE" is truly a great work. But how was it possible for the writers to find the exact ...
3 votes
1 answer
121 views

Mercury mapping attempts before Mariner 10?

Mercury's surface was not mapped up-close until Mariner 10 passed by in 1974. This was followed by MESSENGER in 2008. I have seen several attempts of mapping Mars that came before space exploration, ...
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0 votes
1 answer
2k views

How was the time of equinox measured in ancient times?

In the book "The Crime of Claudius Ptolemy" by Robert Newton, on page 81, it reads as follows: When we measure the time of a solstice, we measure the time when the meridian elevation angle of the ...
28 votes
1 answer
4k views

How did Ole Christensen Romer measure the speed of light?

How did Ole Christensen Rømer, who in 1676, shortly after Galileo's death, was said to have measured the speed of light as 220,000 km/s by timing the orbits of Io around Jupiter? My only guess is ...
77 votes
2 answers
16k views

Could the dinosaurs have seen the asteroid that killed them?

Wikipedia says the Chicxulub impactor is thought to have been a 10-15 km diameter object. Would it have been visible to a (human*) naked eye before impact? And if so, would it have appeared like a ...
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1 vote
1 answer
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Is the American Astronomical Society 230 years old?

The BBC News item Light shed on mystery space radio pulses is interesting enough in its own right. But I noticed that it is reporting on news from the 231st meeting of the American Astronomical ...
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2 votes
0 answers
220 views

How does Ptolemy prove in the following excerpt that the Earth could not be outside of the axis spanning between the poles of the celestial sphere

I have trouble interpreting the following excerpt: “Against the first of these three positions militate the following arguments. If we imagined [the earth] removed towards the zenith or the nadir ...
3 votes
1 answer
321 views

How did Ptolemy prove in the following excerpt that the Earth is not cylindrical?

I have trouble interpreting the following excerpt: “Nor could it [the Earth] be cylindrical, with the curved surface in the east-west direction, and the flat sides towards the poles of the ...
4 votes
0 answers
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What is a "limited array"?

I'm reading about the history and making of ESO's Very Large Telescope and I've found this article that says the scientific community had a choice between three suggestions: a one-piece 16m-telescope, ...
5 votes
1 answer
2k views

When did astronomy first discover that the stars are bigger than the moon?

We take it for granted these days that the stars are unimaginably bigger than the planets and the moons. But when you look at the sky, it does not appear this way. The moon looks bigger and brighter ...
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4 votes
1 answer
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What kind of reddish wood is it exactly that was historically used to line the inside of observatory cupolas (domes), in order to absorb moisture?

I was told that it was "cedar", but that is an unclear term botanically.
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1 vote
2 answers
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What is the oldest known prediction of constellation positions?

Would someone know of a good reference on the oldest known predictions of constellation positions? How far ahead could accurate positions be predicted? For example, could current constellation ...
3 votes
0 answers
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Why weren't Lunar meteorites identified until 1982?

According to Wikipedia the first meteorite of Lunar origin wasn't identified until 1982. Today 306 Lunar meteorites have been identified. Why weren't they identified as Lunar already a decade earlier,...
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37 votes
3 answers
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If you lived on the far side of the Moon, how could you infer the existence of Earth?

Suppose that you deposit an astronomer, armed with our current knowledge of orbital mechanics, on a dome on the far side of the Moon, so that the Earth is perpetually hidden from them. (And, of ...
0 votes
1 answer
231 views

Why would there be no day/night cycle even though the firmament would still be rotating, according to Copernicus

In chapter 6 of "The Revolutions of the Heavenly Spheres" where Copernicus maintains that the heavens are immense compared to the size of the Earth, the Edward Rosen translation of the book states ...
10 votes
2 answers
238 views

How did we first determine the Earth's departure from sphericity?

I'm quite interested to know the history of the study of the Earth's departure from spherical symmetry. What were the first methods used to model the non-spherical geometry of the Earth? For example, ...
11 votes
1 answer
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What was the "brilliant new star in Aquila" on June 8, 1918, just after the solar eclipse?

This great answer about the US Naval Observatory's $3,500 expedition to Baker City Oregon to observe the June 8, 1918 total solar eclipse links to the January 1919 Popular Astronomy article about the ...
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23 votes
2 answers
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What exactly is the "paradox" in Olber's Paradox?

To the extent of my understanding, Olber’s paradox states that if the universe was static and homogeneous, we should see a star at every point in the night sky and therefore the night sky should be ...
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1 vote
2 answers
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What is Copernicus referring to when he states that "circles have poles different [from the earth's]"

In chapter 4 of "The Revolutions of the Heavenly Spheres" where Copernicus maintains that the objects in our solar system have circular orbits or orbits compounded of several circles, the Edward Rosen ...
2 votes
0 answers
95 views

Was the Crab Nebula to the southeast of Zeta Tauri 1,000 years ago?

I've been reading about SN 1054 and how most professional investigators believe that it is the Crab Nebula today. But the wiki article has this to say: The location of the guest star as "to the ...
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5 votes
2 answers
903 views

How was the first exoplanet detected?

How was the first exoplanet discovered? What method was used to detect it?
4 votes
4 answers
1k views

How did the Ancients understand the ecliptic using the Ptolemaic system

I studied the Farnese Atlas and I wonder how did the Ancients discover the ecliptic, the equator, etc. with the Ptolemaic system namely without knowing that the Earth rotates on itself, especially for ...
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1 vote
1 answer
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How are the elevations of the poles proportionate to distances of earth that have been traversed according to Copernicus

In chapter 2 of "The Revolutions of the Heavenly Spheres" where Copernicus maintains that the Earth is spherical, the Edward Rosen translation of the book states that the elevations of the poles ...
1 vote
2 answers
331 views

Celestial navigation from scratch

Is it possible to establish one's longitude and latitude by observing the stars? Can you use observations of the stars to find the relative distance between two locations, which would be useful in map-...
0 votes
2 answers
206 views

When were the horizontal and equatorial celestial coordinate systems invented?

When were the Alt-az system and the RA-dec system first used?
1 vote
3 answers
323 views

Why the continued obsession in measuring the year as a multiple of days?

Pick a any notion of year and any type of day measurement. Outside of history and the common cycle of day an night, why are these viewed as integrally or even fractionally commensurate? Why all the ...
8 votes
2 answers
589 views

Was there ever a hypothesis about a planet called Biga?

I just re-read a popular astronomy book that was published when I was a child, about 1973. It starts with an interview to Harold C. Urey where the interviewer asks about a hypothetical planet in our ...
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Kepler - Creating the Ellipse (Astronomia Nova)

In Chapter 58 in Astronomia Nova, Kepler made his final step to finally create the ellipse (for the orbit of planets) http://science.larouchepac.com/kepler/newastronomy/part4/58/index.html In the ...
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3 votes
2 answers
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Exoplanet hunters ignored or ridiculed in the 1980s or 1990s?

I recently came across this youtube video, in which a few people are singing about the history of exoplanet discovery. It suggests that, in the 1990s, exoplanet hunters were largely ignored or ...
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9 votes
1 answer
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Which star did Uranus occult in 1977 when the planet's rings were discovered?

In 1977, Uranus occulted a star, and the starlight flickered 40 minutes before and after the actual occultation, revealing Uranus' rings.This is common knowledge to astronomers, but what I can't find ...
1 vote
1 answer
494 views

Did Earth "tilt" seasonally before it was accepted that the world was not flat?

Before it was widely accepted that the Earth was round, how did astronomers describe the yearly movement of the sun to south in the Northern Winter that produced the seasons? Did the Earth wobble or ...
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6 votes
1 answer
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Why is the symbol of Vernal Equinox ♈?

Since the direction of Vernal Equinox lies in the Pisces constellation, why is its symbol Aries? Shouldn't it be ♓ ? Is this a historical anachronism, only invalidated by axial precession of Earth?
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7 votes
1 answer
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Calculating orbits using observational data

How did astronomers in the 18th and 19th centuries used to calculate a comet's or planet's orbit using observational data, given that this data is relative to a non static reference point (i.e. the ...
3 votes
1 answer
445 views

Numbers 80 to 85 in Ancient Astronomy

Do any numbers in between 80 and 85 (or thereabouts) hold any relatively important or relatively obvious meaning in ancient astronomy ? A few clarifications: By ancient I mean related to human ...
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4 votes
2 answers
748 views

How many judges sat on Galileo's trial over heliocentrism and who were they exactly?

I saw several chronologies of the trial online but most of them only mention the name of Urban 8 as involved in the actual court proceedings. How many judges were involved and who were they exactly? ...
1 vote
0 answers
40 views

How many judges sat on Galileo's trial and who were they exactly? [duplicate]

I saw several chronologies of the trial online but most of them only mention the name of Urban 8 as involved in the actual court proceedings. How many judges were involved and who were they exactly? ...
3 votes
2 answers
277 views

Was the radiant of the Perseid meteor shower ever near Vega thousands of years ago?

The ancient Chinese story of the Weaver Girl (Altair) and the Cowherd (Vega) tell of starcrossed lovers who are only allowed to meet once a year on the 7th day of the 7th (Chinese) lunar month, ...
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5 votes
1 answer
188 views

Why was the size of the solar system not defined by Mercury Transits?

The first measurements of the (absolute) size of the solar system was made using the Transit of Venus, an event that arguably will only happen twice in a lifetime. Transits of Mercury occur far more ...
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0 votes
1 answer
138 views

When was the nearest star discovered? [closed]

When historically did we realize that the Sun is a star, like all the others? An answer was posted, then the question was put on hold. I would like to answer: If indeed someone asserted that the Sun ...
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2 votes
3 answers
4k views

What is the first recorded reference to the Moon being a satellite of the Earth?

I saw a list recently of the moons of the various planets and the discoverer(s) and date of discovery. Earth's Moon was listed as Unknown. I know you don't 'discover' a huge disc in the sky. But ...
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1 vote
2 answers
82 views

How was precision astrometry done before digital imaging?

Did they just put a ruler on the photographic plate? Quite some precision must have been required to discover Neptune from its influence on Uranus for example.
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1 vote
1 answer
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Could the Sun's bending of light be measured on photographic plates before Einstein's prediction?

It was predicted from Newtonian physics already in the 18th century that gravity should bend light, but not by as much as general relativity predicts. This was first confirmed during a solar eclipse ...
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6 votes
1 answer
177 views

Discovery in Astronomy vs one in Physics - do they differ in required burden of evidence?

Discovery in Astronomy/Astrophysics (of astronomical objects) vs discovery of physical phenomena in experimental Physics (as such) - do they differ in required burden of evidence (with the notion, ...
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5 votes
4 answers
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What planet is better than earth to infer solar system configuration?

The mankind had to work some centuries to infer the real configuration of solar system, starting from greeks, Ptolemeus, until Copernicus, Galilei, Kepler, Newton etc. Is there any planet where we ...
2 votes
2 answers
256 views

When did the Scutum constellation receive its current name?

While cleaning my desk, I found an out of date star map (puts the cleaning into perspective, huh?) where the Scutum constellation is still referred to as Scutum Sobiescianum). This is the original ...
3 votes
1 answer
451 views

Do all planets rotate in the same direction in relation to each other?

In other words, does everything spin counterclockwise according to their axes (in relation to each other)? I suppose my question goes for stars, moons and other objects too. But then again, all you ...
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6 votes
1 answer
399 views

How were the orbits of planets first mapped out?

I'd like to know how the orbits of planets were first 'mapped out' and to understand the maths behind it. e.g. How do we know what position in space a planet will be at certain time so that spacecraft ...
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6 votes
2 answers
1k views

When was the term "orbit" (in the modern sense) first used and by whom?

Wikipedia coyly suggests that some notions and views kept circulating (apparently since Adam and Eve) until finally Kepler, of all people, ... etc. I find this hard to believe. Please elucidate.
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10 votes
2 answers
446 views

Acquirable Raw Data in Amateur Astrophotography

What raw data can I possibly acquire from an 8" Classical Dobsonian Telescope, and a DSLR? Could anything eye-opening to amateur astronomers be computed or calculated first-hand with such equipment? I'...
9 votes
2 answers
6k views

Why does the Hertzsprung–Russell diagram's x-axis go from large temperatures to lower?

In my textbook, the H–R diagram’s y-axis is $\log(L/L_{\odot})$ and values are higher as we go higher on the scale, but the x-axis is $\log(T_\text{eff})$ and gets smaller as we proceed to the right. ...
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