Questions tagged [history]

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

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75
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2answers
14k 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 ...
49
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4answers
14k views

How did Astronomers deduce that the Sun was not a ball of fire?

Its common knowledge that people used to think that the sun is a ball of fire or molten metal, but when did science start to prove otherwise?
35
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3answers
707 views

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 ...
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2answers
4k views

How was the mass of Venus determined?

The mass of Venus seems rather complicated to determine to me: Venus doesn't have any satellites, so you can't just apply Kepler's third law (like you would with Jupiter or Saturn for instance) to ...
29
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2answers
3k views

We know what a nova is, but how?

I work with astrophysicists and require some basic knowledge of many astronomical sources, however research priorities often demand that most of human knowledge on a subject be taken for granted. I ...
28
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2answers
7k views

How did Eratosthenes know that the sun is far away?

The famous measurements and calculations done by Eratosthenes around 300 BC are very widely known. He concluded correctly that the circumference of the Earth is about $252\,000$ times the length of an ...
28
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1answer
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 ...
25
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9answers
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Simple experimental evidence that Earth revolves around Sun

What are the simplest experiments or calculations that give evidence that the earth revolves around the sun? Can you please explain them and reference the history? Many simple explanations such as ...
25
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1answer
5k views

What's the reason that we have a different number of days each month?

It always was interesting for me to understand the answer for the question: What's the reason that we have a different number of days each month? If the month is fixed on the time that the moon ...
23
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2answers
7k views

How did Kepler “guess” his third law from data?

It is amazing that Kepler determined his three laws by looking at data, without a calculator and using only pen and paper. It is conceivable how he proved his laws described the data after he had ...
23
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3answers
3k views

When did people first measure that the Earth was closest to the Sun during January?

When we talk about the reason for the seasons, we usually have to dispel the misconception that seasons are caused by being close and far away in the Earth's elliptical orbit. And usually, we ...
22
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2answers
4k views

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 ...
21
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3answers
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When was it worked out/discovered that our sun can't go supernova?

As the title says, when did we realise with reasonable confidence that our star is not going to be going out in a supernova blaze of glory? I ask because a while ago I read The Songs of Distant Earth ...
20
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4answers
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Metallicity of Celestial Objects: Why “Metal = Non-metal”?

Metallicity of objects refers to the amount of chemical elements present in it other than Hydrogen and Helium. Note: The other elements may or may not be actual ...
20
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2answers
2k views

When was the martian dichotomy first observed?

The North and South hemispheres of Mars are very different one from another. They have different elevations, different crust thickness, different surface ages. This is known as the martian dichotomy. ...
20
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1answer
578 views

What are Kepler's laws (as he wrote them)?

There are of course many, many sources that quote Kepler's laws of planetary motion. This is preventing me from finding out what I really want to know: which is - what are Kepler's laws as he wrote ...
15
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8answers
4k views

Has great eyesight been necessary for astronomers?

In a different (but somewhat related) field, some baseball stars have been known to have "baseball eyes." That is, an exceptional ability to visually follow the trajectory of a 90+ mph baseball to a ...
15
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2answers
3k views

Has radio astronomy ever been done on objects that appear very close to the Moon? Is this avoided?

This answer to Which kinds of astronomical observations most need to avoid the Moon being up? mentions For completeness - radio, mid-infrared and mm-wave observations are unaffected (unless the ...
15
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1answer
1k views

When did scientists discover that the Sun has a life cycle and that it is going to die?

I have been researching the history of scientific studies about the the Sun. However I have been unable to find out much information about how the scientific consensus started forming around stars' ...
13
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1answer
24k views

How was the Earth-Sun distance originally calculated?

AFAIK it was possible long before the first interplanetary probes. Who did it?
13
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2answers
319 views

What was the first astronomical measurement which demonstrated that “the Earth is surrounded by vacuum”?

The question Who was the first to realize that the Earth is surrounded by vacuum? was closed because some users felt it was answered by answers to a different question in an different SE site: Who was ...
12
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3answers
1k views

Has anyone ever tried to make a simple telescope using ice?

I grew up with long cold winters, and saw a lot of remarkably transparent ice formed by refreezing meltwater, both in puddles and ponds, and in large icicles. I'd always thought about making optical ...
12
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1answer
2k views

Was the progress of astronomy in the 1800s surprisingly slow, and if so why? [closed]

The 1800's was a century of fantastic scientific discoveries in chemistry, geology, biology, engineering and so on. Is it correct to say that astronomy did not keep up with this development? And if ...
11
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3answers
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How did our ancestors discover the Solar System?

I wonder, how did our ancestors discover the Solar System? They did not have any telescopes to see distant objects, right? Even a planet looks like a star from a distance. They discovered the ...
11
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1answer
672 views

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 ...
10
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4answers
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How much does the sky change in a few thousand years?

The "fixed stars" are not actually fixed, the earth's tilt changes over time etc., but all that happens slowly on human timescales. Imagine a Babylonian astronomer (or astrologist?) ...
10
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2answers
406 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'...
10
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2answers
226 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, ...
10
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5answers
2k views

Where to obtain Tycho Brahe's data?

I would like to obtain Tycho Brahe's data on Mars. What would be an authoritative source? One source I could find is this page (the data is given as an Excel file) but I have no idea can that be ...
9
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1answer
814 views

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 ...
8
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2answers
755 views

Which telescope's model is being shown to Albert Einstein in this file footage? What event might this be?

In the Economist video Why does time pass? there is some file footage of Albert Einstein attending some event where a model of a large telescope is on display, and being described to Prof. Einstein. ...
8
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5answers
370 views

Do astronomers have an established, systematic way for saying what does or doesn't orbit what? (e.g. “Mars orbits Earth”)

A recent comment An object far enough away can certainly orbit the Moon and the Earth (and the Sun) -- Mars, for instance does this. An object in the Earth-Moon L2 is also orbiting both the Earth ...
8
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2answers
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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. ...
8
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2answers
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How did Kepler determine the orbital period of Mars?

As I understand it, Kepler used the orbital period of Mars, along with observational data of Mars' and the sun's position in the sky to derive the orbits of Earth and Mars. (As described, here: https:...
8
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3answers
427 views

When did people discover that the Earth is not an ideal sphere, but a little flattened?

When did people discover that the Earth is not an ideal sphere, but a little flattened? And if you know, who was the first person to discover it?
8
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1answer
181 views

When was it realised that most major moons orbit in the equatorial plane of their parent planets?

Inspired by the discussion of the moons of Uranus providing a clue to the planet's axis of rotation in this question, I'm wondering when it was realised that the major satellites are typically located ...
8
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1answer
364 views

How did astronomers first come to understand that the Sun's core was a gas?

I was reading a very old book (around 1850) on astronomy and the author explains Sun spots as a phenomena where you can see the black planetary like hard core of the Sun through two different ...
8
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1answer
220 views

Why was Pluto's resonance not discovered until 1965?

Over here, I was shocked to learn: The Neptune–Pluto system lies in a 3:2 orbital resonance. C.J. Cohen and E.C. Hubbard at the Naval Surface Warfare Center Dahlgren Division discovered this in ...
8
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5answers
2k views

Naming of the planets of the solar system

Planets of the solar system have been named with Roman mythology gods names. I have a few questions on my mind concerning that subject for a while: Who decided to name them like this? When did the ...
8
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1answer
93 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 ...
8
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1answer
289 views

When did the first annular eclipse happen?

A few hundreds of millions of years ago, the moon was closer to the Earth than it is today and hence was of a bigger apparent size. This made every solar eclipse either total or partial. Over the ...
7
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1answer
664 views

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 ...
7
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2answers
223 views

Are there stars in the first photo from space?

Wikipedia has this photo (see below) labelled "First photo from space" which was taken in 1946 from a U.S. launched German V-2 rocket. Approximately two thirds of the image is a section of the Earth ...
7
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2answers
521 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 ...
7
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1answer
273 views

Why didn't Johannes Kepler use data about more planets?

In Astronomia Nova (1609) Johannes Kepler used observations of Mars in order to refute circular orbits. Throughout Astronomia Nova he hardly even mentions other planets than Mars, Earth and the Sun (...
7
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1answer
303 views

First observation that the Sun and Jupiter (and friends) move around a common barycenter?

Answers to the question How did Kepler determine the orbital period of Mars? describing careful observations centuries ago got me thinking. What was the first analysis of observations that directly ...
7
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0answers
177 views

Explanation of an imaginary transformation occurring in the determination of trigonometric series for the elliptical equation of the center

One of the oldest problems in astronomy, which dates back to to the time of Kepler, is the problem of development in infinite trigonometric series of the "equation of the center" - to ...
6
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2answers
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.
6
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3answers
4k 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 ...
6
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1answer
202 views

What exactly is interplanetary scintillation; what was the Interplanetary Scintillation Array looking for? Did it successfully observe any?

The Interplanetary Scintillation Array is the radioastronomy observatory (i.e. big antenna) where the first pulsar was discovered by then graduate student Jocelyn Bell Burnell through careful and ...