Questions tagged [astronomy]

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

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13
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3answers
5k views

When did humans realize that there is no air on the Moon?

What is the easiest evidence that there is no air on the Moon? Frankly speaking, I myself have no idea how to prove it.
7
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1answer
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Hevelius-Hooke dispute

Johannes Hevelius of Danzig (1611-1687) was the most famous astronomer of his time, and also the last famous astronomer who did not use telescope. Most books on the history of astronomy (and even the ...
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Who found out about galaxies? [closed]

As the world developed new technology, astronomers discovered more celestial bodies, such as asteroids and black holes and such. Galaxies were probably discovered long ago before these modern ...
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3answers
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Why didn't Aristarchus' theory of Heliocentrism stick?

This might be more a question for historians, but it's a question I've given some thought to. By using what was essentially Euclidean geometry, Aristarchus was able to calculate, with some measure ...
6
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3answers
310 views

Who was the first person to use physics to suggest that both the Sun and the Earth move?

I imagine it to be Isaac Newton, who brought the discussion of "force" rather than "center" into the modeling of orbits. I imagine that prior to Newton's forces, one had to be either a geocentrist or ...
18
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3answers
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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 ...
5
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2answers
156 views

Did Schiaparelli comment on the martian canals debate?

It s well known that in 1888, Italian Giovanni Schiaparelli announced finding a network of narrow lines on Mars, which he described as "canali," which a lot of English speakers including American ...
3
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0answers
810 views

Was Kepler aware of the following golden relationship between the planets?

Was Kepler aware that Venus and Mars have a golden section relationship other than that he attributed to them in his 5 perfect solids model of the Solar System? The dodecahedron and the icosahedron, ...
5
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3answers
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How long did it take to prove that the Earth revolves around the Sun?

I get that Galileo Galilei was a major contributor in proving the helio-centric theory, and same goes to Sir Isaac Newton. The battle for the theory to become law took centuries to prove. People ...
11
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3answers
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Who first distinguished planets from the stars?

This is a pretty straightforward question, when the first observations of the night sky were being made, who was the first person to suggest that a planet, say Mars, was not a star, in the sense that ...
18
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3answers
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Who first measured the distance to the Moon? How was it done?

Who first measured the distance to the Moon? How was it done? I think it had to happen after Newton, but I am not sure.
14
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1answer
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How did Babylonians figure out that the evening star is the morning star?

Hesperus (Roman Vesper) is the name ancient Greeks gave to the evening star that appears in the sky for an hour after the Sun sets. Phosphorus (Roman Lucifer, sic!), was the name of the morning star ...
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3answers
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Why should February have 28 days?

According to the Gregorian calendar the second month i.e. February have 28 days and in a leap year 29 days. I am not sure what calculations(science) it takes to decide the total number of days in ...
7
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1answer
127 views

When did the idea of naming asteroids after humans come about?

There are some trends to naming celestial objects: Planets and moons in the solar system may be named after ancient Greek and Roman gods Comets may be named after their discoverer Asteroids may be ...
17
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1answer
370 views

Did Archimedes use epicycles in his planetarium?

Archimedes constructed a planetarium where as described by Cicero "he had thought out a way to represent accurately by a single device for turning the globe those various and divergent movements with ...
6
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1answer
266 views

When was the airless void above the earth discovered?

For a very long time, people had no reason to believe that an airless void could exist in nature at all, whether above the earth or anywhere else. According to Descartes, in his 1633 work The World, ...
6
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1answer
678 views

Who discovered the “Comet” as a celestial object?

Who first discovered that comets were physical objects with a Keplerian orbit? Was this accidentally discovered or was it discovered as part of an intentional effort by astronomers after they ...
23
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5answers
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Is there an astronomical reason behind the order for the names of days of the week?

The seven days of the week seems to be commonly named after celestial bodies. What I find curious is that all seven days apparently share the same names in both West and East. Sunday is, of course, ...
19
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2answers
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When did it become possible to predict the time and place of solar eclipses?

That is, when did astronomy figure out how to predict when and where a solar eclipse will be visible? It seems people noticed fairly early on that the Sun, Moon and Earth return to the same ...
19
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1answer
561 views

Before 1964, did scientists generally believe there was life on Mars?

Mariner 4 was the first spacecraft to return photographs of Mars from near the planet, making its flyby of Mars in 1964. Those photographs showed what appeared to be a barren, desert surface. ...
11
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1answer
259 views

Division of the circle and compass constructions

It is well known that every construction that can be performed by a compass and a ruler can be also performed by a compass only. This is a good (and difficult) exercise in elementary geometry. My ...
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2answers
374 views

What happened in astronomy between Hipparchus and Ptolemy?

Hipparchus applied Apollonius's epicycle/eccenter construction to the motion of the Sun and the Moon, but not to the planets. There are speculations about epicyclic gears for planets in the ...
19
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1answer
367 views

When & how was it known that our Sun is the same thing as the night time stars?

Who was the first person to conjecture that our Sun is just another star? Relatedly, what was the first evidence that this was true?
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What data did Kepler work out his laws from?

It's well known that Kepler worked out his laws by fitting curves to Tycho Brahe's data on the trajectories of planets through the sky. What was this data? How does one record the trajectory of a ...