Questions tagged [astrophysics]

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Schwarzschild's artificial planet

In a 1963 article by Robert Dicke ("The observational basis of general relativity"), there is a reference to a concept for a gravitational experimental device in the form of a big ball ...
Slereah's user avatar
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How did Kelvin square his low estimate of the age of the sun with the geological evidence?

Kelvin famously disputed geological estimates of the age of the earth because he said gravitational collapse couldn’t fuel the sun long enough. But even if gravitational collapse, not fusion, had been ...
GokuNarutoBosnia's user avatar
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Why wasn't the need for dark matter recognized until the 80's?

The need for dark matter was recognized in the 1980's, after Rubin and Ford presented their results on the rotation curves of galaxies. However, as early as the 30's, Fritz Zwicky inferred that there ...
usernumber's user avatar
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Earliest numeric value for helium D3 line

In late 1868, Norman Lockyer discovered the existence of the D3 emission line of helium in the solar spectrum. What was the earliest published example of a numeric value for the wavelength of this ...
WhatRoughBeast's user avatar
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How did Hertzsprung-Russell diagrams end up so confusing?

HR diagrams show in which of several sequences individual stars fall, each respecting the rough principle that hotter stars are of higher luminosity. (Sequences other than the main sequence may bend ...
J.G.'s user avatar
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What did the Italian Nobel laureate Riccardo Giacconi think about the Multiverse hypothesis?

Riccardo Giacconi (1931-2018) was an Italian astrophysicist who was awarded with the Nobel prize in physics back in 2002 for his important contributions to astrophysics. Since he was an astrophysicist,...
vengaq's user avatar
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Why is it that so many early astronomers and cosmologists wanted to believe in a static/infinite/eternal Universe?

I've been doing some research for a cosmology series and I'm struck by how many physicists and philosophers, from Newton to Einstein, had a notion that the Universe should be static and eternal. Why ...
Thomas's user avatar
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3 votes
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Earliest use of the word 'polytropic' to describe an equation of state or process

When and by whom was the word 'polytropic' first used to describe an equation of state or process of the form $P \propto V^n$? Why was this particular word chosen? The earliest use of the word that I ...
Kishore's user avatar
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When did the research field of Astrophysics begin?

I have this vague idea that Astrophysics morphed out of Astronomy as a field of study and research. I am curious if this is true and when did Astrophysics become separate from Astronomy as a field of ...
K7PEH's user avatar
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