B What’s more “important": GR or QM?

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Let’s say to the average Astronomer conducting research; generalizing the research to “astronomy” ; which would be more useful for the “average” Astronomer on a day to day basis: Quantum Mechanics or General Relativity? Obviously most are, but which so more? Which would be referred to more?
 

BvU

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Depends on what she is interested in. Without context a rather meaningless question. What good soes it to have an answer ?
 

fresh_42

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Let’s say to the average Astronomer conducting research; generalizing the research to “astronomy” ; which would be more useful for the “average” Astronomer on a day to day basis: Quantum Mechanics or General Relativity? Obviously most are, but which so more? Which would be referred to more?
GR is where astronomy takes place, so I think it can be regarded as a basic skill for astronomers. On the other hand I just watched a documentary yesterday about the possibility that Cassiopeia A has left a quark star instead of a neutron star. Seems, as if a sound foundation in physics in general will be necessary for an astronomer.
 

Vanadium 50

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What's more important, addition or subtraction?
 

sophiecentaur

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The effects of relativity are much harder for Astronomers to detect than the resulting line absorption spectra . that can easily be observed with simple equipment. (Diffraction grating or DVD surface). So you could say that QM, in one way, is more Obvious, rather than more Important.
GR was only observed under solar eclipse conditions - and comparatively recently, too.
 

Ken G

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Ironically, the basic fact is that neither GR nor QM are usually needed on a daily basis for most astronomers. Only a cosmologist or black-hole astrophysicist will need GR daily, and only a spectroscopist or white dwarf modeler will need QM daily. However, these are the two main theories for explaining what is happening everywhere, so they will underpin everything else. So I think it depends on how deeply the astronomer wants to feel their results are anchored into the foundations of physics as to whether or not they regard GR or QM as important at all, not to mention which one is more important. With that in mind, QM is more fundamental, because it is involved in every single astronomy observation, it is just a matter of whether or not the astronomer cares about that fundamental connection in practice. In that same vein, it would be virtually impossible to obtain a PhD in astronomy without several courses in QM, but you can do it with quite little GR if you navigate your course that way.
 

Zeke137

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which would be more useful for the “average” Astronomer on a day to day basis: Quantum Mechanics or General Relativity?
Your question is too limiting - you're neglecting Special Relativity (SR), which is far more relevant than GR on the scales of stars and smaller - excepting black holes and neutron stars. SR figures also strongly in QM when particles or systems are travelling at appreciably relativistic speeds.

The study of QM is essential if one wishes to understand how electrons, atoms and molecules work and either emit, or interact with, EM radiation. So, astronomers need to know QM to some degree. As @Ken G says, study of GR could be avoided if one structures ones' course matter in that way. A budding astrophysicist, on the other hand, must study all three, QM, SR and GR, and a whole lot else, in depth in order to become a fully-fledged astrophysicist.
 
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