How much physics do i need to know to embark on cosmology
Do i need to be a complete expert in GR???
It of course depends on what level of understanding you are aiming for, and what part of cosmology you'd like to study, but in general you don't need to be an expert in GR. A basic GR course (including a study of the FLRW metric) could be sufficient for many topics in cosmology.
thats quite a suprise
can you recommend me some text books on cosmology(leave aside weinbergs pop book)
I think I need to know which level you are at right now, and which level you are aiming for?
i know very little quantum field theory,some basic idea about GR,
miniscule amount of particle physics,...
Maybe Introduction to Cosmology by Barbara Ryden might be a good choice.
Assuming second or third year undergraduate physics and math as input, this well written book gives an elementary, but detailed and quantitative, treatment of the expansion of the universe, dark matter, dark energy, inflation, big bang nucleosynthesis, and structure formation (galaxies and superclusters of galaxies). Knowledge of general relativity is not a prerequisite. The FLRW metric is used and studied, but is not derived.
"Cosmology and Particle Astrophysics" (second edition) by Bergström & Goobar may be something. It is intended as an advanced undergraduate/graduate textbook, but is actually quite readable even for those with less knowledge, since it repeats the basic GR and QFT needed for the understanding of the rest of the book. The main focus is on dark matter and dark energy.
A comprehensive classic cosmology text is 'Cosmological Physics' by John Peacock. Depending on your maths and physics background, this may be a little advanced though. It's probably an upper undergrad/grad student level.
Another option (though possibly a little tricky to get hold of?) is 'First Principles of Cosmology' by Eric Linder. It's quite a short text by normal standard but presents things in an interesting way and provokes lots of good thinking from the reader.
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