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Prerequisites for cosmology 
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#1
Feb912, 12:15 AM

P: 339

What do I need to know before I can study Cosmology. I think I'm going to read this text:
http://www.amazon.com/CosmologyStev...8767963&sr=81 Cosmology by Steven Weinberg. I'm going to read this College Physics text first by Serway http://www.amazon.com/CollegePhysic...8767998&sr=11 And I will have a good grasp of calculus soon. What other math and physics do I need to know? Also what math does Cosmology employ most? 


#2
Feb912, 06:41 AM

P: 1,054

G & C itself requires a lot of background, or at least a lot of "mathematical maturity". For instance, look at the second equation in G&C  it shows the distance between two points in a nonEuclidean geometry, with *no* handholding. So if you haven't encountered that kind of geometry before you need to either (i) accept it and move quietly on or (ii) dig into Weinberg's references... and buy another book... which no doubt is equally high level... and requires another book... and another book... I remember haunting the university library and looking through dozens of books in desperate search of some "hand holding", and mathematical background for just about every page of Weinberg. It's that tough. Tougher than anything, except the book you're aiming to read... 


#3
Feb912, 07:46 AM

Mentor
P: 16,116

If you read the Amazon description of Weinberg's text, it says "it divides into two parts, each of which provides enough material for a onesemester graduate course."
If you read the preface of Serway's text (from the link you provided), it says "College Physics is written for a oneyear course in introductory physics usually taken by students majoring in biology, the health professions, and other disciplines including environment, earth and social sciences, and technical fields such as architecture. The mathematical techniques in this book...do not include calculus." So there's about 15 college courses separating those two books. 


#4
Feb912, 10:27 AM

Sci Advisor
P: 1,676

Prerequisites for cosmology
Weinberg's book is probably too advanced for beginning reading, being more appropriate to graduatelevel study.
You can begin to develop an understanding of the concepts and mathematics of cosmology without it, but eventually you're going to need to study general relativity. It is based on the mathematics differential geometry. 


#5
Feb912, 09:11 PM

P: 6,863

I like Dodelson's "Modern Cosmology". It something that a junior physics major can understand, and once you've finished Dodelson then Weinberg is going to make a lot more sense.
One other thing is that it would be helpful if you created a personal wiki page or a blog on the topic. There's a lot of "handholding" material on the internet that can get you from point A to point B, and someone needs to organize it, and it could be you. Something that I wish would exist is some sort of hypertext version of advanced physics texts, so that you start with Weinberg, and when you start with something that you are clueless about (which will start on page 2), you click on it, and it eventually it gets you to something that newbies can deal with. 


#6
Feb912, 09:17 PM

P: 6,863

Anyone hear of any sort of invention like that???? More seriously, the "click one piece of text to get to some other text" problem has been solved. The thing that no one has done (and Wikipedia has gotten closer than anyone else) is to actually work out the links themselves. The frustrating thing is that there is no technological barrier. The barriers are legal and administrative. We haven't got there yet, but we are really, really, really close. 


#7
Feb912, 09:18 PM

P: 6,863

Also modern cosmology involves a ton of statistics.



#8
Feb912, 11:05 PM

P: 534

Liddle's "An Introduction to Modern Cosmology" is quite readable (and short) as an introductory text. You might also want to complement it with a semipopular science book [more like a textbook actually] that I really like (some explanations are really good), try Duncan and Tyler "Your Cosmic Context"



#9
Feb912, 11:15 PM

Emeritus
Sci Advisor
PF Gold
P: 5,197

I like aspects of Dodelson as well, although it has its drawbacks. For a treatment that is even simpler still, I find that the chapters on cosmology from Galaxy Formation by Malcolm S. Longair to be pretty helpful. It's sort of at the level of "cosmology for observational astronomers." He spends one chapter giving a fairly perfunctory overview of GR, and then introduces the Friedmann equations in the next chapter. He states that they can be derived from the Einstein field equations for the case of an isotropic and homogeneous world model, but does not bother to do so himself. To the OP: for now, if you accept the Friedmann equations as a given, and if you are fairly wellversed in differential equations and calculus, then I think that this might be a good place to start, and you can get pretty far in understanding the properties of the world models and what they predict, as well as a good review of observational cosmology. 


#10
Feb1012, 01:20 AM

P: 6,863

It's not so much the authors, as the publishers. The reason that books are selfcontained is that it fits well with copyright law. If you have a "diffused textbook", it's not clear who gets paid what and how. I'm sure someone is going to work it out. If you want to get superhandwavy you can do cosmology is a Newtonian framework and then talk about how GR is different. This is useful pedagologically because a lot of the important features of cosmology are gravity model independent. That's what the professionals do. Someone works out the basic equations and then this gives a framework that people can use to do calculations is a more or less Newtonian setting. Now whether to what extent that's a valid way of doing things is a topic you can spend a few years writing your doctoral dissertation on (it's called the backreaction problem). The thing is that it's a hard problem and even smart people can deal with only one hard problem at a time, so one tactic is to massively simplify the GR model so that you can go deep looking at something else. Dark matter or galaxy evolution for example. One problem with going straight to Weinberg is that it's designed for graduate researchers who are going to be writing dissertations on the stuff. Once you get through Weinberg, then you'll be ready to start on your dissertation and start writing papers on cosmology. 


#11
Feb1012, 05:44 AM

P: 1,054

Cosmology by Michael Rowan Robinson Rowan Robinson has been a big name in observational cosmology in the UK since the seventies. I remember using the first edition in a second year undergraduate course many moons ago. I really enjoyed it  especially as I thought it was going to be a tough course, but it turned out to be easier than most courses I took. The biggest problem  it might make you complacent. The step from RR to Weinberg is a big one! The difference between beating your head against a pillow and beating it against a concrete wall :) The fourth edition is quite expensive. I picked up the third edition (1996) cheap and that should be good enough... it includes discussions of inflation and GUT. I've glanced at the following, "the new kid on the block (in the UK)", which also looks good at this level: An Introduction to Modern Cosmology, 2nd Edition by Andrew Liddle Both of these books recommend Weinberg (1972) for advanced study, so you are not going wrong with Weinberg, it's just it should be part of a five year plan! Liddle and RR can be used *now* to keep you interested... 


#12
Feb1012, 06:27 AM

P: 1,054




#13
Feb1012, 06:36 AM

P: 2

I recommend you to watch Susskind's GR and Cosmology lectures from youtube before going into any trouble reading all these books. Enjoy!!!!



#14
Feb1012, 06:52 AM

P: 1,054

Attribution & parallel development seems to be a big thing in the history of early 20th century cosmology! This can lead to excess attributions that just get silly  look up "Friedmann–Lemaître–Robertson–Walker metric" in Wikipedia: "Depending on geographical or historical preferences, a subset of the four scientists — Alexander Friedmann, Georges Lemaître, Howard Percy Robertson and Arthur Geoffrey Walker — may be named (e.g., Friedmann–Robertson–Walker (FRW) or Robertson–Walker (RW) or Friedmann–Lemaître (FL))". Rowan Robinson neatly cuts this to *one* option "Robertson–Walker metric", without mentioning the other permutations at all. In fact, if at all possible, he reduces the name to one. I guess that's why Lemaître gets mentioned but not Friedmann! I like RR's "historical figures extralite" approach just as much as his "math extralite" approach ! 


#15
Feb1012, 04:30 PM

P: 339

all around great advice. I guess I'll start with RR and just stick with the hand waving explanations for GR.



#16
Feb1012, 05:39 PM

Mentor
P: 16,116

I just took a look at RowanRobinson's book, and I looked at some of your other posts. I think you don't have the mathematical background yet for that, and you might need to work on your algebra first.



#17
Feb1212, 08:32 PM

P: 6,863

However, it's a useful approach from a teaching perspective. You start Newtonian. Then you bring in GR, and then you show how GR gives different results from Newtonian and why, and *then* you start talking about Riemannian manifolds and Ricci tensors. One reason that it works, is that if you just start with GR, you miss the "essential point" of cosmology which is that when you calculate the entire universe, the math in fact becomes much more simple because of symmetry. One analogy for what is going on is that you are trying to get to the top of Everest, and there are several ways of doing getting there. And in some of the places, it's easier now because someone has put a ladder to get over the difficult parts. 


#18
Feb1212, 08:33 PM

P: 71

prerequisites for cosmology: Passion



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