Cosmology Definition and 951 Threads

Here is the Penn State press release http://www.eurekalert.org/pub_releases/2007-07/ps-whb062907.php called "What happened before the big bang" the press release evidently covers much of what you need a subscription to read in Nature Physics magazine, or else have to get it at your university...

By quantum cosmology QC I mean research using a quantized version of the familiar classical Friedman-LeMaitre model used in mainstream cosmology. Quantum cosmology is beginning to have an impact on regular cosmology. It offers answers to certain puzzles and also prospects of testing QC...

If you want an accessible overview of quantum cosmology try this TOC: https://www.physicsforums.com/blogs/hellfire-3727/category/interesting.html Hellfire covers different attempts made since the 1960s, and by comparing them (and showing historical development) makes the whole subject...

From the Review of Mainstream Cosmology thread. Here I have started just such a thread. This thread is not the place to discuss a multitude of speculative ideas, rather it is intended as a discussion of observations that may raise questions about the consensus \LambdaCDM model. I start...

Edit: Thread started at the same time as Garth's on the same topic, go https://www.physicsforums.com/showthread.php?t=170753" instead!

Hello, I am 17 and from England. I have never really been good at maths, I find equations and such difficult to comprehend - this was the reason I decided not to take physics in college but rather art subjects, and luckaly enough for me I have always had an apparent gift when it comes to...

Hi marcus! It seems to me that there are many different approaches, from around the world, that are converging at an accelerated pace. Maybe not? … It might just be my desire to understand minimum length. http://arxiv.org/PS_cache/arxiv/pdf/0704/0704.2397v1.pdf The Quantum Configuration...

CONGRATULATIONS TO Martin Bojowald! http://arxiv.org/PS_cache/arxiv/pdf/0704/0704.1137v1.pdf Lattice refining loop quantum cosmology, anisotropic models and stability Martin Bojowald∗ 09 April 2007 Standard Theory SU(3)xSU(2)xU(1).…. String …. Have not done it. He is the first to...

There's no debate which post-SM approach the vast majority of HEP/particle physicists prefer: string theory. While I don't know what the vast majority of post-SM, post-GR approach cosmologists, astrophysicists, astronomers prefer, loop quantum cosmology or string cosmology, in solving a...

i have 2 questions: 1. what is the difference between astronomy, astrophysics and cosmology? 2. what did Alan Guth mean when he said, "The universe is the ultimate free lunch"?

mm k. So. As lots of other students are at the moment, I am currently preparing for a presentation. My chosen topic: alternatives to the FRLW model. What I'd appreciate from you guys is simple; I've been coming here long enough to notice that everyone has their own little deviations and...

Homework Statement Reading about the raditation dominated era I saw that the radiation energy density today was given by: \rho_r = \frac{\pi^2}{30} g_* T^4 = 8.09 * 10^{-34} g/cm^3 where g_*=3.36 is the degree of freedom of the radiation (equivalent) and T=2.75 K is the CBR...

People might be interested in a new paper, namely Cosmic clocks, cosmic variance and cosmic averages David L. Wiltshire 72 pages, 5 figures http://www.arxiv.org/abs/gr-qc/0702082 which demolishes DE (yet again!).

I am an public health/environmental student... I'm never taken any philosophy or anstronomy courses in my life. I am taking a course this semester that I thought was going to be more about the environment and turned out to be very abstract and philisophical. My first assignment is due this week...

Hi, I'm new to this forum, but saw that everyone was so kind and helpful, so was wondering if anyone could help me with a couple of things.. How does one calculate the age of the universe using Hubble's constant, if the constant is in km/s/Mpc? Do we know the critical density of the...

her new url is http://faculty.cns.uni.edu/~morgan/ajjar/Cosmology/cosmos.html her cosmology calculator is a handy resource especially since Ned Wright modified his cosmology calculator earlier this year----July sometime. Now, with Wright's, you can't input a redshift z. You have to input a...

I was intrigued by this paper and the approach: http://arxiv.org/abs/gr-qc/0611090 Cosmology as a search for overall equilibrium Authors: Carlos Barcelo Comments: 9 pages, 1 figure "In this letter we will revise the steps followed by A. Einstein when he first wrote on cosmology from the...

I've just been reading some of these threads, as i am quite interested in cosmology. I was wondering about a possible cosmology of the universe that i haven't really seem written about anywhere. What if, each point of the universe is both the centre AND edge of the universe? If the...

http://arxiv.org/abs/hep-th/0610211 Authors: Raphael Bousso Comments: 38 pages, 6 figures. Based on a talk given at the conference in honor of the 90th birthday of Charles Townes (Berkeley, October 2005), and on a colloquium at Stanford University After reviewing the cosmological constant...

How would our cosmology change once we have the ability to significantly escape our planet, our solar system, or our galaxy? Must we evolve socially or genetically to realize extended space travel? Might we first attain the ability to transform virtually through the cosmos? Would the...

Hello, I am a non-science student with a huge interest in cosmology and modern physics. I've read Micheal Greene's "Elegant Universe" and "Fabric of the Cosmos" a couple of times, and I loved them. What else do you recommend? (I know about Stephen Hawking's 2 books, and I hope to read them...

Just a quick note to say that Riofrio now has evidence of a changing speed of light. See her blog: http://riofriospacetime.blogspot.com/ :smile:

Hello all, This is my first post here and so I hope I am posting in the appropriate section. My question is actually related to both Physics and Discrete Mathematics. I'm writing a very general essay (no rigorous derivations or extremely involved mathematics) about Markov chains as they are...

This may not be a new idea, I haven't read it anywhere else. Imagine the big bang scenario. Imagine an expanding sphere, like a bubble. Imagine that the "skin" of the sphere is thick, say thirty billion lightyears and as the sphere expands, the "skin" gets thinner. Imagine a coordinate system...

INCOMPETENTS! There I said it. I was distracted just now at the library by this week's Newsweek cover, subheadline "Our changing view of the universe..." Of course our understanding of the cosmos has been jolted in recent times, and it's obvious what I'm talking about - a professional society...

http://arxiv.org/abs/astro-ph/0608644 Wolfgang Priester: from the big bounce to the Lambda-dominated universe James Overduin, Hans-Joachim Blome, Josef Hoell 12 pages, 7 figures, optimized for A4 paper. Partly biographical, partly historical review of subjects to which Priester contributed...

This link is to (popular) cosmology books, http://www.astro.ucla.edu/~wright/cosmobib.html Which would you buy/not ?

http://arxiv.org/PS_cache/astro-ph/pdf/0310/0310808.pdf uses the term "proper distance", but doesn't define it. Presumably this must be a standard defintion. So far, though, I have not been able to track down a definitive defintion (I'm still looking). My guess is that this distance is...

I want to buy Barbara Ryden's Cosmology book. Has someone read it already and could say a few things about it? On amazon it gets nice reviews but what do you think? thanks

Entropy, information and Omphalos cosmology Roger Penrose, in The Road to Reality, discusses the Second Law of Thermodynamics and the Universe’s entropy. He floats (section 27.13) an order-of-order-of magnitude argument that the entropy of our Universe has increased from mighty big (10^10^88)...

Gday, I'm currently doing a major yr 11 assignment on cosmology for physics. One of the questions in this assignment was about the historical developments of various models of the universe over time. I've mentioned the geocentric and heliocentric models but the question also asks about the...

Hi I'm new here, I found this forum while trying to plan my career in cosmology. So far to have a good career in this field you must have a Bachelor, a Masters, and a PhD. So far I know what college I'm going to go for my Bachelors, which is Angelo State University. I already have a four-year...

Whenever a diffuse gravitating system condenses into a stable and more compact object, energy must be removed from it. This is a consequence of the Virial theorem, which mandates that in a stable system of gravitating particles there must be a proportional balance between the magnitudes of...

Hi all, I'm going to spend my summer doing some self-study in the subjects which I'll be covering in the future and I think it'd be a great time to dive into relativity. I've had some education in special relativity but I've never dealt with general relativity. I'd like a good, thorough...

-> = implies Dark Energy -> Repulsion Inflation -> Repulsion Gravitation -> Attraction (Repulsion = Attraction -> Steady Region) & Euclidean Universe -> Light can travel on parallel lines that remain the same distance from each other :: matter, light, and energy maintaining present...

Is NASA doing anything to advance the science of cosmology? my personal veiw is that this agency is a total waste of money, money that could be spent, doing robust scientific cosmological related experiments, what do you think?

What are the (basic) problems with main stream theories of cosmology ? i do not want crackpotery, just what the people who work in or around the field think. I am unqualified to comment and will not, i hope moderators will keep this thead to the point.

i find the study of cosmology very fascinating and now contemplating to study it. But is it a wise choice? I mean, how practical is cosmology in everyday life? not that i really need it to be, I'm more than satisfied to have answers I've always been pondering about. and is employment hard...

Specifically LGC is dual to RS theory with an extra (large) time-like dimension, as reported by Parampreet Singh today in: http://arxiv.org/PS_cache/gr-qc/pdf/0603/0603043.pdf This is the first connection between loop quantum gravity and string theory that I am aware of. The need for an...

I am a high school student interested in cosmology and gr, qm, and mtheory. I find it fascinating to think about the origins of the universe. I need clarification on a 'simple' aspect of the gr theory. *Time is warped and slowed down (relative to another location) around greater masses *As...

http://arxiv.org/abs/astro-ph/0602500 Authors: Ari Brynjolfsson Comments: 8 pages, 4 figures, presented at APS April 2006 meeting We have previously shown that the type Ia supernovae data by Riess et al. match the prediction of the magnitude-redshift relation in the plasma-redshift...

Check this out Loop Quantum Cosmology http://www.arxiv.org/abs/gr-qc/0601085 Authors: Martin Bojowald A terrific paper. Frankly, I am awed by this work.

today Martin Bojowald posted a paper on Loop Quantum Cosmology http://arxiv.org/abs/gr-qc/0601085 it is over 100 pages long and has movies to illustrate more info on the "Rovelli's program" REFERENCE LINK THREAD here: https://www.physicsforums.com/showthread.php?p=888994#post888994 the...

If the universe is expanding/stretching, what is it expanding/stretching into? Is it nothingness? Or rather is it is 'nothingness' only in the sense that we cannot give it a word or a definition? Where did all the mass-energy in the universe came from? Did it came from nothing? Of course...

I am asked in a question to show that the friedman with k<0 equation can be solved by substituing a= b(1-cos(theta)) and t = c(theta- sin(theta). a is scale factor, t is time b,c are constants Can anyone outline the general procedure to go about solving this. I've tried...

confirm the Big Bang theory? I know that we currently have a lot of evidence to support it. But what I'm not sure of is why can't we see beyond the Planck Epoch 10^-43 or confirm that yes the universe did exist as a singularity beyond this point? And did this "singularity exist as some kind of...

This might be posted on the Cosmology Forum. But I think it's more likely to get answers here: 1. Is inflation as in the Big Bang coincident with compactification? 2. Is the compactification of 6 dimensions most likely or could other numbers of dimensions be just as likely? 3. I read that...

I sort of see philosophy as standing by itself in comparison to the other two subjects in question. I've found physics and cosmology to be inextricably linked in many ways. I was wondering if anybody had a recommendation regarding what to study first (even though I've technically already studied...

i was wondering what you guys thought would be the best think to major in for someone who wanted to go into cosmology. Especially in regard to relativity or quantum mechanics. Also, where do you guys think the best place to go for my undergrad is for the major you suggest

I would like to eventually like to pursue a career in cosmology. However, there is no specific undergrad that I have found that is specifily "Cosmology" the closest I seem to be is Astrophysics. My question, is Astrophysics the best major for someone how is interested in pursuing...