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### Cosmology FAQ

Quality answers to common cosmology questions
Jun25-11 09:50 PM bcrowell

# Cosmology

- The origin, evolution, and structure of the universe. Along with the eventual fate of the universe.
 Views: 380 Announcement: End of year contest, $75+$50 prize! Dec18-13 Meta Thread / Thread Starter Last Post Replies Views Pinned: Effort to get us all on the same page (balloon analogy) ( 1 2 3 ... Last) To have an enjoyable cosmo forum we needed a balance between mental freedom on the one hand and a shared knowledge... Sep12-13 02:51 PM GeorgeDishman 474 115,319 The new A20 tabular calculator lets you look at changing geometry out to about 88 billion years according to the... May19-13 12:45 PM Jorrie 56 17,755 Self Creation Cosmology ( 1 2 3 ... Last) After an abortive start in the new IR Forum I am beginning a new thread on the published theory of Self Creation... Apr28-07 04:48 AM Garth 127 15,244 http://arxiv.org/PS_cache/astro-ph/pdf/0310/0310808.pdf uses the term "proper distance", but doesn't define it. ... May7-07 03:47 PM MeJennifer 16 2,688 Is it by now conclusively established that the universe is made mostly of exotic dark matter and dark energy? I need... May4-07 05:15 AM oldman 45 4,849 What is the ratio of the scale factor now to the scale factor at the end of the inflationary era? Edit: In other... Apr30-07 07:51 AM pervect 10 6,668 The Big Bang Theory has the whole universe expanding from an initial size considerably smaller than an atoms nucleus.... Apr28-07 06:26 PM ukmicky 9 2,009 this is a case where it could be very helpful if someone (Pervect? Wallace? hellfire?) who has the numbers handy could... Apr25-07 12:14 PM marcus 4 3,381 If a star is spinning very fast before it collapses, then as it collapses it's going to spin faster, like a skater... Apr29-07 07:24 PM xantox 6 1,366 I'm an engineer, not a physicist, so you'll forgive my pre-uni knowledge of all things physics. I was discussing... Apr29-07 05:10 AM cesiumfrog 9 1,890 I am a newbie to cosmology, and have just finished reading "The first three minutes" by Weinberg. On page 76 he... Apr30-07 02:52 PM aludwig 7 1,560 I'm doing a project on dark matter and i've found some good information but I still haven't found any related... May2-07 03:27 AM Chronos 3 971 Hey guys, I've been wondering a lot about this Big Bang Theory, as I think it is terribly constructed. Anyways, I... May2-07 06:01 PM pervect 34 3,279 I understand that motion is relative and that everything is in motion. My Questions are : Is there such a thing... May19-07 02:06 AM zankaon 6 1,291 I would like someone to write to me the equation which shows the explicit dependence of the spectral index n on the... May1-07 05:49 PM emanaly 0 1,185 Universe or Multiverse? ( 1 2 3 ... Last) Defining what is/can be included in a description of what constitutes the universe is a frequent topic of interest.... May31-07 04:46 PM RussT 59 6,141 Ok this may sound silly but humor me . If there was an edge to our universe a sor of big expanding bubble ,is it... May7-07 02:32 AM pervect 4 4,139 Does the metric of the Friedmann model yield an unbouded universe? I mean, are the geodesics of this metric closed? Jun3-07 02:59 PM jal 29 3,413 I am confused about the currents status of knowledge in cosmology, I always thought that cosmologists believed the... May7-07 12:27 PM da_willem 2 3,220 This site: http://curious.astro.cornell.edu/question.php?number=575 , states that "Astronomers now have strong... May22-07 11:59 AM sunblock 19 2,969 The Einstein cross (G2237+030) shows 4 reasonably symmetrically spaced images of the very distant quasar, indicating... May15-07 11:24 PM Chris Hillman 3 2,032 Age of the universe... ( 1 2 3 ... Last) I've heard stated by experts that the approximate age of our universe is about 13.5 billion years of so. The thing... May23-07 05:01 PM BoomBoom 54 6,881 Hi. If I have got it all right the latest measurements of light from very distanced super novas tells us that the... May15-07 11:29 PM Chris Hillman 3 1,242 Today's Astronomy picture of the day is visually appealing as well as scientifically revealing. ... May31-07 07:46 AM Jimmy Snyder 16 2,274 Edit: Thread started at the same time as Garth's on the same topic, go here instead! May18-07 03:22 AM Wallace 2 2,228 I was wondering, if dark matter (DM) halos are spherical in nature and increase in density as a function of distance... May21-07 03:19 AM Wallace 2 1,255 I looked briefly at the thread herein regarding "Simulating the universe" but it did not appear to involve the future... May20-07 08:01 PM marcus 3 1,730 Is their structure so "great" that they are just a natural, or inevitable, outcome of the mass/energy burst that took... May25-07 01:45 PM Phobos 3 1,336 Why would gravitational waves be generated from the merging of two black holes or other types of mergers? What is... May21-07 05:42 PM Chris Hillman 3 1,533 Ashtekar's team at Penn State has been running cosmological BOUNCE simulations on the computer, studying many... May23-07 12:07 PM hellfire 19 2,118 Recently I saw a magazine which published an article on multiverse, where our universe is just one of the many... Jun6-07 10:30 AM hellfire 1 1,386 Hey, can anybody tell me what the estimate is on the mean mass of a particle in the interstellar medium? I would guess... May23-07 11:26 AM marcus 1 1,244 Time? I am sure that there is hundreds of reasons why this could not be possible but, it seems to me that there is... May28-07 04:01 PM Integral 9 1,877 this just out: a survey of efforts to detect DM particles. http://arxiv.org/abs/0705.3345 Direct Dark Matter... May23-07 08:49 PM marcus 0 1,108 What exactly is the relevance of squeezed quantum states to the primordial matter perturbations in cosmology... May24-07 08:28 PM smallphi 0 1,106 Hi. I would like to discuss this: http://www.sciencedaily.com/releases/2007/05/070524094126.htm "Now, physicists... May26-07 03:50 AM Chronos 9 1,764 What percent of baryonic matter is antimatter? I am well aware that DM accounts for most "matter" and that there... May30-07 02:16 AM Wallace 1 2,173 I found the following definition for the Hubble Radius: The radius of the Hubble sphere (Hubble radius) is defined... Jun5-07 09:15 AM hellfire 8 5,191 Do antistars absorb photons? I read Feynman's Book, "QED - The Strange Theory of Light and Matter", there a while... Jun5-07 07:09 AM Nasher 6 2,404 This question concerns Omega(matter+dark+lambda). We take into account protons(baryons), electrons(leptons),... Jun1-07 02:02 AM Wallace 5 1,349 How about this idea... With regards to this thing called, the arrow of time! Could the universe have different... Jun6-07 02:16 AM Chronos 6 1,537 I need a good book on Inflation theory to start studying . Does anyone know a good book written on inflation theory?... Jun4-07 09:29 AM hellfire 3 1,749