Links to Cosmology and Cosmic Structure Evolution

Ned Wright's Cosmology Calculator, the advanced version, and yet another version that computes z for given light travel time (for astronomers who `hear about it first' from a press release)
iCosmo: Interactive Cosmological Tools; and yet another cosmology calculator with photometric quantities.

Ned Wright's Cosmology Tutorial
Ned Wright answers frequently asked questions
Ned Wright takes on a recent dubious alternate "hypothesis" to the Big Bang
Ned Wright takes on a dubious alternative model for the cosmic background radiation
Read why tired light is tired and why the cosmic microwave background cannot be starlight (or even a sum of blackbodies)
Ned Wright takes on other dubious alternate "hypotheses" to the Big Bang
Ned Wright's list of other good cosmology sites
Is the Universe Younger than its Oldest Stars?
Sten Odenwald's Cosmology Essays

Here is a page that discusses the so-called Quasar redshift controversy

Sean Carroll (the astrophysicist) and John Horgan (the science writer) discuss (video) the nature of big bang cosmology, and whether models such as the "Inflationary Scenario" are scientific. Wonderfully illuminating! Here are 3 others with Sean Carroll and others: 1, 2, 3. Especially recommended for the beginner.

Understanding an expanding universe, and its many distances. Is there a center to the universe?
Lots of questions on cosmology (Big Bang, expanding universe) answered from links at this web page
After reviewing previously suggested models of the universe, Sten Odenwald lists 16 Observational facts supporting the Big Bang Theory
And here are a few more from Ned Wright.
An extensive discussion of the Big Bang Theory and observational evidence thereof.

An article from the popular science magazine, Scientific American, discussing several common misconceptions of the Big Bang Theory.

Wikipedia has a nice set of pages on and links to topics on Redshifts, Physical Cosmology, the Universe, the Big Bang, the Observable Universe, the Equation of State, the Metric Expansion of space, the FLRW metric, the Friedman Equations, and Distance Measures in Cosmology.

What is meant by "expanding universe"? See also here and here (the latter and references therein are bit more technical). A discussion of these issues can be found at the Cosmic Variance blog (read also the extensive comments that follow).

Cosmic Variance addresses the status of dark matter in several blog articles by Sean Carroll: 1, 2, 3, 4, 5.

Open Questions in Physics - really neat discussion of some really cool questions, including some in cosmology.

The Cosmology Primer - a non-technical overview of what we know about our universe (Sean Carroll)

The Kavli Institute for Cosmological Physics Education and Outreach
A Knowledgebase for Extragalactic Astronomy and Cosmology
A nice html slide presentation on modern studies of cosmology
WMAP's page on an Intro to Cosmology 
A cosmology tutorial from UC Berkeley
Links to the full set of University of Chicago Compton Public Lecture Series; many are on astrophysical topics

An Introduction to Cosmology
And still another tutorial - fairly high level, this one
Cambridge University Cosmology Group tutorials
Chapter 1 of Peacock's book on Cosmology
Eric V. Linder's First Principles of Cosmology
Berkeley University's Cosmology Education web pages
A tutorial on the Large Scale Structure of the Universe; some cosmology here, too.
Advanced undergraduate and graduate student level tutorials in General Relativity and Cosmology (Sean Carroll)
A gentle undergraduate level tutorial on cosmology and this is another.

The Wilkinson Microwave Anisotropy Probe: measuring the light of the Big Bang
Max Tegmark's pages on Precision Cosmology, and the cosmic microwave background (his movies are cool)
A great set of links on the Cosmic Microwave Background - though a bit technical
An introduction to the Cosmic Microwave Background - for beginners
A brief, yet excellent introduction to the formation of acoustic oscillations which led to the formation of large scale structure

A tutorial on the Cosmological Constant
"Cosmology: A Research Briefing"
High redshift supernova/supernova cosmology project pages

Java page: light element nucleosynthesis dependence upon the baryon/photon ratio
A tutorial on the Dark Matter problem
A really nice page demonstrating strong evidence for cold dark matter as observed in the "Bullet" galaxy cluster

Cosmos in a Computer
Galaxy Gallery Page IV: The Movies
Pictures and Movies of simulations of structure formation in the universe
Center for Cosmological Physics pages of simulations of structure and galaxy formation
Ab initio Simulations of the Formation of the First Star in the Universe (Tom Abel)
Simulations of the First Stars and Galaxies at the End of the Dark Ages
Resolving the formation of protogalaxies: here and here (John H. Wise, et al.)

Hypothetical scenario of the merging of the Milky Way and Andromeda galaxies 3 billion years hence
Simulations (movies thereof) of galaxy collisions, galaxy evolution, and structure formation by John Dubinski and Josh Barnes.

John Dubinski's page Gravitas: A Universe in Motion - lots of simulations of galaxy collisions and cosmic structure, set to music!
A nifty do-it-yourself double-galaxy collision simulator (low resolution, Javascript).
GALMER: a detailed, do-it-yourself double-galaxy collision simulator
GALFORM: Caltech / University of Durham galaxy formation model.

The Virgo and Hubble Volume Consortia:  (UK,Germany): 10 megaparticle and 1 gigaparticle simulations of structure formation; more numerical simulations of large scale structure and galaxy formation are found here, here, here, and here.
The Millennium Simulation Project. Millenium II and the MICE Simulations.

Another page with simulations of galaxy interaction and large scale structure formation
Via Lactea - A Milky Way dark matter halo evolution simulation
Nick Gnedin's gallery of numerical simulations of large scale structure formation
Hubble Deep Fields Homepage, and sites that allow you to click on a galaxy and get its redshift in the HDF North and South; see also this site. Images and text of the Hubble Ultra Deep Field (Sept.2003-Jan.2004) can be found here and here. Ned Wright's website allows you to flick the ACS and NICMOS images back and forth. This site lets the user click and drag a green circle to zoom into the Hubble Ultra Deep field.

Cutting Edge research in search of the First Galaxies

A map of the known galaxy superclusters within 2 billion light years.
Astronomer Brent Tully's neat public outreach pages on Large Scale Structure of the universe.

My set of links to tutorials related to Special and General Relativity Theories.

The Distance Problem in an expanding universe...

The vertical axis gives the distance to a galaxy in billions of light years (two black curves) or the lookback time in billions of years (red curve) for the cosmological parameters presently thought to govern the expansion of the present universe, as functions of the galaxy redshift, z. The lookback time measures how long light we observe now has been traveling - that is, how long ago the light we see observe now left the galaxy. A lookback time of 10 billion years means that we observe the galaxy as it was  10 billion years ago. Or, in other words, the lookback time is how long the light from a distant galaxy we observe now took to travel from there and then to here and now. The distance at the "cosmic now" (by observers at rest relative to the Hubble flow, i.e., comoving observers) is the radial co-moving coordinate distance (equal to the proper distance in a spatially flat geometry), and appears in the Hubble Relation, vrec = Hod.  The "distance then" is sometimes called the emission distance, and is a measure of how far away the galaxy was then when the light we see now left the galaxy. The ratio of these two distances, radial co-moving coordinate to emission distance, is simply 1+z for spatially flat geometries. For example, a galaxy with a measured redshift of 1.0 was 5.5 billion light years away at the time of emission of the light we see today, is now 11 billion light years away, and we observe it now as it was 7.9 billion years ago. Notice that the emission distance never exceeds approximately 5.89 billion light years near a redshift of 1.65, and then diminishes at greater redshift. This distance asymptotes toward zero at infinite redshift, meaning that all objects we now can observe were once relatively near to us (although you should keep in mind that the first galaxies likely began forming between redshifts of 30 and 10). This emission distance can in principle be measured by comparing the angular sizes of a class of objects of similar physical size, and so it is often called the angular diameter distance. The distance now asymptotes to about 47.9 billion light years, meaning that objects that have ever been above our cosmic horizon are now no further away than this in curved space-time. The lookback time, of course, aysmptotes to the present age of the universe at very large z; here 14 billion years (blue line). At very small z, d(now), d(then), and c x t(lookback) are very nearly the same, as expected. This last one, c x t(lookback), does not actually pertain to any useful distance to the galaxy in an expanding universe, but is unfortunately quoted as THE distance in the mass media. What should be said instead is that we observe the galaxy now as it was t(lookback) years ago.  Still confused? That's ok, but now try this link, and Wikipedia has an excellent article, as well. All points in the above graph and mentioned here were generated courtesy of Ned Wright's cosmology calculator (the advanced version here). Generate your own plot at iCosmo.

Kirk Korista
Professor of Astronomy
Department of Physics
Western Michigan University
Kalamazoo, MI 49008-5252
last updated:  10 March 2011
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