MOND - dark matter - modified newtonain dynamics

Note that the most recent version of this page has moved with its author to Case Western Reserve University.

Welcome to the MOND pages

The Modified Newtonian Dynamics (MOND) s a scientific theory proposed by Moti Milgrom as a solution to the missing mass problem in extragalactic astronomy. Rather than invoking some invisible form of dark matter, it hypothesizes a subtle change to the effective force law at extremely low accelerations (< 10-10 m/s/s).

The basic issue, in brief, and what's at stake.
The Dark Matter Tree (small | large | formal | new tree with pictures) showing the empirical roots of the mass discrepancy problem and the many proposed branches of solutions.
Why consider MOND? | Cosmic fallcies | Attitude
A comparison of how ΛCDM and MOND fare in various observational tests.
Frequently Asked Questions
The External Field Effect in MOND and its explanation

Scientific Literature
Extensive list of the literature concerning MOND, complete with links to the actual papers when available, and the occassional commentary.

Funding: please visit Science Bucks

Material concerning Dark Matter
Experimental Searches for dark matter - a perpetual quest?

Insightful article on the difficulty of objectivity, even in science.
The Great Dark Matter Debate (11/18/2010 Bethe Colloquium, Bonn University, Germany).
Also available at this local link.
The Blind Men and the Garden.

MOND in the news
An interesting discussion at the Flamsteed Astronomy Society 5/14/2012
Gas Rich Galaxies Confirm Prediction of Modified Gravity Theory press release 2/22/2011
Viewpoint for PRL by Masters & Spekkens
Original news articles: BBC | Science | Nature | motherboard | Science & Vie (in French)
Other articles: io9 | redOrbit | PhysOrg | ScienceDaily | technologijos (in Lithuanian)
The blogosphere reacts:
User's Guide to the Universe | The Dayside | Cosmic Variance | Starts with a Bang | Weizman Wave | Particle Decelerator
Trialogue with Rainer Plaga and Sean Carroll.
Some remarks on cognitive dissonance

Rebuttal of criticisms made by Foreman & Scott and N. Gnedin.

Further material, including older publications in the popular press and other MOND related sites.

Material written at the Popular Level
Philosophical aspects of the debate over Dark Matter and MOND
Sure to provide fodder for sociologists and historians of science for decades to come.
A popular perspective [HTML] | [PDF]
written for Astronomy Now (January 2002)
There have been a number of good, popular level reviews lately -
see the appropriate section of the literature page.
Milgrom's article for Scientific American (August 2002)

Slides from talks related to MOND
Review talk for Modifed Gravity Approaches to the Dark Sector, June 2010
Colloquium given at DTM, April 2008
Colloquium given at TRIUMF, February 2008
Physics department colloquium given at George Mason University, April 2007.
Review talk given at the Alternative Gravities and Dark Matter Workshop, April 2006.
Physics department colloquium given at the University of Rochester, April 2006.
Review talk given at the interdisciplinary conference Dark Matter in the Universe, October 2005.

Material related to the Dynamical Evidence
Comparison of MOND and Dark Matter | New table (11/2011)
Includes a table itemizing various observational tests and how each fares.
Example of a MOND fit to a rotation curve.
Comparison of MOND and CDM fits to the rotation curve of NGC 1560.
Lots and lots of fits (2003).
These are plotted log(V)-log(R) for data with velocity errors < 5%.
Points with error bars are the data; red lines are the fits; light blue lines are the Newtoinian stars+gas.
Residuals of MOND fits (3/2012)
Predictions made by Milgrom in 1983 which were subsequently confirmed (in 1998)
A MOND fit to the rotation curve of a low surface brightness galaxy.
Mass-to-Light Ratios and Stellar Populations
Remarkably reasonable.
Roster of galaxies which have been used to test MOND:
MOND performs well in the Milky Way, providing detailed information about the surface density profile.

N-body computations
Modelers beware: implementing MOND is not a one line change to standard particle-pushing codes. Chris Mihos explains why. (The inertial modification is inherently nonlocal.) [See also a more sober write-up.]
Other numerical approaches are necessary. For example, Brada's thesis; Ciotti, Londrillo, & Nipoti; Tiret & Combes.

Material related to the Cosmic Microwave Background
BBN: Comparison of the density of baryons in ΛCDM & MOND.
2006: The Third Peak in TeVeS (April 2006).
2006: WMAP finally reports new data (March 2006).
2005: BOOMERanG reports new data from its 2003 Antarctic flight (Aug. 2005).
The WMAP second-year data are a year and half late and counting...
2004: The WMAP second-year data are late.
2003: No-CDM & WMAP (Feb. 2003).
WMAP 1st:2nd peak amplitude ratio bang on the No-CDM prediction.
WMAP polarization detection confirms the prediction of early reionization.
The critical third peak remains ill-constrained.
2001: How the No-CDM prediction fares with DASI and updated (in May, 2001) BOOMERanG CMB data.
2000: No-CDM prediction realized in BOOMERanG microwave background data.
Associated press release, Sept. 27, 2000.
1999: No-CDM model provides best-guess prediction for CMB in a MOND universe.
Strictly speaking, only the shape of the power spectrum is predicted in the absence of CDM. This represents MOND only under the ansatz that a MOND version of GR is identical to standard GR in the early universe. More properly, this is a test for the existence of non-baryonic dark matter, and says nothing directly about MOND.

Material related to the Bullet Cluster
The missing baryon problem in MOND and ΛCDM.
Comments on the Bullet Cluster claim to require dark matter.
The full text of my reply to press inquiries (from which published quotes were extracted).
Paper by Angus et al. fitting the new data.
Preprint examining the collision velocity of the clusters. This is more naturally understood in terms of MOND than CDM. [Published in MNRAS (2008) 383, 417]
The bullet cluster is also a problem for ΛCDM.
Milgrom's comments on the Bullet Cluster
An unsolicited, independent perspective
Related talks by Angus: PPT | text
The collision velocity of the bullet cluster in CDM and MOND.
A counter-example to the bullet cluster - Abell 520.
The dark matter ring in cluster 0024+17.

Material related to Tidal Dwarfs

Can tidal dwarfs falsify dark matter?

MOND - dark matter - modified newtonain dynamics
MOND - dark matter - modified newtonain dynamics
MOND - dark matter - modified newtonain dynamics
MOND - dark matter - modified newtonain dynamics

Link to further material, including other MOND related sites. MOND - dark matter - modified newtonain dynamics
MOND - dark matter - modified newtonain dynamics
MOND - dark matter - modified newtonain dynamics
MOND - dark matter - modified newtonain dynamics
MOND - dark matter - modified newtonain dynamics
MOND - dark matter - modified newtonain dynamics
MOND - dark matter - Modified Newtonain Dynamics
MOND - dark matter - modified newtonain dynamics

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