This tongue-in-cheek quote is a statement of the obvious, at least for the 90+ years since Hubble established that galaxies are stellar systems comparable to and distinct from the Milky Way. There’s interstellar gas and dust too, and I suppose for nearly half that time, people have also thought galaxies to be composed of dark matter. But you can’t see that;

People seem to like to do retrospectives at year’s end. I take a longer view, but the end of 2020 seems like a fitting time to do that. Below is the text of a paper I wrote in 1995 with collaborators at the Kapteyn Institute of the University of Groningen.

A unique prediction of MOND One curious aspect of MOND as a theory is the External Field Effect (EFE). The modified force law depends on an absolute acceleration scale, with motion being amplified over the Newtonian expectation when the force per unit mass falls below the critical acceleration scale a0 = 1.2 x 10-10 m/s/s. … Continue reading Statistical detection of the external field effect from large scale structure →

This post is a recent conversation with David Garofalo for his blog. Today we talk to Dr. Stacy McGaugh, Chair of the Astronomy Department at Case Western Reserve University. David: Hi Stacy.

The following is a guest post by Indranil Banik, Moritz Haslbauer, and Pavel Kroupa (bios at end) based on their new paper Modifying gravity to save cosmology Cosmology is currently in a major crisis because of many severe tensions, the most serious and well-known being that local observations of how quickly the Universe is expanding … Continue reading Big Trouble in a Deep Void →

This post is adopted from a web page I wrote in 2008, before starting this blog. It covers some ground that I guess is now historic about things that were known about WIMPs from their beginnings in the 1980s, and experimental searches therefore.

I have been busy teaching cosmology this semester. When I started on the faculty of the University of Maryland in 1998, there was no advanced course on the subject. This seemed like an obvious hole to fill, so I developed one.

At the dawn of the 21st century, we were pretty sure we had solved cosmology.

In the previous post, I wrote about a candidate parent relativistic theory for MOND that could fit the acoustic power spectrum of the cosmic microwave background (CMB). That has been a long time coming, and probably is not the end of the road.

The missing mass problem has been with us many decades now. Going on a century if you start counting from the work of Oort and Zwicky in the 1930s. Not quite a half a century if we date it from the 1970s when most of the relevant scientific community started to take it seriously.

A Philosophical Approach to MOND is a new book by David Merritt. This is a major development in the both the science of cosmology and astrophysics, on the one hand, and the philosophy and history of science on the other. It should be required reading for anyone interested in any of these topics.