Spiral galaxies rotate too fast. If they would only consist of the visible (baryonic) mass we observe in them and Newton's Law of gravity is correct, then they would not be stable and should quickly fly apart. That they don't has been one of the first indications that the galaxies (and the Universe as a whole) either contains large amounts of additional but invisible "dark matter", or that the laws of gravity don't hold on the scales of galaxies. One... Read more
ABOUT Marcel S. Pawlowski
I am a postdoc at the Department for Astronomy of Case Western Reserve University in Cleveland, OH. My work there revolves around tidal dwarf galaxies – second-generation galaxies forming from the debris of galaxy collisions – and their use for testing models explaining the dark matter phenomenon.
During my PhD studies in Bonn (in Pavel's group|) my research concentrated on the phase-space distribution of the Milky Way's satellites (dwarf galaxies, globular clusters and tidal streams), their possible formation scenarios (in particular tidal dwarf galaxies) and tests of cosmological models on (cosmologically) small scales.
My research interests are complemented by my interest in the philosophy of science and in science outreach. You can follow me on Twitter (@8minutesold) or find out more about me and my photography on my website (http://marcelpawlowski.com).
Marcel S. Pawlowski: All Posts
In case you, like me, have missed Pavel Kroups's recent talk at the Joint Astronomical Colloquium in Heidelberg, you now have the opportunity to watch a movie of the event and download the slides. The movie is quite long (more than an hour), but it is worth watching it to the end. While the talk is titled "The vast polar structures around the Milky Way and Andromeda", Pavel talks about much more, starting with tidal dwarf galaxies and ending with... Read more
On Wednesday, the Large Underground Xenon Detector (LUX), a direct detection experiment for Dark Matter, has announced its first results. Before the announcement there was the usual excitement, with Nature News titling “Final Word is near on dark-matter signal”. So, has Dark Matter finally been detected? Some previous experiments had reported possible detections already. For example, the Cryogenic Dark Matter Search (CDMS) recently presented an impressive number of 3 possible dark matter events (compared to 0.7 they estimated to be... Read more
Following the recent incident, we and the SciLogs team decided to invite a renown colleague to write a guest blog post. Thinking about possible guest bloggers who are experts in the field of cosmology and approach theories such as MOND with the necessary scientific skepticism, we arrived at Scott Dodelson as one candidate. Scott is a very well-respected cosmologist. He is a scientist at Fermilab and a professor in the Department of Astronomy and Astrophysics and the Kavli Institute for... Read more
(Continuation of the series A-E) There has been an unsuccessful attempt to close down The Dark Matter Crisis. Here is the story (and an email by Jim Peebles): UPDATE: The guest post is now online. As regular readers of our blog know, and first-time readers may be able to guess from this blog name, Pavel and I mostly write about the problems and shortcomings of the dark matter hypothesis. One aspect of our research is to test dark matter models... Read more
Dwarf galaxies, that is galaxies less massive than a few billion solar masses, are expected to be formed through two processes. They might either be the luminous components of small dark matter halos, formed early in the universe when gas fell into the potential well of those halos. These dwarf galaxies are called primordial dwarf galaxies (PDGs) and are expected to be dominated by their dark matter content. The other formation mechanism is a process observed even in the present-day... Read more
Pavel and I have been too busy to blog for a while (my excuse being that I am in the final stages of my PhD studies). This is also why we did not announce this sooner: Our blog has moved from SciLogs.eu to SciLogs.com. The new site provides an improved blogging system and maybe more international visibility, as well as a pleasant neighborhood of science bloggers. The new URL for "The Dark Matter Crisis" is http://www.scilogs.com/the-dark-matter-crisis/. All future articles will... Read more
Today's issue of Nature contains a very exciting study by Rodrigo Ibata et al. which might be a game-changer in the research areas of galaxy formation and near-field cosmology. It is titled “A vast, thin plane of corotating dwarf galaxies orbiting the Andromeda galaxy” and already now should be seen as a candidate for the most-exciting paper of 2013. UPDATE Jan. 4th: The article is now also available on the arXiv. Pavel Kroupa and I have been waiting for this... Read more
We are now on our way to the 13th Marcel Grossmann Meeting in Stockholm. The meeting of physicists and astronomers covers General Relativity, Gravity and relativistic field theories and is held every three years (since 1975) in different cities. It is named after Marcel Grossmann, who was a Swiss mathematician and a collaborator of Einstein in his work on general relativity. Following his recent review paper “The dark matter crisis: falsification of the current standard model of cosmology”, Pavel has... Read more
We have just returned from a talk by the Bethe colloquium. Erik Verlinde from the university of Amsterdam spoke about “Dark Matter, Dark Energy and the Emergence of Gravity ”. Verlinde is a dutch theoretical physicist working on string theory and gravity. He became very famous for his theory of entropic gravity and was awarded the Spinoza Prize for his work. In his talk, he showed that his approach can not only reproduce the MONDian behavior of the different kinds... Read more