Dynamics of Local Group galaxies: Evidence for a past Milky Way–Andromeda Flyby?

Posted 9 July 2016 by Marcel S. Pawlowski

The following is a guest post by Indranil Banik. Indranil is a PHD student at the University of Saint Andrews, part of the Scottish Universities’ Physics Alliance. He was born in Kolkata, India and moved to the UK with his parents a few years later. Indranil works on conducting tests to try and distinguish between standard and modified gravity, especially by considering the Local Group. Before starting his PhD in autumn 2014, he obtained an undergraduate and a Masters degree from... Read more

The Weizmann Experience: discussions on the future of cosmology

Posted 15 March 2016 by Pavel Kroupa

Together with Francoise Combes, who was recently appointed as a professor in the most prestigeous institution in France, Le College de France, and Benoit Famaey, who is an expert on Milgromian dynamics and its deeper foundations (e.g. Famaey & McGaugh 2012), we were invited by Mordehai (Moti) Milgrom to spend a whole week at the Department of Particle Physics and Astrophysics in the Weizmann Institute in Rehovot, Israel. A link to the video (dubbed in English) of the inaugural lecture... Read more

The detection of gravitational waves, predictions, MOND and my visit to the Weizmann Institut in Rehovot, Israel

Posted 3 March 2016 by Pavel Kroupa

The announcement on Feb.11th, 2016, that gravitational waves have been detected is a sensation and it is indeed rather incredible to imagine that space-time is constantly wobbling with and around us all the time because of some cosmic events, as is expected to be the case in Einstein's theory of general relativity. Imagine a wave comes though and everything gets distorted. Obviously, we will not measure a change,  since also the ruler is distorted. So the way LIGO works is... Read more

First Workshop on Progress in Modelling Galaxy Formation and Evolution in Milgromian dynamics — first results achieved with the Phantom of Ramses (PoR) code

Posted 28 July 2015 by Pavel Kroupa

[Note: This web-page is being updated continuously: current status: 26.09.15] LOCATION and TIME: Observatoire astronomique de Strasbourg, Universite de Strasbourg, CNRS UMR 7550, Sept. 21st - 25th 2015 Below are provided 1.BACKGROUND/MOTIVATION 2.HOW TO REGISTER 3.PARTICIPANTS 4.HOTELS 5.PROGRAMME 6.PHANTOM WIKI ORGANISERS: Benoit Famaey (Strasbourg) and Pavel Kroupa (Bonn) 1.BACKGROUND / MOTIVATION: Galaxy-scale data seem to be in accordance with the hypothesis that the extrapolation of Newtonian gravitation by orders of magnitude below the Solar system space-time curvature breaks down completely,... Read more

Can one say anything, even the most obviously wrong things, to discredit an alternative to the standard model? An incident: cosmology at CalTech

Posted 20 March 2015 by Pavel Kroupa

The answer to the question posed in the title is  "Apparently, and sadly, yes." In previous contributions we have blogged about sociological problems that arise when attempting to do research in non-standard cosmological frameworks (for example the attempt at closing down "The Dark Matter Crisis"). Early 2015 an incident occurred which is a contemporary example of this, but which may also possibly be a serious case of scientific misconduct. It appears to be an aggressive act in an attempt to discredit new... Read more

Dark Matter in the innermost regions of the Milky Way?

Posted 20 February 2015 by Marcel S. Pawlowski

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

Pavel Kroupa on “The vast polar structures around the Milky Way and Andromeda “

Posted 22 November 2013 by Marcel S. Pawlowski

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

LUX: Results from another direct (non-)detection experiment for Dark Matter

Posted 1 November 2013 by Marcel S. Pawlowski

WIMP Dark Matter cross section

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

The Planck Results on the Cosmic Microwave Background

Posted 22 April 2013 by Pavel Kroupa

Guest contribution by Behnam Javanmardi Prologue by Pavel Kroupa: The much awaited Planck results on the CMB have been published recently. The results are consistent with those arrived at by using Wilkinson Microwave Anisotropy Probe (WMAP) measurements. This agreement is excellent news, because it means that the two missions are consistent and thus the Planck data enhance our confidence in what we know about the CMB. But, what do the results mean in terms of our physical understanding of the... Read more

Scott Dodelson on dark matter and modified gravity (guest post)

Posted 9 March 2013 by Marcel S. Pawlowski

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