10th February 2017.  Indranil Batik - St. Andrews University

"Thinking Outside the Dark Matter Box - Modified Gravity in Plane Sight". Understanding galaxies without dark matter
The mainstream, conventional theory of the universe is that most of the mass is in the form of invisible, so-called ‘dark matter’, which makes its presence felt in effects such as the rotations of stars in galaxies and the movements of galaxies in clusters.  However, despite decades of theorising and searches, we are no closer to explaining or finding dark matter.
An alternative theory is that our understanding of gravity may be insufficient, particularly on quantum scales and at very low accelerations or energy densities.  We know gravity must operate at these scales, but we don’t yet have a good, workable theory of how it should do so.
Our speaker, Idranil, presented some of the latest research into new theories of gravity in these regimes, and showed a number of pieces of evidence that could explain not only the effects attributed to dark matter, but in some cases was a better fit to observations.  Additional observations, such as the motions of dwarf galaxies around the Milky Way and Andromeda, are also well explained by modified gravitation, but not by the dark matter model.
Our thanks to Idranil for a highly informative and detailed talk.

Following a short break for refreshments our Director of Observations, Jim Barber, reminded us that during the summer there would be the usual "Saturday Stars" open days at the Mills Observatory for families and that DAS members usually attended with Solar telescopes weather permitting.  Dates would be posted here in due course.
Indranil Batik