Into Astro 42:
Galaxy Rotation Curves
The LCDM cosmology is widely regarded by the scientific community nowadays as the leading model for the universe. Specifically, in order to explain the discrepancy in galaxy rotation curves, it assumes the existence of dark matter halos around each and every galaxy. However, various recent-years fundamental issues have led some astrophysicists to be uncomfortable with the current paradigm. The number of "cracks" in the current model became too large to be ignored.
These astrophysicists feel it's about time to seriously explore alternatives.
This site presents one of the recent leading alternatives in the domain of rotation curves: the effects of inertial forces on the dynamics of spiral galaxies. That is, a new approach to handle the discrepancy without modifying gravity or using dark halos. The interested reader may also visit our publications section. Useful explanations and discussions on the discrepancy, video demonstrations of rotating galaxies, an historical overview of the subject and Tools to model mass components of spiral galaxies are also available. Have any question? Don't hesitate to contact us.
The 50-years discrepancy in Galaxy Rotation Curves is in actuality a mismatch between the observed rotational velocities in galaxies and our predictions regarding these velocities. It is customary to plot those velocities as a function of the distance from the galactic center, as can be seen in the graph.
In order to develop some intuition, let's take a look ...
A NEW APPROACH
Velocity is relative. When one states: "I am moving at a rate of 2 meters per second", one actually assumes that there is some reference point, relative to which he is changing the distance. In exactly the same way, when an astronomer states: "this gas cloud is rotating around the galactic center at a rate of 80 Km/sec", she actually means that she has been supplied with a well defined frame of reference, relative to which this value is valid. The observed values in rotation curves are also valid only with respect to some specific frame of reference. The only question is whether this frame is an inertial one. Why is it relevant? Because currently, when fitting rotation curves, astrophysicists take this quality for granted. Modeling a rotation curve (from the corresponding mass distribution) implicitly relies on this assumption.