Related Experiment Video
Updated: Jun 18, 2025

Setting Limits on Supersymmetry Using Simplified Models
Published on: November 15, 2013
Six spiral galaxies lacking dark matter
Cheng-Yu Chen1, Chorng-Yuan Hwang2
1Graduate Institute of Astronomy, National Central University, Taoyuan, 320317, Taiwan. m969004@gm.astro.ncu.edu.tw.
Abstract:
Dark matter is believed to be the essential building blocks of galaxy formation. While instances of galaxies lacking dark matter have been observed, these occurrences are typically linked to specific formation mechanisms, making them stand out as unique cases. In spiral galaxies, the presence of flat rotation curves is a common observation, indicating the need for dark matter to support these dynamics. However, the galaxies displaying minimal or no dark matter are likely not exceptional cases. We report several spiral galaxies where the flat rotation areas exhibit an average dynamical to baryonic mass ratio value of . The low dynamical to baryonic mass ratios indicate that the kinematics of these galaxies can be supported by their baryonic mass only. The existence of spiral galaxies devoid of dark matter suggests that, in specific scenarios, the influence of dark matter on galaxy formation may not be as universally essential as previously believed.
Related Concept Videos
Detection of Black Holes
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...
Gravitation Between Spherically Symmetric Masses
Schwarzschild Radius and Event Horizon
The minimum speed required to launch a projectile from the surface of an object to which it is gravitationally bound so that it eventually escapes the object’s gravitational field is called the escape velocity. The escape velocity is independent of the mass of the object. Merging the idea of escape...
Reduced Mass Coordinates: Isolated Two-body Problem
Gauss's Law: Planar Symmetry
Gauss's Law: Spherical Symmetry

