Dynamical friction illustration (IMAGE)
Caption
Dynamical friction. The panels depict sparse areas of the universe with dark colour and dense areas with light colour. The upper panels show the density around a galaxy if the galaxy's gravity bends (left) or does not bend (right) the trajectories of dark matter particles. The lower panel shows the difference between them, or how the galaxy affects the distribution of dark matter. The arrows represent the acceleration caused by the overdensity behind the galaxy, from which the friction on the centre of the galaxy is deducted. Since the arrows have different directions and strengths in different areas, the tidal forces are able to change the shape of a galaxy.
Credit
Rain Kipper
Usage Restrictions
CC BY-SA Creative Commons Attribution-ShareAlike International license
License
Original content