Differential rotation of the Milky Way Differential rotation

disk galaxies don t rotate solid bodies, rather rotate differentially. rotation speed function of radius called rotation curve, , interpreted measurement of mass profile of galaxy, as:

v

c


(
r
)
=




g
m
(
<
r
)

r





{\displaystyle v_{c}(r)={\sqrt {\frac {gm(<r)}{r}}}}

where

v

c


(
r
)
,


{\displaystyle v_{c}(r),}

rotation speed @ radius



r


{\displaystyle r}






m
(
<
r
)
,


{\displaystyle m(<r),}

total mass enclosed within radius



r


{\displaystyle r}