 This black hole is suspected to be Sgr A*, with a mass of 4.2 × , where is the solar mass.Proper motions of the galaxies in the Local Group are discussed in detail in Röser.In 2005, the first measurement was made of the proper motion of the Triangulum Galaxy M33, the third largest and only ordinary spiral galaxy in the Local Group, located 0.860 ± 0.028 Mpc beyond the Milky Way.