Subject: Is the Sun leaving the Milky Way

I read a middle school level science book talking about the sun, it says that 
the sun is circulating the Milky Way center with a speed of 250 km/s, and at 
the same time it is flying to the direction of M13 cluster with a speed of 20 
km/s. It does not say if the M13 is closer or farther to the center of Milky 
Way than the sun. If M13 is closer than the sun, then the sun is moving closer 
to the center of Milky Way, or the sun is moving way from the Milky Way if M13 
is farther than the sun. It is really confusing. Is the M13 cluster a member of 
Milky Way?

Re: Is the Sun leaving the Milky Way