It is necessary to carry out spectral observations of nearby stars of the Galaxy disk. The radial velocities of stars along the radius vector of the Galactic center will be equal to zero, and radial velocities in the direction of the apex antiapex of galactic rotation will also be absent. In the directions shifted by 45 ° from these directions, on the contrary, the radial velocities will be maximum.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.