Kinematic characteristics of the Milky Way globular clusters based on
  Gaia DR-2 data
  Using the data from Gaia (ESA) Data Release 2 we performed the orbital
calculations of globular clusters (GCs) of the Milky Way. To explore possible
close encounters (or collisions) between the GCs, using our own developed
high-order phi-GRAPE code, we integrated (backward and forward) the orbits of
119 objects with reliable positions and proper motions. In calculations, we
adopted a realistic axisymmetric Galactic potential (bulge + disk + halo).
Using different impact conditions, we found four pairs of the six GCs that may
have experienced an encounter within twice the sum of the half-mass radii
(collisions) over the last 5Gyr: Terzan3 - NGC 6553, Terzan 3 - NGC 6218,
Liller 1 - NGC 6522 and Djorg 2 - NGC 6553.
