31.   The collisions create dense dust clouds that trigger star formations, but the clouds are so opaque that the Hubble Space Telescope is blind to them.

32.   The discovery means scientists might have to rethink their theories of star formation, said Harvard astronomer Paul Ho, another member of the team.

33.   Wang said the Milky Way center is in a constant roar of star formation and destruction.

34.   The discovery advances theories on star formations.