Collisions Explosions Collesence

[flano]

Do collesences and explosions come under the title collisions or do the three come under some other catagory like impactions?
thank you
Maybe I should post this in Arts & Literature!

[ike_kozik]

coalescence is to grow; fuse

i'd say explosions are "A release of mechanical, chemical, or nuclear energy in a sudden and often violent manner with the generation of high temperature and usually with the release of gases."

they can't both come under the title "impactions"