This is an expression that marks a change in the story to show something different is about to happen. (See: [[rc://en/ta/man/translate/writing-newevent]])
Possible meanings are 1) heaven, where God lives or 2) the sky. The first meaning is preferable. Use that meaning if your language has a separate word for it.
Possible meanings are that 1) "Saul threw himself to the ground" or 2) "The light caused him to fall to the ground" or 3) "Saul fell to the ground the way one who fainted fell." Saul did not fall accidentally.
# why are you persecuting me?
This rhetorical question communicates a rebuke to Saul. In some languages a statement would be more natural (AT): "You are persecuting me!" or a command (AT): "Stop persecuting me!" (See: [[rc://en/ta/man/translate/figs-rquestion]])