I can see why "going" was used, but I can't explain it to someone else. Is there a rule? is there an explanation to as why sometimes I can replace the base form of the verb "to go" for "going"? Thanks in advance.
Sentence: Going out in the rain is not possible. We will get wet.
Going out is a noun, or going out in the rain is a noun phrase. It is not a verb.
"possibility of" something has to be followed by a noun or noun phrase.
possibility of rain
possibility of a market crash
possibility of going out. Going out is fun. Going out = NOUN, a GERUND NOUN
possibility of seeing you.
possibility of playing tennis
Seeing you would be so nice. seeing you is a noun phrase.
Playing tennis is fun. playing tennis is a noun phrase.
Often, learners forget about gerunds that act as nouns.
Finally, "possibility of" cannot be followed by a bare infinitive like go. That's the grammatical fact here.
I believe it might be because "going" is used for the future. Such as, "I'm going shopping tomorrow". I think "go" is now in the present. Such as, "Go get ready for school". So in this case they haven't gone out yet, they're still inside. Thus, you would use "going".
It also doesn't sound good, but you'll realise that with practice.