He really wants to tell the secret but he knows he cant but like a ticking time bomb eventually itll spill
Not appropriate; it's talking about a personal experience and cannot be researched; it's also almost entirely subjective.
When we say essential appositive, this is the phrase that is considered as an important part of the sentence that describes the noun and cannot be omitted for this will change the thought of the sentence. Based on the given sentence above, the essential appositive would be "Famed Astronomer". The answer would be the first option.