Learn French: Il est possible que cette éruption ait lieu aujourd'hui. - It is possible that this eruption will happen today.

The expression il est possible que expresses uncertainty or a lower chance of something happening, which triggers the subjunctive mood. This contrasts with il est probable que (it is probable that), which suggests a much higher likelihood and therefore takes the indicative.

The English translation says "will happen", so why doesn't French use a future tense here?

French does not have a future subjunctive tense. Because il est possible que forces us to use the subjunctive mood, we must use the present subjunctive (ait lieu) to talk about both present and future events. The context of aujourd'hui makes it clear we are talking about a future possibility.

Why is the verb avoir used to translate the word "happen"?

The sentence uses the fixed expression avoir lieu, which means "to take place" or "to happen." Here, the verb avoir is conjugated in the third-person singular subjunctive as ait to agree with cette éruption.

Could I use Il se peut que instead of Il est possible que in this sentence?