Everything is as it is, every moment of existence, Now!
The notion of 'possible' is for those who cannot see 'the future', which already is as it is, every moment.
A simple answer is that it is impossible to have a two-dimensional triangle with four sides. Definitionally impossible.
So, that one example is sufficient to refute the ignorant and vain saying that 'anything is possible'.
Another impossibility is for this, or any other moment, to ever be other than as it is, Now! and Now! and Now!!!
(It's up to you to understand the implications of this as regards the vain notions of 'free-will/choice'!)
'Being' is not a 'possibility', it is an actuality/knowledge.