silence can be both beautiful and terrifying -
how can that be?

let's consult BrainyQuote.com for a clue

silence is full of music
- Marcel Marceau

silence is the sleep that nourishes wisdom
- Francis Bacon

the deepest feeling always shows itself in silence
- Marianne Moore

silence is the mother of truth
- Benjamin Disraeli

how can silence be both beautiful and terrifying?

perhaps, as per the above quotes,
because truth can arise from silence -
and it is truth that is both beautiful and terrifying