Dark matter and dark energy make up about 95% of the known universe, and physicists still lack a unifying theory of everything.

Evidence

10 unsolved mysteries in science (CBC Radio)

Categorization

• corroborated: 2 independent passages support this claim
• XREF: connects to: Life is full of unfathomable mysteries that elude understanding. — Crews, Harry, A childhood the biography of a place, 374