When scientists show clear, provable, solid evidence that the world is round, the evidence they present is an example of something that would be described as incontrovertible.
- in·con′tro·vert′i·bil′i·ty in·con′tro·vert′i·ble·ness
(comparative more incontrovertible, superlative most incontrovertible)
terms etymologically related to "incontrovertible"
in- + controvertible