In ancient Greece, Aristarchus, recognizing the enormous size of the Sun compared to the Earth, concluded that the Sun was the center of the solar system.
In ancient Greece, Aristarchus, recognizing the enormous size of the Sun compared to the Earth, concluded the Sun to be the center of the solar system.
In ancient Greece, Aristarchus, recognizing the enormous size of the Sun compared to the Earth, concluded that the Sun was the center of the solar system.
In ancient Greece, Aristarchus, recognizing the enormous size of the Sun compared to the Earth, concluded the Sun to be the center of the solar system.
The verb "conclude" idiomatically takes a "that"-clause, never an infinitive.