Complex sentence: Robert C. Kennicutt, Jr. is an American astronomer, Plumian Professor of Astronomy at the University of Cambridge, and Editor-in-Chief of the Astrophysical Journal.
Split into simpler sentences: Robert C. Kennicutt, Jr. is an American astronomer. He is the Plumian Professor of Astronomy at the University of Cambridge and Editor-in-Chief of the Astrophysical Journal.