Complex sentence: Strömgren was born in Helsingborg in Scania received his doctorate at Lund University in 1898, becoming docent there the same year, worked at the University of Kiel from 1901 and became Professor of Astronomy and director of the observatory of the University of Copenhagen in 1907.
Split into simpler sentences: Strömgren was born in Helsingborg in Scania, received his doctorate at Lund University in 1898, becoming docent there the same year. He worked at the University of Kiel from 1901 and became Professor of Astronomy and director of the observatory of the University of Copenhagen in 1907.