Complex sentence: Tyche is the nickname given to a hypothesized gas giant planet located in the Solar System's Oort cloud, first proposed in 1999 by astronomer John Matese of the University of Louisiana at Lafayette.
Split into simpler sentences: Tyche is the nickname given to a hypothesized gas giant planet located in the Solar System's Oort cloud. Its existence was proposed in 1999 by astronomer John Matese of the University of Louisiana at Lafayette.