Simplify the following text for a Grade 6 native English-speaking person.
Original: It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard , et al . in 2003 , and was provisionally designated S\/2003 J 21 .
Simplified: It was found by a team of astronomers from the University of Hawaii led by Scott S. Sheppard , et al . in 2003 , and was designated S\/2003 J 21 .