Simplify the following text for a Grade 8 native English-speaking person.
Original: Its closest approach to Jupiter was on March 5 , 1979 , at a distance of about 349,000 kilometres ( 217,000 miles ) from the planet 's center .
Simplified: Its closest approach to Jupiter was on March 5 , 1979 , at a distance of 349,000 kilometers ( 217,000 miles ) from its center .