Sources:

 

Collins, George W., II. "Black hole." The Gale Encyclopedia of Science, edited by K. Lee Lerner and Brenda Wilmoth Lerner, 5th ed., Gale, 2014. Gale In Context: Science, https://link.gale.com/apps/doc/CV2644030304/SCIC?u=cobb90289&sid=SCIC&xid=8579ccd3. Accessed 7 Feb. 2020. 

 

"Black Holes." Astronomy, Gale, 2019. Kids InfoBits Presents. Kids InfoBits, https://link.gale.com/apps/doc/JSPGIT858028135/ITKE?u=cobb90289&sid=ITKE&xid=c809f549. Accessed 7 Feb. 2020. 

 

“What Is a Black Hole?” Newsela, Nasa.gov, 16 Dec. 2016, newsela.com/read/lib-nasa-black-holes. 

 

“What Is a Black Hole?” Discovery Education, cobb.discoveryeducation.com/learn/player/8dd50ef0-474e-45ca-9e50-b7b6d326e04f .