Includes bibliographical references and index.

Top secret : for your eyes only! -- Black holes : the basics -- Types of black holes -- Fact file : discovering black holes -- How to see a black hole -- Blazars and quasars -- Danger on the event horizon -- Spaghettification -- An impossible picture -- Wormholes -- Black hole crash -- Fact file : Cygnus X-1 -- Penrose energy.

"Welcome, Agent 359. This file is full of top-secret information about black holes. Learn the basics of how black holes form, their different sizes, and how they were found. Then, discover what scientists are learning about them now. What will you do with our new knowledge? Good luck and remember these are top secret space files!"--

Ages 8-11 Bearport Publishing Company

Grades 4-6 Bearport Publishing Company