Book:Spangenburg, Ray, and Diane Moser. A Look at Comets. New York: F. Watts, 2003. Print. headline here
Asteroid-a large--grater than 0.6 miles (1 km)--leftover chunk of material.
Astronomy-the scientific study of the universe.
Mass-the amount of material a boy contains.
Crust-the outer solid surface layer of an object.
Gravity-a force of attraction between two objects.
The stars can be read as constitutions. Some comments happened in 60 years. Some scientists can be pay money to guess at when comets will happen.
this book made a connection with me it help me understand about comments and I like this book.