Body: "Astrophysics" is the branch of astronomy that employs the principles of physics and chemistry together to describe space.
Several topics in "Astrophysics" include Theoretical astrophysics, Observational astrophysics, Radio astronomy.
to ascertain the nature of the astronomical objects, rather than their positions or motions in space is some of the cause to investigate "Astrophysics".
Carl Sagan, Neil DeGrasse Tyson, Stephen Hawking are some authorities of "Astrophysics".