One last key concept in Special Relativity is introduced before discussion turns again to black celestial bodies (black holes in particular) that manifest the relativistic effects students have learned about in the previous lectures. The new concept deals with describing events in a coordinate system of space and time. A mathematical explanation is given for how space and time reverse inside the Schwarzschild radius through sign changes in the metric. Evidence for General Relativity is offered from astronomical objects. The predicted presence and subsequent discovery of Neptune as proof of General Relativity are discussed, and stellar mass black holes are introduced.

Reading assignment:

Sheehan, William and Richard Baum. "Neptune's Discovery." Astronomy (September 1996) : 43-49. Fernie, J. Donald. "In Pursuit of Vulcan." American Scientist (82) : 412-415.

Resources

Class Notes - Lecture 12 [PDF]

Step by Step into a Black Hole

Courtesy of Ute Kraus, Max-Planck-Institut für Gravitationsphysik, ;Golm,

and Theoretische Astrophysik, Universität Tübingen

http://www.spacetimetravel.org/expeditionsl/expeditionsl.html

Black Holes and Neutron Stars

"Written Description of Visible Distortion Effects"

Courtesy of Robert Nemiroff, Michigan Technological University

http://antwrp.gsfc.nasa.gov/htmltest/rjn_bht.html