Conclusion

In the physics of neutron stars and black holes, we clearly see the central role of general relativity in modern astrophysics. Relativistic physics is necessary to fully understand the most energetic phenomena in the universe - from supernova explosions of stars to the driving force that makes some active galactic nuclei the brightest objects in the universe.

Elementary Einstein now turns to general relativity as a way to describe the universe as a whole:

Chapter 5: Cosmology

If you'd like to continue your exploration of black holes and their kin, you might want to jump to the category Black holes & Co. of our Spotlights on relativity.