NOTE: This and the following web pages contain a database of short essays from the Astronomy and Astrophysics Encyclopedia, ed. Stephen P. Maran. They are updated weekly. This work is part of a new effort in parallel with NED (NASA/IPAC Extragalactic Database) and, among contributions from the authors listed below, makes use of NASA's Astrophysics Data System Abstract Service.

1. Antonucci, Robert. Active Galaxies and Quasistellar Objects, Blazers
2. Barnes, Joshua E. Galaxies, Disk, Evolution
3. Barrow, John D. Cosmology, Theories
4. Barthel, Peter. Active Galaxies and Quasistellar Objects, Interrelations of Various Types
5. Baum, William A. Galaxies, Elliptical
6. Bekenstein, Jacob D. Gravitational Theories
7. Bertschinger, Edmund. Dark Matter, Cosmological
8. Binggeli, Bruno. Virgo Cluster
9. Blandford, Roger D. Active Galaxies and Quasistellar Objects, Accretion
10. Boldt, Elihu. Background Radiation, X-Ray
11. Bothun, Gregory D. Protogalaxies
12. Boughn, Stephen P. Gravitational Radiation
13. Bowyer, Stuart Background Radiation, Ultraviolet
14. Brandenberger, Robert H. Cosmology, Inflationary Universe
15. Carlberg, Ray. Galaxies, Spiral, Nature of Spiral Arms
16. Carr, Bernard J. Cosmology, Population III
17. Clayton, Donald D. Cosmology, Cosmochronology
18. Cohen, Marshall H. Active Galaxies and Quasisitellar Objects, Superluminal Motion
19. Cudworth, Kyle M. Galatic Structure, Globular Clusters
20. Deguchi, Shuji. Masers, Interstellar and Circumstellar
21. Dressler, Alan. Galaxies, Properties in Relation to Environment
22. Eilek, Jean A. Active Galaxies and Quasistellar Objects, Jets
23. Elmegreen, Bruce G. and Elmegreen, Debra Meloy. Galaxies, Spiral, Structure
24. Elitzur, Moshe. Masers, Interstellar and Circumstellar, Theory
25. Evans, Lloyd T. Stars, Cepheid Variable
26. Fabbiano, Giuseppina. Galaxies, X-Ray Emission
27. Fairall, Anthony P. Superclusters, Observed Properties
28. Fichtel, Carl E. Background Radiation, Gamma Ray
29. Giovanelli, Riccardo. Clusters of Galaxies, Radio Observations