Top Hubble Space Telescope images include the 1999 image of planetary nebula IC 418, the dust belt near the star Fomalhaut, Uranus and its rings, the galaxy Centaurus A and the 1998 photo of disks forming around stars. Additional pictures are the Tarantula Nebula, Horsehead Nebula and Arp 273.
The 1999 image of planetary nebula IC 418 gave scientists a glimpse of the complexity of the nebula, contrary to the round and featureless images of the former star scientists had before. Many scientists considered nebulae to be simple, but images like this one showed microstructures and irregular shapes among nebulae. As of 2015, scientists are still trying to figure out what created this nebula's structure.
The 2004 to 2006 images of the dust belt near the star Fomalhaut revealed an unexpected shape for the belt, and led to inquiries into its structure and creation. Photos of Uranus and its rings in the early 2000s aided scientists in studying ring changes from 2003 to 2007, and in the process astronomers also discovered two outer rings and two moons, called Mab and Cupid.
Photos of the galaxy Centaurus A in the 1990s furthered the study of black holes, and the 1998 photo of disks forming around stars increased knowledge of the formation of planets.