Comet Encke was "discovered" in 1786, 1795,1805, and 1818 by different astronomers. These comets were found to be the same only after orbital calculations in 1819 by the German astronomer Johann Encke, who then predicted its return in 1822.

A new look at how light bends as it travels through the universe could point to an alternative theory of gravity

Retrograde motion is an effect of changing perspective. Inferior planets Mercury and Venus show retrograde motion on either side of inferior conjunction. They "overtake" Earth as they pass between Earth and the Sun.

Supermassive black hole winds blowing at 36 million mph can sculpt entire galaxies

First discovered in 1826, the Bug Nebula is one of the brightest planetary nebulae. The central star is thought to have an extremely high temperature, and its intense heat lights up the surrounding stellar material.

Some scientists speculate that the universe is shaped like a doughnut, instead of stretching to infinity. It’s a topology that could eventually be mapped.

RCW 49 is one of the most productive regions of star formation to have been found in the Milky Way. It spans a distance of about 350 light-years, and it is thought that over 2200 stars reside within it.

New discoveries from the far reaches of space

Camelopardalis is a dim constellation of the far northern sky, representing a giraffe. The giraffe's long neck can be visualized as stretching around the north celestial pole toward Ursa Minor and Draco.