In 1920, astronomers Harlow Shapley and Heber Curtis held a Great Debate. Shapley argued that the spiral nebulae were small and in the Milky Way, while Curtis took a more radical position that they ...

Some were gaseous, star-forming regions, such as the Orion nebula, or M42 – the 42nd ... could be enormous stellar systems outside the Milky Way – but astronomers now just call these systems ...

In November the Milky Way arches high across the mid-evening sky from east to west. At its eastern end, winter constellations ...

Space is really really big. Planet Earth is located in one of the spiral arms of the Milky Way (called the Orion Arm) which lies about two-thirds of the way out from the center of the galaxy.