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 ...

Giant deep space alien spiral galaxy concept. Loop of high angle revolving galactic stellar milky way supercluster created without third-party elements depicting celestial eternity of the universe.

Giant deep space alien spiral galaxy concept. Loop of high angle revolving galactic stellar milky way supercluster created without third-party elements depicting celestial eternity of the universe.

It is clear that human beings, throughout history, have always had a constant curiosity to discover everything that happens ...

In the 1920s, astronomers thought that the Milky Way was the entire universe. Hubble's discovery revealed a much bigger ...

Hubble’s work pushed the field of astronomy forward, starting with his paper demonstrating that some objects exist outside ...

The elliptical galaxy NGC 4660 is one of a hundred galaxies imaged by Hubble that are members of the nearest large galaxy cluster to Earth, the Virgo Cluster. NASA’s James Webb Space Telescope has ...

Centaurus A: NGC 5128 is a galaxy in constellation Centaurus, discovered in 1826 by Scottish astronomer James Dunlop. Messier ...

Island universes referred to the idea that there could be enormous stellar systems outside the Milky Way—but astronomers now just call these systems galaxies. In 1920, astronomers Harlow Shapley and ...

Somewhere in between, humans realized the universe is much larger than our Milky Way — that the spiral nebulas visible through telescopes were, in fact, other galaxies in their own right.

In 1952, astronomers began the first major radio survey of the Milky Way. Astronomers theorized that the galaxy had a spiral structure, and finally, they detected the spiral arms, revealing the Milky ...