The Expansion of the Universe: From the Hubble Law to the Hubble Space Telescope, and Beyond(!)

About Hubble’s Law

Hubble’s Law shows our Universe to be ever-changing, expanding its limits in space and time simultaneously.  These findings were revolutionary in the 1920s. Read on to learn why. 

What did Hubble do, and how did he find his Law?

In 1929, the American Astronomer Edwin Hubble made a simple graph showing that galaxies farther from each other move away from each other systematically faster.  He drew a simple straight line on the velocity vs. distance plot shown here,  summarizing the trend that now bears his name as “Hubble’s Law.”  The law, represented today as: 

Velocity= (Hubble’s Constant) x Distance

implies that the Universe is expanding, and Hubble’s Constant measures how fast.  

How do Hubble’s galaxies look through the Hubble Space Telescope? 

In this interactive version of Hubble’s graph, based on his original published figure, yellow circles mark individual galaxies, and green labels show identifiying NGC numbers (or names) for each galaxy.

Click on a yellow circle to learn more about each galaxy and see a Hubble Space Telescope image of it superimposed on all-sky images. [clicking online graph goes to https://www.thinglink.com/card/1295138622952964097 ]