Add Yahoo as a preferred source to see more of our stories on Google. The Andromeda galaxy helped Edwin Hubble settle a great debate in astronomy. Stocktrek Images via Getty Images A hundred years ago ...

For humans, the most important star in the universe is our Sun. The second-most important star is nestled inside the Andromeda galaxy. Don't go looking for it -- the flickering star is 2.2 million ...

Space Week is Oct. 4-10, so here are some of NASA’s latest discoveries and why Edwin Hubble’s history-making photo, taken on this day in 1923, revolutionized astronomy. This image above is from the ...

In a world where new things are found all the time and technology is always getting better, it's easy to think that science knows everything. Modern science has helped people understand things in ways ...

NASA’s Hubble Space Telescope has been trained on a single variable star that in 1923 altered the course of modern astronomy. V1 is a special class of pulsating star called a Cepheid variable that can ...

Hubble proved Andromeda is a separate galaxy by identifying a Cepheid variable star within it. Cepheid variables have a period-luminosity relationship: longer period means greater brightness. Knowing ...

Most people associate the discovery that faraway galaxies are receding from us — and thus, that the universe is expanding — with Edwin Hubble, thanks to his landmark 1929 paper. It was one of the most ...