It’s 100 years since we learned the Milky Way is not the only galaxy

Edwin Hubble's work showed that Andromeda (pictured) was a separate galaxy outside the Milky Way. Nasa/JPL-Caltech

On Sunday November 23 1924, 100 years ago this month, readers perusing page six of the New York Times would have found an intriguing article, amid several large adverts for fur coats. The headline read: Finds Spiral Nebulae are Stellar Systems: “Dr Hubbell Confirms View That They Are ‘Island Universes’; Similar to Our Own”.

The American astronomer at the centre of the article, Dr Edwin Powell Hubble, was probably bemused by the misspelling of his name. But the story detailed a groundbreaking discovery: Hubble had found that two spiral-shaped nebulae, objects made up of gas and stars, which were previously thought to reside within our Milky Way galaxy, were located outside it.