Today, in the history of astronomy, Edwin Hubble’s identification of coffees in the M31 of Hubble appears on a large scale of the universe.
NASA released this Hubble Space Telescope Panorama of our nearest cosmic neighbor Andromeda Galaxy in January 2025. It took 10 years and 600 shots to make it. Credit: NASA, ESA, Benjamin F. Williams (Uvashington), Zuo Chain (Uvashington), L. Cliftton Johnson (Northwestern); Image Processing: Joseph Depasquel (STSCI)
On October 4, 1923, Edwin Hubble took a photographic plate of Andromeda Nebula (as it was known) using a 100 -inch hooker telescope at Mount Wilson. The next night, October 5, he took another plate and found that a star that belonged to Nebula had turned into brightness. First, he thought that it is a Nova, a type of stellar explosion. But finally, he realized that it was a special type of variable star – and it means that he could measure the distance of this star correctly.
By studying these variable stars – called safids – in our own galaxies, astronomers already knew that when they were diverse, they were related to their inner brightness. Henrita Levitt, an astronomer at Harvard College Observatory, worked in 1912 that long -term safids take to pulsate, they are bright (and possibly large). So knowing the true glow of the star and comparing it, how faintly appeared, Hubble can calculate how far the star was.
Their answer: 1 million light-year. Today, we know that Andromeda Galaxy (M31) is actually about 2.5 million light-year away, but the implications of the measurement of Hubble stand. What they found changed our concept of the universe forever and confirmed that Andromeda and its nebulus breathrain were actually different from the Milky Way throughout the galaxies – their own island universe.
