Mastodon Feed: Post

Reblogged by jsonstein@masto.deoan.org ("Jeff Sonstein"):

coreyspowell ("Corey S Powell") wrote:

Remembering another notable date in history: 100 years ago this month, Edwin Hubble proved that our galaxy is just one small island in a vast cosmic sea.

Our awareness of galaxies is just one century old! I dig into the full story in my latest Invisible Universe column:

https://invisibleuniverse.substack.com/p/the-100th-birthday-of-the-universe #space #science #astronomy #history

Attachments:

• Edwin Hubble’s glass photographic plate H335H, obtained with the 100-inch Hooker Telescope Oct. 5/6, 1923, shows the galaxy M31. Three “new” stars are marked in black with the letter N. However, Hubble later noted that the star at the top right was present on earlier plates but fluctuated in brightness. He subsequently crossed out the N and marked it with “VAR!” in red. This is the Cepheid variable M31-V1, which Hubble used to calculate the distance to M31 and solve the mystery of the spiral nebulae.