The Andromeda Galaxy May Not Be As Big As We Thought

The 2011 Brit Marling sci-fi film Another Earth posited the idea of a mirrored version of Earth entering the Milky Way. The idea seems preposterous, and it probably is–in the film, the “other Earth” is more of an alternate reality, inhabited by our own human copies–but recent findings about our closest galactic neighbor, Andromeda, make the premise just a bit more plausible.

Though there are no known Earth copies in Andromeda, new research published in Monthly Notices of the Royal Astronomical Society (via  Gizmodo) finds the galaxy is more like the Milky Way than we previously thought. Originally believed to be as much as two times the size of our home galaxy, the new study details Andromeda is actually roughly the same size as the Milky Way. That means that instead of being second-in-command of the Local Group, a collection of our 54 closest neighboring galaxies , we’re now twin rulers with Andromeda.

M31: The Andromeda Galaxy What is the nearest major galaxy to our own Milky Way Galaxy? Andromeda. In fact, our Galaxy is thought to look much like Andromeda. Together these two galaxies dominate the Local Group of galaxies. The diffuse light from Andromeda is caused by the hundreds of billions of stars that compose it. The several distinct stars that surround Andromeda’s image are actually stars in our Galaxy that are well in front of the background object. Andromeda is frequently referred to as M31 since it is the 31st object on Messier’s list of diffuse sky objects. M31 is so distant it takes about two million years for light to reach us from there. Although visible without aid, the above image of M31 is a digital mosaic of 20 frames taken with a small telescope. Much about M31 remains unknown, including exactly how long it will before it collides with our home galaxy. Image Credit & Copyright: Robert Gendler. This great astrophotographer and scientist is still not with us here on Instagram. But, you can find take a look at all of his amazing astrophotos on his website 👉

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This new information completely alters the expected future of our two galaxies. Though astronomers have known for a long time that the Milky Way and Andromeda will eventually merge (not for like five billion years, don’t worry), the results of the collision have new connotations. Instead of Andromeda absorbing the Milky Way, it’s now believed the merger will create a giant new galaxy, the king of the Local Group. It’s not really known what, exactly, will happen to the planets and our Sun in this instance, but five billion years is a long way out. It’s likely our Sun will survive the merger, and that the giant black holes in both galaxies will combine.

For now, the most exciting part about the new findings are that they allow us to learn more about the formation and history of the Andromeda galaxy, as well as its future role in the evolution of the Local Group. Only time will tell if it contains a second Brit Marling.

Image: Wikimedia Commons

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