To our weak eyes, Andromeda looks like a blurred stain of light in the night sky. With decent binoculars, it’s nearly oval form perfects into view. The light we observe when peering up at Andromeda originates from the hundreds of billions of stars that create the Andromeda galaxy and its spiral arms. If each of those bright stars were to shine brighter, the image below is what it would look like to us on our home planet Earth—a stunning galactic spiral for all to see. The image above was made by Tom Buckley-Houston, who place over the Andromeda galaxy on a picture of the night sky with a moon for contrast. Astronomer Alan McConnachie of the National Research Council Herzberg in Canada, says “The GALEX image of Andromeda is in the ultraviolet, and the extent of this image is close to the size of the optical image of Andromeda that everyone is familiar with. The moon is about 0.5 degrees in diameter; the Andromeda galaxy, measured on its longest axis, is approximately 2-3 degrees long.”
Therefore, if probable for Andromeda to be brighter, it would appear nearly six times larger than our moon. But at 2.5 million light-years from us, the Andromeda galaxy is not as effortlessly seen as the crescent in our night sky. The full scope of Andromeda, according to McConnachie, is nearly 20 degrees across, or the comparable to more than 40 full bright moons!