JAN. 7, 2017 / JORDAN VINSON
Did you know you can see another galaxy with the naked eye from the Marshall Islands during this time of the year? It’s the Andromeda Galaxy, aka M31. At 2. 5 million light years away it’s the most distant object visible to the unaided eye, especially during times of little or no moonlight.
It lives in the constellation Andromeda, which sits high in the night sky at 8 p.m. this time of year. Look directly north (or more toward the west if it’s a later time during the night) for the easy-to-spot constellation Cassiopeia, which looks like a semi-flattened “m.” You can’t miss Cassiopeia. Look further “upward” above Cassiopeia, and you’ll find Andromeda. Its principal structure consists (mostly) of one long arc of five bright stars (and some dimmer ones) stretching east to west overtop Cassiopeia. The length of the constellation is about double that of Cassiopeia. At this time of night, it connects into the bottom right of a large square-shaped constellation called Pegasus.
Now that Andromeda’s arching line of stars is located, look back down to Cassiopeia. The left “ ” of Cassiopeia forms a triangle that points almost directly up to one of those bright stars in the arch of Andromeda. That’s Mirach. The Andromeda Galaxy is located “down and to the left” a few degrees from Mirach. You can actually follow a trail of two stars shooting downward and leftward from Mirach, taking you directly to M31.
It’s not going to look like much to the naked eye, but if you avert your eyes away from the galaxy’s location you’ll be able to use your eye’s more sensitive rod cells to suck up more light than by looking directly at the target. You should see a small smudge of light.
It’s highly recommended you bring out a pair of binoculars. With even bargain optics, M31 will look much more impressive, with a more defined, light emitting core and a considerably long halo. That halo comprises the arms of the spiral structure surrounding it. Binoculars bonus: Scoot your binoculars a little further “downward” from M31, and you’ll see an even smaller smudge of light. That’s M32, a dwarf elliptical satellite galaxy orbiting M31. It’s nothing compared to the Andromeda Galaxy, with a length of approximately 220,000 light years and one trillion stars—or roughly double the size and mass of the Milky Way.
Fun fact: M31 is coming right for us. Astronomers predict the Andromeda Galaxy will slam into the Milky Way in about 4.5 billion years, forever changing the structures of each galaxy.