Week of October 19-24, 2025
Just how far can we see on a clear, dark night? If you're a regular reader of this column, you know that the stars overhead lie many trillions of miles away, but these make up only a tiny fraction of all those in our Milky Way galaxy.
Though our galaxy spans some 600,000 trillion miles (100,000 lightyears), our eyes can see only those stars within the nearest 1% of that diameter. But there is something in our autumn sky that is considerably more distant — far beyond the stars of our galaxy — and we can see it with the unaided eye if we know just where to look.
Astronomers call it M31 or NGC224; most of us simply know it as the Great Andromeda Galaxy. M31 is a spiral galaxy similar in some respects to our own Milky Way, and it lies so far from us that its light has taken 2.5 million years to reach us. In other words, the faint wisps of light that enter our eyes tonight left that distant galaxy long before humans walked the face of the Earth!
It appears as a faint smudge in the direction of the constellation Andromeda, but to see it, you'd better have a clear sky without the effects of nearby city light pollution or moonlight. In addition, you must allow your eyes at least 30 minutes to become adapted to the darkness by not looking into any bright light.
If you still can't see it, you may need to try another trick used nightly by astronomers. It's called averted vision. Because the human eye is unable to register dim light near its center, gazing directly at such a faint celestial object can render it completely invisible. Look slightly off to its side, however, and the object will seem to pop into view.
After dark this week, M31 appears in the northeast, and there are three ways to use familiar stars and star groupings to direct your gaze to the right place. Use the accompanying illustration to help you find your way.
One technique is to look midway up in the northeastern sky for five stars that outline the sideways "W" of the constellation Cassiopeia. Take the uppermost three stars and imagine them to be an arrowhead, and follow it eastward a short distance until you see a faint smudge.
Another way to find it is to locate the four stars of the Great Square of Pegasus, then follow a line from the square's southwesternmost corner to its northeasternmost corner and continue along that path about the same distance.
A third way is to begin at the star Mirach in Andromeda, and follow it upward just past the star Mu Andromedae.
Long thought to be a nebulous cloud within the Milky Way, it was only during the early years of the 20th century that astronomers discovered it to be a galaxy unto itself, with hundreds of billions of stars, and one of perhaps a trillion or more such galaxies in the universe.
And it's there for all to see on any clear dark night — if you know just where to look!
Visit Dennis Mammana at dennismammana.com. To read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.
The Andromeda Galaxy is 2.5 million lightyears away from Earth.
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