How would you like to see the farthest thing visible to the naked eye?
It’s possible to see the Andromeda Galaxy, the next-door neighbor to our Milky Way Galaxy, but you’ll need to bundle up, sit back on a lawn chair and a dark sky — like the kind you find out in the countryside. If you’re on a mission to spot Andromeda in areas compromised by light pollution, you’ll need a pair of binoculars or small telescope.
If you received a new scope for Christmas, now’s your chance to really go deep! Just make sure you let your new telescope and all the eyepieces sit outside for a good 30 to 45 minutes so the glass and/or mirrors can acclimate to colder temperatures. If you don’t, you will get some really blurry and funky views.
Once you settle into your lawn chair, give your eyes 15 to 20 minutes to adjust to the darkness. If you’re using any kind of star map, read it with a headband flashlight that has a red lens so you don’t ruin your night vision. These can be found at hardware stores or anywhere that sells camping gear. You can also fire up a stargazing app on your phone or small tablet. My favorite is called “Sky Guide.”
The best way to find the Andromeda Galaxy is to locate the constellation Andromeda the Princess, which is attached to the constellation Pegasus the Winged Horse in the early-evening western sky. Follow the left arm of the constellation Andromeda. Near the halfway point of that arc of stars is the moderately bright star Mirach. To the right of Mirach, you’ll see two much fainter stars. To the immediate lower right of those two stars, look for a very small, faint, patchy cloud. That’s it, the Andromeda Galaxy. Again, you might need binoculars or a small telescope to find it.
You might not be blown away when you first spot it. All you’ll see is a ghostly patch of light and a bright nucleus. Even with large telescopes I bring to stargazing parties, you usually don’t see too much more than that, although the galaxy will have a little more shape and definition. Astronomical photographs reveal more detail because they can gather and accumulate more light than our human eyes.
Nonetheless, that little ghostly patch of light is made up of the collective light of possibly a trillion stars at a distance of 2.5 million light-years away (one light-year equals nearly 6 trillion miles). Since a light-year is defined as the distance light travels in a year’s time, the light that you’re seeing from Andromeda has been traveling to your eyes for 2.5 million years. We don’t see the light as it is now, but as what it looked like 2.5 million years ago. From what astronomers know about galaxy lifetimes, it hasn’t change all that much in appearance, even over a couple of million years.
Despite that incredible distance, Andromeda and the Milky Way are the closest neighbors to each other, but without a doubt, Andromeda is the larger galaxy, possibly twice the diameter of our Milky Way. Like our home galaxy, most of the mass that makes up Andromeda is invisible, what astronomers call dark matter, which still remains a mystery.
The Andromeda Galaxy is very important to the history of astronomical discovery. Less than a hundred years ago, the Milky Way was all we thought there was to the universe. What we now know as the Andromeda Galaxy was then thought to be just a big cloud of nebulosity. That all changed in the 1920s when Edwin Hubble and his assistant Henrietta Leavitt discovered that the Andromeda Galaxy was a heck of a lot farther away than previously believed. They used what is known as Cepheid variable stars to gauge how far away Andromeda was. Cepheid variable stars vary in size and brightness over a period related to average brightness. They’re what astronomers call “standard candles.”
As it turned out, through painstaking observation and photographic analysis, Cepheid variable stars were found in the Andromeda nebula. By observing their brightening and dimming cycle, it was determined that the Andromeda nebulae was way, way farther away than anyone ever thought. Furthermore, it was concluded that it was independent of our Milky Way. Hubble gets all the credit for this discovery, but Leavitt actually discovered the Cepheid variables in Andromeda and did most of the labor-intensive legwork.
One more thing about Andromeda: It and the Milky Way are on a collision course. They’re approaching each other at an estimated 60 to 80 miles a second! Don’t worry, though, because even at that speed the two galaxies won’t crash into each other anytime soon. Give it a little more than 4 billion years.
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A dinner and a program from 5:30-8:30 p.m. Saturday, Jan. 12, at Springbrook Nature Center in Fridley. For more information, call 763-572-3588 or go to springbrooknaturecenter.org/361/Springbrook-Nature-Center.
