If you turn on your TV, you will soon realize on the news that everything is out to get us. Astronomy is no different. Solar flares, asteroids, comets, you name it. All scary things that are actually quite real, and reason 512b that our space program should be taken seriously. But…those issues I just listed are really pretty small. One has to imagine that in a galaxy like the Milky Way, with an estimated 400-600 billion stars and likely millions of worlds that exist near them, horrible and catastrophic things are constantly occurring. Worlds are colliding, the skies in some cases, are literally falling, suns are exploding, and beings that we may never meet, are having days far worse than any of us can hardly imagine.
But that’s part of the beauty, in a strange way, of looking up. We are small. Very small. Not just in a sense of our size, but in a sense of our significance. Our issues, our problems, our flaws, our fears. The dent in your car, your phone’s reception, the brand of boots your dog wears. All very, very…small.
So small that sometimes a photograph when thought of relative to distance helps us relate to the tiny specs we are, and the enormity of space. Above is a picture from our backyard at the farm of the northeast sky last weekend, around midnight. Below is the same, at a slightly higher magnification. The white smudge you see, is actually an entire galaxy, M31, or sometimes referred to as the Andromeda Galaxy. It’s a very close representation to what our own galaxy looks like, at a distance of 2.5 million light years away. A light year being the distance light can travel in a year. Light as we perceive it, is instant. But much like seeing the delay in the sound of someone beating a drum at a concert from the last row in the house, light takes time to get to us too.
While sound moves at a pokey 770 miles per hour, light moves at about 186,000 miles…per second. So, light traveling 186,000 miles each and every second, of each and every day, still takes 2.5 million years, just to get here from our nearest spiral galaxy neighbor, M31. Miles don’t really do it justice. What’s even better, we’re seeing the light as it was when it left M31…2.5 million years ago. We are essentially looking into the past. That light was created when the ice ages were first occurring here on earth. Forget telescopes, humans as we know them weren’t even here yet, a guy named homo habilis was roaming around. If we could peak in on ‘real time’ in M31, it would be a world advanced 2.5 million years. Who knows what’s changed since then! Heck it might not even be there anymore, gobbled up by some galactic monster. (Okay, maybe unlikely.)
But M31 is also 220,000 light years, across. If we could see the faint portions that our light pollution covers up, we would see that M31 takes up six times more real estate in the night sky than a full moon, that’s pretty big! All we can see here on Earth however is usually the bright center part, which is a faint smudge on a clear night, about as much as your thumb would cover if held at arm’s length. All told, in the faint parts we can barely see, and smudge that we can, lies one trillion stars, according to a recent survey from the Spitzer Space Telescope. One trillion possible Suns, with the possibilities of their own solar systems, worlds, life forms, beings, consciousnesses, and someone else’s problems. Just in that little, insignificant smudge.
The future of our two galaxies is even more interesting. My Great Aunt Mary will tell you she’s lived to be 94, and never thought she would see this many years. If she could just share the secret to long life with the rest of us and if we could all stretch it out a bit (maybe 4 billion years) more we would see a real treat. M31 and our Milky Way are on a collision course for one another. Despite what you’re picturing in your heads of massive explosions and CNN-style breaking news stories, it will be a rather slow process. The odds of two stars, or anything for that matter colliding, is rather slim. Think of it more like two swarms of bees colliding. Certainly some bees will smack into one another, but not many. It is said that in our galaxy, two stars are about like two houseflies, about 250 miles apart. Space is just ridiculously big.
This is not to say it will be a good time to be here on your 4 billionth birthday. Gravity usually wins, and with each little tug or twist of the gravity from other objects that we will pass by in M31, stars, planets, moons, and everything else in our galaxy will be flung far and wide across the Milky Way, wreaking havoc on whoever is still here. Each object has its own gravity, that’s why we stay near our sun in a pretty steady orbit. If you bring in bigger stars, or more stars that also have their own gravity, well… it’s sort of like driving a girl you just met to a party in your ‘94 Taurus, and every guy there drives a Benz. She’s going to get pulled away.
But fear not! This hobby of ours is not all doom and gloom. Remember it’s a thing of beauty. Looking up is your own little moment of reflection, and a time to consider that just as the stones beneath your feet have been on this earth since it’s beginning to be in that very location as the solid ground you stand on, the stars and galaxies above your head have been through an even greater journey, and shine with a brightness from trillions of miles away, allowing us to literally look into the past, and wonder what is, what was, and what will be on these worlds so very far away.
In the end, this here is a picture of a smudge. Just a smudge to us. To someone that calls it home, it’s an island universe over 200,000 light years wide, filled with one trillion stars. In this smudge, one has to assume that entire wonderful civilizations have risen, and fallen, wars have been waged, some won, some lost, amazing works of ingenuity have been created, and beings beyond our imagination exist, with emotional and spiritual connections to one another that may transcend the bonds of this universe. What’s better – someone in M31 could be saying the same thing right now while looking back…at us. We…are small.