A July 23, 2003 article in The Telegraph touches on the scope of what we see through telescopes in a clear, dark night sky:
There are 10 times more stars in the night sky than grains of sand in the world’s deserts and beaches, scientists say. Astronomers have worked out that there are 70 thousand million million million – or seven followed by 22 zeros – stars visible from the Earth through telescopes. The total is said to be the most accurate estimate yet of the number of stars.
The scale of our own Milky Way galaxy is incomprehensible to me. And consider that all the stars we can see with our naked eyes are in our own galaxy. The only other galaxy we can see from the northern hemisphere is the Andromeda galaxy. We don’t see the individual stars in Andromeda, just its faint light, a tiny glow in the darkest night sky. The Milky Way is home to around 400 billion stars and is 120,000 light years across. I can relay those numbers but I cannot truly understand them; they are too enormous for my tiny little brain to comprehend.
The scale of the known universe is beyond me. There’s a reason we bandy about the term “astronomical.” For me, the term means vastness with no limits; an exponent of “huge” so large it cannot be expressed with even the most advanced mathematics and physics and metaphysics.
Scale. How can we possibly believe, in a universe so incomprehensibly large, that the tiny speck upon which we live matters beyond the immediate? Our time and our impact on the physical universe is so small it is impossible to understate. Hell, we could somehow figure out how to blow up our own Moon and the universe wouldn’t even shudder.
Carl Sagan and many of his contemporaries, as well as those who have followed in his footsteps, grasped the magnitude our humankind’s stupidity, I think. They realize that, in all the vastness of space and time, the tiny dot we call Earth is the only home we have ever known and the only one we will ever know. An acknowledgement of that simple understanding should become the mantra that begins our day every day. If we were to start every day with an acknowledgement of just how unimportant we are, we might not make so many blunders under the mistaken impression that what we do ultimately matters. We would, instead, begin each day expressing wonder at this enormous universe which we cannot begin to understand.