The sky is inherently democratic.
It's accessible, in principle, anyway, by anyone, everywhere, just simply by the act of looking up.
But like so many beautiful things around us, it's slipping away from us,
and we haven't even noticed, because we're honestly not really looking.
So what do we look at instead? Well, we look at our phones, we look at our computers, we look at screens of all kinds.
And honestly, we rarely even take the trouble to look up enough to see each other,
let alone taking that next step to looking up at the actual sky.
Now, there's a tendency to think that the loss of our dark night skies is the inevitable outcome of progress, change, technology.
And you know, that's just simply not true. Later on, I'll tell you why.
But first, I want to tell you about my experience of the dark night sky.
I never saw a truly dark night sky until I was 15. I was here, in Arizona.
I was on a road trip; I pulled over somewhere. I have no idea where I was, except I know what state.
And I looked up, and the sky was just filled with an impossible number of stars.
You see, I'm from New York City, and in New York, you can see the moon, you can see a couple of stars.
More often than not, they turn out to be airplanes when they land.
But there's really not much else.
As a result, most of my colleagues who are astronomers spent at least part of their youth looking up at the sky in their backyard.
I never really had that experience, and, as a result, I'm really disappointing on camping trips.
I don't really know many constellations.
The ones I do know, you probably know them, too.
But I'll never forget that experience of the first time I saw the dark night sky.
And I was just flabbergasted at how many stars there were. And I felt tiny.
Then I also felt like, "Where's this been hiding this whole time? Who's been hiding this sky from me?"
Of course, the answer is obvious if you think about it or if you look at the picture on the left,
where you're seeing the same neighborhood taken during a blackout versus on an ordinary night.
You can't see the stars if you drown them out with light.
Take a look at our planet. This is our planet from space.
Unlike stars, which are hot and glow invisible light so we can see them,
our planet is, astronomically speaking, pretty cold. So it doesn't really glow.
When you see the planet looking like a blue-green marble the way it does in this picture,
you're seeing it because the sunlight is reflecting off of it,
and that's why you can see the oceans, the clouds, the land.
So if the sun wasn't shining on it, we wouldn't be able to see the earth, right? Or would we?
This is our earth at night, and it is one of the most striking examples of how we have affected our planet on a global scale.