This TED Talk features astronomer Kelsey Johnson, recorded live at TED at NAS 2019.

Unless you've spent quality time on the International Space Station, this is probably not a view you are super familiar with.

This is the East Coast of the United States. That's New York down there in

the lower right, and it's a band of light all the way up through Washington, D.C. Those cities are

shining like jewels. Highways are traced by webs of light, and all of that light is super photogenic.

But there's a problem.

That light is meant to be illuminating our sidewalks and our streets and our houses.

Instead, it's actually going up into the sky and out into the universe,

where it's not doing any of us any good.

When I see photos of this, of the Earth, I see environmental catastrophe.

Those aren't jewels. Those are tumors. I'm an astronomer, so it's really no surprise

probably to anyone that I've always loved the night sky. I'm kind of a walking

cliche. But when I was growing up in Minnesota, one of my favorite things to do on a summer

evening was grab my old raggedy-on sleeping bag and take it out into a field behind my house

where I would spend hours looking at the

night sky. And to do this, I had to brave not only the darkness, but also swarms of mosquitoes,

and my sleeping bag really didn't smell very good. But there was one particular star that I would look for a night after night,

and then I would play this game,

where I would try to focus on that star so intensely

that everything else would fade from my view,

and that single star would be all that I could see.

I could only ever hold on to that focus for a few fleeting moments. But when I did,

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