The problem of light pollution -- and 5 ridiculously easy ways to fix it | Kelsey Johnson

90,901 views ・ 2020-01-06

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Translator: Ivana Korom Reviewer: Joanna Pietrulewicz
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Unless you've spent quality time on the International Space Station,
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this is probably not a view you are super familiar with.
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This is the east coast of the United States.
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That's New York down there in the lower right,
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and it's a band of light all the way up through Washington DC.
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Those cities are shining like jewels,
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highways are traced by webs of light.
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And all of that light is super photogenic.
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But there's a problem.
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That light is meant to be illuminating our sidewalks,
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and our streets and our houses.
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Instead, it's actually going up into the sky
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and out into the universe,
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where it's not doing any of us any good.
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When I see photos of this, of the Earth,
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I see environmental catastrophe.
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Those aren't jewels,
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those are tumors.
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I'm an astronomer,
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so it's really no surprise probably to anyone
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that I've always loved the night sky.
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I'm kind of a walking cliché.
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But when I was growing up in Minnesota,
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one of my favorite things to do on a summer evening
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was grab my old Raggedy Ann sleeping bag
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and take it out into a field behind my house,
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where I would spend hours looking at the night sky.
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And to do this, I had to brave not only the darkness,
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but also swarms of mosquitoes,
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and my sleeping bag really didn't smell very good.
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(Laughter)
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But there was one particular star
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that I would look for, night after night.
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And then I would play this game
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where I would try to focus on that star so intensely,
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that everything else would fade from my view
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and that single star would be all that I could see.
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I could only ever hold on to that focus
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for a few fleeting moments.
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But when I did,
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I felt this deep sense of connection to the universe.
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And almost a sense of vertigo,
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like I was going to fall into space.
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And when this happened --
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I know this sounds kind of ridiculous,
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but I would simultaneously feel unfathomably insignificant
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and also kind of weirdly important.
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That star I looked to night after night was called Vega.
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Vega is the brightest star in the constellation Lyra,
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which is not coincidentally the name of one of my dogs.
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(Laughter)
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But this experience is being lost.
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My favorite constellation, Lyra,
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this is what it would look like from Manhattan.
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For people who live in urban and suburban environments,
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if they go outside at night and look up,
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instead of being awestruck by the majesty of the universe,
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they see pretty much nothing.
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These unremarkable, completely blank night skies,
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of course are due to all of the light we produce at night.
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Those very same lights we see all the way from space
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are shining up into the atmosphere,
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where they bounce around and create this featureless smog of light.
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And that featureless smog of light has a name.
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It's called light pollution.
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As an astronomer,
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I can actually tell how bad light pollution is
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by the brightness of stars I can see in the sky.
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And it turns out
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that when you're trying to unlock the secrets of the cosmos,
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it's really helpful to be able to see the cosmos.
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And --
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[Laughs]
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Truth.
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And this light that we're trying to detect
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is coming from millions or billions of light-years away,
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and so it's generally pretty faint.
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And as an astronomer,
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I fight with this every day to do my job,
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and I have to tell you, it is a really big problem.
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But the problem is far worse
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than just losing some whimsical ability to gaze at the stars.
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For example,
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countless plant and animal species are affected.
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So we could talk about sea turtles
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or pollinators
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or any of these super important species
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that are also cute.
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Instead, I want to talk
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about these quietly unassuming dog whelks.
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You may have seen them around
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and not given them really a whole lot of thought.
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But they're pretty cool.
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So in an entire year
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a dog whelk will rarely move more than about 10 meters.
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That means that when they are attacking their prey
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they can hit this brisk pace of about a millimeter an hour.
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And --
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(Laughter)
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This works out OK,
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because they attack things like barnacles.
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(Laughter)
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So these dog whelks live in the intertidal area of coasts,
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where, it turns out,
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they're a pretty key part of the ecosystem.
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Not only are they one of the most dominant invertebrate predators,
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but other animals, like crabs and birds, think they're pretty tasty.
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So that leaves these poor snails in a kind of precarious situation,
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because if they go too low in the water,
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then crabs are a threat,
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but if they come out of the water too far,
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birds are going to have a feast.
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Why is an astronomer telling you about dog whelks?
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I ask that myself.
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Because their behavior is impacted by light pollution.
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For example,
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if dog whelks are subjected to artificial light at night
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they're about twice as likely to stay under the water with a predator.
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And that puts them at increased risk.
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And it's not like they can make a speedy escape.
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And so these --
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(Laughter)
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And the other issue is because they literally move
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at a snail's pace.
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If a population is wiped out,
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it can take decades to replenish.
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And that, in turn, affects the rest of their ecosystem
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and the other species, like the birds and the barnacles and the crabs.
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So this is just one small and slimy example
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of how light pollution can unleash a cascade effect
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on an entire ecosystem.
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Virtually every species that has been studied to date
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is impacted by light pollution.
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And that includes humans.
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So let's talk about us.
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You are probably not surprised to hear
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that light pollution can affect your ability to sleep well at night.
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But you might be surprised to hear that light pollution is linked to obesity.
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In fact, in a recent study
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they found that light pollution contributed to over 70 percent
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of the obesity rates in 80 countries.
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More than that,
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light pollution actually contributed about the same amount to excess weight
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as eating junk food.
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And it gets worse.
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For people who are subjected
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to significant amounts of artificial light at night
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they're about 50 percent more likely to get breast cancer.
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And in fact, light pollution is correlated with types of cancer
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across the board.
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And in controlled lab experiments
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there's a direct link between increased artificial light at night
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and a rate of tumor growth.
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You might be wondering how normal light
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could possibly impact cancer rates.
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It likely all comes down to the super important hormone
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called melatonin,
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which we have evolved over millions of years
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to produce on a day-night cycle, or a circadian rhythm.
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What happens is that when light impacts
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the retina at the back of our eye at night
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it can disrupt melatonin production,
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and when melatonin production is disrupted,
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a whole chain of other chemical processes are affected,
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and that includes estrogen production.
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And when we throw this chemical balance out of whack,
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really bad things can happen.
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In fact, things are so bad,
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that the International Agency for Cancer Research
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has said that disrupting the human circadian rhythm
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is a probable carcinogen.
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Also, for fun, I want to let you know
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that light pollution has been linked to,
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let's see -- headaches, anxiety, depression, diabetes,
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cardiovascular disease and the list goes on.
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But maybe you don't care about your health.
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We're all going to die anyway,
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you might as well die in a brightly lit room.
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(Laughter)
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The fact that you're laughing about death is kind of amazing.
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(Laughter)
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You might still care about money.
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The money that's spent on that wasted light,
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and I mean just the light that's going out into the universe,
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and not doing us any good,
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is three billion dollars a year.
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That's enough money to build, like,
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1,000 utility-grade windmills,
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or fund the entire DC public-school system for over two years,
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or -- this is my favorite, because I really want one
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but I can't afford one --
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buy 30,000 Tesla Model X SUVs.
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(Laughter)
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And that includes the electric car tax credit.
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And then there are the existential costs.
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I don't have any data
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on how losing touch with our place in the cosmos
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impacts us.
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But I believe
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that this probably impacts our humanity
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more than any of the other scary statistics I can share with you.
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And it's getting worse with time.
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The amount of light pollution is doubling roughly every 35 years.
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That means that within the next decade
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virtually the entire eastern half of the United States
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will be perpetually brighter than twilight.
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And there's another issue with light pollution.
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The problem is way worse than we can see with our own eyes.
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Our eyes have evolved to just detect this tiny range
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of the full spectrum of light.
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All of this other light that we can't see,
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this invisible light,
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also has a pollution problem.
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Mostly it's from modern technology,
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things like cell phones or car-to-car radar,
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or now apparently we need appliances that can talk to each other.
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All of this modern technology is putting out strong signals
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that can completely swamp
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this exceedingly faint light we're trying to detect
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from the rest of the universe outside Earth,
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which just for the record, is most of the universe.
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(Laughter)
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And then, there are satellites.
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Satellites are a problem at both visible and invisible wavelengths.
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A host of private companies have plans to deploy tens of thousands of satellites
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into Earth orbit,
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where they will not only outnumber,
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literally outnumber the visible stars in the sky,
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while also beaming invisible light back to Earth.
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So for astronomers like me,
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who use invisible light to study the universe,
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it's going to be like staring at the Sun
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and trying to see a birthday candle behind it.
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Alright, I want to be clear
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that there's nothing inherently wrong with any of this modern technology.
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With cell phones or satellites or car radar.
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I'm not sure about kitchen appliances.
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(Laughter)
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I haven't broken down
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and gotten an oven that talks to my cell phone yet.
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And I use lights at night like everybody else.
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But here's the thing.
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Some problems in the world,
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like we've heard about today and you'll hear more about,
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are overwhelming and they seem intractable.
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Visible light pollution is not one of these problems.
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This is actually stupidly simple, OK?
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So here are five super simple things you can do.
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Don't use lights brighter than you need to.
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Don't use lights when you don't need them.
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Those lights you're using,
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make sure they're shielded down,
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so they're not shining up into the sky.
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And let's talk about LED lights.
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If you have a choice, don't buy the blue ones.
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Look for words like "warm white."
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If you buy LEDs with words like "natural light" or "daylight,"
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that's like saying you hate space.
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(Laughter)
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And finally,
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you could advocate for this.
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Even in your local community,
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find out if there's a lighting code
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and whether it could be made more night-sky friendly.
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Or dare I say, you could even advocate at the federal level,
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by politely asking our federal officials,
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some of whom may be here,
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to please not auction off our view of the invisible universe
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to the highest bidder to pollute at will,
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which is actually what happens.
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Now, like a good professor,
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I have homework for you.
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If you have never seen a truly dark night sky,
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I want you to go out and experience one for yourself.
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Because if you don't,
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you don't know what you're missing,
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and you don't know what humanity is losing.
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Thank you.
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(Applause)
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