All Episodes

January 28, 2010 17 mins

Most city dwellers are familiar with contaminated water and smoggy air -- but have you heard of light pollution? Listen in as Allison and Robert explore the effects of light pollution -- and whether humans are better off in the dark.

Learn more about your ad-choices at https://www.iheartpodcastnetwork.com

See omnystudio.com/listener for privacy information.

Mark as Played
Transcript

Episode Transcript

Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:01):
Welcome to Stuff from the Science Lab from how stuff
works dot com. Hey, this is Alison Madam like the
science editor at how stuff works dot com. And this
is Robert Lamb, science rider how stuff works dot com.
Thanks for joining us today. We're talking about late pollution, yes,

(00:26):
which is not that does not mean mild pollution, diet
pollution if we're talking in terms of illumination right physically,
we're talking about artificial light shining at night. Essentially, we're
shining at the wrong time of day, and night is
the wrong time of day. Correct, chew on that one. Listeners. Basically,

(00:46):
we live in a world divided into night and day.
Sometimes it's not exactly a fifty fifty split, depending on
where you happen to live, but still it's a natural
order of things. And when you start filling the uh
the nighttime with lights, electric lights and and Christmas lights
and and and all this, you're screwing it up. And

(01:06):
that's what we're talking about. The day is all the
ways you can can basically screw up the world around
you by lighting it up. Who knew? So what do
you see when you look at the night sky? I
guess it kind of depends on where you live. Yeah,
we both live in the Atlanta area. Of course, the
Atlanta area is not renowned for being an excellent stargazing place. Right,

(01:26):
there's no Midtown Observatory because when I look into the sky,
I tend to see either, um, like a seven forty
seven going over. I see a lot of those too, Yeah,
quite a few. Yeah, I think that's about all we see. Yeah,
So light pollution is it gets pretty bad, as you
can imagine in urban areas. Actually, one thing I found
was that you can tell how light pollution affects your

(01:48):
area by counting the stars and Orion and alright is
my favorite constellation anyway, because it's so easy to pick out,
which what what is it shaped light? Well, it's got
the four corners and then it has the diagonal belt.
When you see it in the the book, like what
does it look like a man like strangling a goat
or something like? They all would look like something tremendously elaborate.
And it's always like a square. Yeah, I mean it

(02:09):
is pretty much a square, but I picture it is
being a man with a like a toga and a
belt kind of on the diagonal anyway. Um, so if
you count the stores in our eye and you can
see about eleven if you live in a place with
a lot of light pollution, but wander on out into
some sort of cleary night paradise for looking at stars,
and you can see as many as fifty. So that's

(02:31):
just one hand you measure that we're going to give
to you for compared to just all the stars in
the sky on top of that. Because I don't know
about you, but I um, I grew up in a
really rural area part of Tennessee. There's just out in
the middle of nowhere, and I remember just walking out
at night and just seeing just this pit of stars
above me. You know, it was just like the universe

(02:52):
just seemed to go on forever, and you felt like
you could just be sucked up into it in any
given moment, right Like you felt like you're almost in
a planetarium, right those are was here. Grew up in
places with a lot of light pollution, it's like that
like that, yeah, except with like coyotes in the woods
around you. And yeah, I used to actually kind of
frighten me because I also watched unsolved mysteries and was

(03:14):
just convinced I was going to be abducted by aliens.
At any given moment, if I saw them speeding, you know,
through the stars in a little UFO or something, they
would see me and they'd have to come get me.
And now I'm not afraid of all that stuff anymore,
and i find myself missing, you know, that kind of
night sky. Serious astronomers obviously hate light pollution that, huh, right,
because yeah, they're looking for things up there, not so

(03:37):
much UFOs or Orion's belt, which they're you know, that's
just bush league stuff to them. They're more into things
like messing clouds and titans atmosphere, you know, and and
what's going on with Saturn's rings and the hunt for exoplanets,
and the atmosphere itself, like even on like a clear day,
you know, the the atmosphere itself can throw instrumentation out
of whack. That's when we send up satellites with telescopes

(03:59):
to get get out of all that. But throwing light
pollution that just cuts down visibility even more. You're trying
to operate an observatory and there's like a stuckies like
down the block with all its lights on. I mean,
that can interfere with the instrumentation as well. I mean,
you need your darkness to see the stars. In case
you haven't gathered already. We advocate darkness this podcast Darkness

(04:22):
is Your Friend people. And another group that advocates darkness
is the International Dark Skies Association dark Skies dot Org.
On a more localized level, there's say Flagstaff Dark Skies Coalition.
Flagstaff Arizona is important because there's a really notable observatory there.
So the flag Staff Dark Sky's Coalition is made of

(04:42):
um a lot of efforts to just cut down on
how much light is going on in the surrounding area,
because the more lightning surrounding area, the more obscured view
of the stars you have. So you have people like
knocking on doors and saying, please sir, turn off that
really annoying light. Yeah. That, and like you know, knocking
on the doors of like you know, local business associations

(05:05):
and you know city government, county ordinances and all. And
you get it to where people are using lights more
responsibly at night, or they're using them in the right way.
For instance, you know you want to light a parking lot,
why not just direct the light at the parking lot.
No need to have it going off in every direction.
You know, it's simple things like that, Simple things, Robert. So,

(05:26):
there are a few different kinds of light pollution that
mess up the darkness for us, all um. And one
of those sky glow, and skyglow is just just imagine
looking down upon a city at night, major metropolitan area
of your choice, like I don't know, Los Angeles, maybe Atlanta,
and what you're gonna see is just kind of this
brilliant blanket of skyglow and you're not going to see

(05:47):
the darkness. Yeah, it's like any of those, uh for
me films where you see people going up to like
the Hollywood Sign and they're looking out at l A
and it just looks like this glowing golden world. You know,
that's just light pollution that it's And then this is
my favorite kind of light pollution. You have light trespass.
And I love Chevy Chase, and this makes me think

(06:09):
of a Chevy Chase movie Christmas Vacation when he painstakingly
puts up all of his Christmas lights and finally, oh yeah, Chevy,
you finally get it right, or Clark, I should say,
and he pretty much blinds the whole neighborhood so this
is like Chevy's light is trespassing on all of the
other neighbors and their their nice darkness. And I have

(06:31):
to say, I'm a fan of Christmas lights, so I
was a little conflicted by this type of light pollution.
Or it's something like if you live next to a
football stadium and every night is Friday nightlights for you, Yeah,
why can't they play football in the daytime or in
the dark. Why can't they play football in the dark?
Excellent glow in the dark materials out there. They're used
to getting her what's a couple of more stub toos, right,

(06:54):
and then used to like glare. And this is just
when lights are aiming directly into your eyes, like those
really fancy xenon high intensity discharged lights that tend to
blind me when I'm driving. Although I did find a
study that says said lights um may annoy oncoming drivers
like myself, but they don't disable them. I think the

(07:15):
University of Michigan to study on it. Yeah, that's always
a bad sell with you know, these headlights will disable
other drivers, but um, and then you have stuffite like clutter,
And this is this is a kind of late pollution
where somebody just got a little bit too happy and
putting up street lights and there's an overabundance of them,
or maybe there's a building that's lit up like daytime
at midnight. So besides being wasteful and making astronomers mad,

(07:41):
it has some serious effects on our health and our
circadian rhythms. That's right. A lot of the creatures on
this planet have evolved to live in um in periods
of night, in periods of day where they spend most
of their time. It depends, but still they're they're dealing
with that system. And again, when you you know, illuminate

(08:02):
a BP station with the light of a thousand suns,
you're messing up that system. Right, So circadian rhythms depend
on light in darkness, and then circadian rhythms impact behavior
down the line, like sleeping, like mating, like migration, feeding,
I mean, just basic activity levels. Even if you have

(08:22):
an animal living in a national park or somewhere out
in the wild, you still have residual effects from you know,
nearby urban development. So light is everywhere? Is this a surprise?
Not so much so. It seems like artificial light is everywhere.
You just can't get away from it. So let's talk
about some of these poor animals and how they're affected.
One of the ones that stuck with me about light
pollution how animals are affected was on baby sea turtles.

(08:46):
Did you read that and Jessica Chiefman's fine fine article?
I did, and I'm familiar with that one from family
beach visits in the past. Sad stuff. Yeah, So when
these baby sea turtles hatch on a beach, they're supposed
to hit to the water right nice, you know, some
moonlight playing over the waves, that's how they know where
the ocean is right. But then you have things like

(09:08):
bright beach lights illuminating the fine white sand, and the
port turtle gets confused and sometimes will even head off
in the wrong direction, and what do you know, he
gets hit by a passing car. He ensconces himself in
a seaside resort. It's bad news for Yeah, light pollution
not good for the baby turtles. And you have things
like owls, and owls like you guys know, are nocturnals.

(09:33):
So they take advantage of night to hunt more and
it increasingly drives the prey into hiding. They're out there
to catch animals that live at night, and if you
have it lit up like day, those uh that those
those animals are going to be gone. And then you
stuff like bioluminescent species, and these are just the organisms
that light up per a chemical reaction to um. On land,

(09:54):
this might be fireflies and fungus, and then in the
water you have fish and alerga that light up. And
the problem for these tireless bioluminescent species is that all
of a sudden they have competitors, which is the artificial lighting,
and it poses a problem. There's another animal of a
special note. Humans, Humans of course have to deal with

(10:17):
periods of light and darkness like everything else. Most of
us tend to spend that time working during the day
and sleeping at night. Right, It's interesting. It looked at
a number of different studies and some of this is
mentioned in our House Stuff Works article by Jessica Toothman
as well. It's it seems like it's a careful balance.
You know, It's like we need a certain amount of
light and and that's that's pretty obvious because you know,

(10:39):
you have a lot of people really have to have
their light or they grow depressed. It's you know, seasonal
effective disorder, etcetera. People to live in the far North. Um,
you know, places like you know in Alaska or you know,
parts of Scandinavia, they actually you know, have to have
to have light treatment. You know, they like wake up
in the morning, um, you know, turn on a certain
kind of lights to help raise their you know, their

(11:02):
their levels, you know, stop them drinking all the time.
So yeah, we take that for granted that humans need
light to survive because you know, we've all seen movies
where people live underground and turn into some sort of
grotesque monster. Right, but you know there's a lot of
ill effects as well to not getting enough darkness. We
really need those periods of darkness to remain healthy. Um.

(11:24):
This is how it works, all right. We perceive light
through our retiness, right, and this then suppresses the penneal gland,
which pumps out melotonin, right, a hormone that regulates estrogen
and testosterone. Okay, so if you're not getting enough darkness,
you're not going to produce enough melatonin alright, Your melotonin
or at least your melotonin levels are going to be

(11:45):
significantly lower. To break that down, like they say that
less than forty minutes of basking under an incandescent light
bulb can reduce some melotonal levels of up right, and
you want more melotonin because this is what regulates your
circadian right right, it helps right late your sleep cycle exactly. Um,
A number of you may take and may even take
it as a supplement. I take it at the supplement

(12:06):
to sleep at night. See. And additional studies have linked
artificial lighting to breast, colorectal prostate cancer. And there was
even an interesting interesting study from the Journal of Pennial Research.
Who knew there was a turnal with that now that's
it's pretty specific. Indicate that women in developed nations are
five times more likely to get breast cancer that women

(12:28):
in underdeveloped countries. And they're thinking there's a link somewhere
in there that's related to the amount of light. Yeah,
they're just saying that people in these more developed countries
are like a lot of us, are living in environments
where you look out the window, you know there's a
gas station gleaming in the night. You know, you look
overhead and you just see the glow of the city
lights everywhere. You know, you get up in the night,
you turn on six or seven lights just to go

(12:50):
use the restroom. Right, But if you live in a
less developed nation, you're more likely to say, get up
in the night and go, you know, relieve yourself in
the darkness. I use the restroom in the darkness. Anyway.
Who turns on the light to go to the bathroom
at night? I mean, that is so stupid. I always
make it a game to see if I can do
as much as possible in the darkness. Well, I like
to turn on the lights when I use the restroom. Well,

(13:11):
then you're gonna have to pay the consequences with your
melitone in there, buddy, that's true. But this brings us
to the point. What can we do to cut down
on light pollution? Right? You can do a lot of stuff, alright,
name one, give me give me something, Uh, turn off
the light? Yeah, that's that's a big one, just if
you're not using it. I mean it's kind of like,
you know, when you're a kid and your dad's tone,

(13:31):
you turn off the light when you leave the room.
Another one is, do you you don't really need a
high watt bulb every outlet, you know, even if they
are energy savor bulbs. Cut down the wattage of you're
not going to be performing, you know, minor surgery by it. Dimmers.
Dimmers are your friend, I understand. They're also fixtures can
be really important. Um, like I mentioned earlier, make sure

(13:53):
that you have a fixture that covers enough of the
light and where it's focused on what you need it for.
You know, if you have a floodlight pointed at what
you're flooding the light on, it doesn't need to just
go everywhere. Yeah. And incidentally, didn't you find something about
floodlights creating pockets of darkness anyway? That was something brought
up by the International Dark Skies Association, because you know,

(14:13):
one argument against the whole, you know, controlling light pollution
thing is people say, hey, I live in a terrifying
neighborhood and I am going to keep these floodlights on
to help protect my home and lights make people feel safe. Yeah,
and and it's you know, you look at any safety
list and that's one of the big ones. Illuminate your house.
I mean, I stand by that. But they also point

(14:33):
out that if you have like a lot of artificial
lighting going on in the area, you also end up
creating these pockets of darkness, which are really kind of
excellent hiding places because because anybody driving by your lights
gonna adjust to the really bright lights and those and
wherever there's darkness, it's just gonna be deep, impenetrable darkness.
So maybe something like motion sensor lights would be a
better call. Yeah, that would be That would be a

(14:55):
perfect call. And you know the advantage of all this too,
is it also cuts down on your your electrac to
build at the end of the month. What about Christmas lights?
They're necessary? Yeah? I don't know that they're necessary, but
they do make me feel festive. Yeah, where did your
Christmas lights? On a scale of like one being like
total natural darkness, intending like Griswold family Christmas, where do

(15:17):
you where do you fall? Um? I would give them,
I'm and I think they fall right in the middle
like a five. They're very tasteful too. I only use
white lights. Well, that's that's not as extreme an example
of light pollution as as one of my favorite examples
something they apparently had an eight in the nineteen eighties
here in Atlanta called Light Up Atlanta. Have you heard

(15:39):
of this? Um? David Cross references that you know comedy
Batty did, And basically it seems like what what this
consisted of is they would turn on all the lights
in downtown Atlanta, just like all in these you know,
high rise buildings just lighted up, and then they would
block off the streets and people would just flow in
from all you know this around areas and to look

(16:01):
at the lights, to look at the lights and drink
in the streets and listen to two bands play and whatnot. Really,
so it's just a little up building that people hold,
bunch of lit up buildings like the city they're lighting
up Atlanta, And and I guess, you know, sea turtles
are just wandering in, you know, from as far as
close the Pacific Ocean to you know, die in the streets.

(16:22):
So what I'm getting from this podcast is are we
better off in the dark? Well, maybe not totally dark,
but a lot more dark. Yeah, I'm thinking a lot
of us could probably use a little more darkness in
their life. And I mean that in a illumination way
and not enough. So if you want to read more
about lightness, darkness, and anything in between, check out how

(16:42):
stuff works dot com or visit the blogs that blogs
dot how stuff works dot com and you can read
about everything from flu ridden Mall Santas to robotic book Sniffing.
Thanks for listening. Guys podcast is over. Turn Out the
Lights m for more on this and thousands of other topics.

(17:06):
Is it how stuff works dot Com. Want more how
stuff works, check out our blogs on the house stuff
works dot com home page

Stuff To Blow Your Mind News

Advertise With Us

Follow Us On

Hosts And Creators

Robert Lamb

Robert Lamb

Joe McCormick

Joe McCormick

Show Links

AboutStoreRSS

Popular Podcasts

Stuff You Should Know

Stuff You Should Know

If you've ever wanted to know about champagne, satanism, the Stonewall Uprising, chaos theory, LSD, El Nino, true crime and Rosa Parks, then look no further. Josh and Chuck have you covered.

Dateline NBC

Dateline NBC

Current and classic episodes, featuring compelling true-crime mysteries, powerful documentaries and in-depth investigations. Follow now to get the latest episodes of Dateline NBC completely free, or subscribe to Dateline Premium for ad-free listening and exclusive bonus content: DatelinePremium.com

Music, radio and podcasts, all free. Listen online or download the iHeart App.

Connect

© 2025 iHeartMedia, Inc.