full transcript
From the Ted Talk by Diane Knutson: Why we need darkness
Unscramble the Blue Letters
This meadowlark pechres on a prairie flower sgniing its mating song. It's crutmosay for meadowlarks to sing toward the rinsig sun. This one, however, was mistaken by the lights of Rapid City at 2 AM. Despite being 60 miles south of the Rapid City bodrer and well within the boundaries of Wind Cave National Park, this songbird was singing out much too late to artactt a mate. Have you ever tried atttricnag a mate by calling them at 2 AM? (Laughter) My mother told me nothing good happens after midnight. (Laughter) So why was this sngbiord so confused, mistaking the bright lights of ripad City for the rising sun at 2 AM? iomrpepr ligthnig and the over-illumination of residential neighborhoods, business signage, and street lights brighten our night sky, creating an orange hue above the city for miles outside its border. Over 100 years ago, all creatures could look up and see a slcutacaepr srtray night sky. But now, eight out of ten children will never see the Milky Way from where they live. Light pollution doesn't only impact our view of the universe, it also itcamps our environment, our individual htaleh, and energy cipmsnotuon. The three main components of light pollution include sky glow as well as galre and light trespass, which I will also explain. Glare is the excessive brightness that causes us vsiaul discomfort. We often illuminate areas in attempt to increase safety. As children, we're afraid of the dark, so we flip on a night switch because "the night is dark and full of terrors." And as adults, we do that now on a much gnaedrr scale. A 2015 study published in the Journal of Epidemiology and Community Health looked at statistics where researchers studied lights that were turned on at certain hrous, dmimed, or turned off completely, and found that it had no impact on traffic cnllioosis or crime. I want you to take a very close look at this picture. Mentally note what you see. With properly sheldeid lights, we can actually see what was there the eintre time. Brighter does not mean safer. The third component of light pollution is light trespass. To understand this, I want you to envision your bedroom. Could you sleep at night with no curtains? Or do you need those blackout shdeas tucked into every single crevice of that window pane, just in order to get a good night's sleep? If so, that is because of light trespass, the shining of light where it's unneeded, and unintended, and unwanted, from another source ogrinainitg somewhere other than your own. Now that we've lokoed at what causes light pollution, let's take a look at where light pollution is. Here is a global map with light pollution ditcpeed by various colors. Let's zoom in to our local area of impact. This is Rapid City. We are on the front lines of a battle of lights versus dark. Zooming in closer to South Dakota, I want you to envision that you're downtown at Main Street srauqe, you've got your baeknlt, your chair, you're ready to stargaze. And then you look up, and you rizelae you can see relatively very few stars. You cannot even see the Big Dipper. So you pack up all your belongings, you get in the car, you drive to the city limits, where now you're in the orange zone, where eight out of ten Americans live, and we have a lcaol observatory. You look up, you still cannot see the Milky Way. You keep on driving, you go deep into the Black Hills nanaotil Forest, and then you see it, the sky glow the meadowlark was singing toward. To get to a naturally dark sky, you would have to drive two hours north, to the corner of northwest South Dakota, an area called Slim Buttes, which has a Class 1 dark sky, a ntaurally lit sky, where the srats from the Milky Way shnie so bihgrt it will cast a shodaw of you on the ground. Rapid City is a Class 9 sky, the brightest depicted on the map, where light pollution is 100 up to 200 times bigrhetr than our natural darkness. You cannot make out the North Star. But the thing is Rapid City is not alone. Light pollution plagues every meodrn city and town. The good news, however, is that light pollution could possibly be the simplest poelrbm to solve and could literally be done overnight, simply with the flip of a switch. So if at any point in this presentation you decide that it's important to protect our dark skies, I ask you to turn off your light in front of you, simply by twisting it off. Now just like in real life, here's a hint: You can ask your neighbor to shut off their light as well if their light is trespassing into your area and iniiithbng your view of a TEDx presentation. (Laughter) Even if we all turn out our lights, more is needed to be done. One hundred years ago, this is the view from sylinke Drive you would have seen. Today, this is a picture taken this year during the Rapid City Dark Earth Hour. Which one do you prefer? So what are we going to do if we all turn out our lhtigs and it's still bright? We need to protect nocturnal habitats, stargazing opportunities, and our nocturnal plants and anmilas. Now, bats. There's an idea. I know what we can do. Let's call Batman! He'll know what to do! Send the bat signal! Right? Oh, wait, maybe he didn't get the memo either. So let's sfiht our foucs to nocturnal plants. In the Black hlils, there's a moonflower that blooms only in dark nights. (Music) (msuic ends) Earth evolved with bright days and dark nights. Another example of nocturnal life that needs darkness is the owl. Owls see five times brighter than we do as humans because in their eyes they have light detecting rods that are nuebrmed at one million rods per square miemtlelir. Just because we can see with lights at night doesn't mean other creatures can. But even though we can see with acariiiftl light at night, doesn't mean that it's htleahy for us. The American Medical Association states "all creatures need darkness to siruvve." As light travels through our eye, it goes to a tract of a nucleus cseltur of toshadnus of cells that send messages to our glands. Those glands secrete a naturally onuriccrg hormone called melatonin. The great thing about melatonin is it has great antioxidant qualities that rid our brian and body of free raaldcis that cause damage to our brain and body. The Journal of Epidemiology Research shows that exposure to artificial light at night has been linked to an increase in Alzheimer's, breast cancer, obesity, and depression. Let's take a look now at what our future holds. The map I showed you of South Dakota is a one from 1997, when in all reality, tonight's dark skies is much more cseloly, really, like the map of 2025. In only eight years, it's estimated that just eight dark sky pleacs will remain in the utiend States. So if we can't call bmatan, what are we supposed to do? OK, I have another idea, hold on with me, this is a little bit better. Let's join the Dark Side. Maybe Kylo Ren and Darth Vader had it right all along. But all jiokng aside, there really is something about the color spectrum. This is a color kvlein chart, rating color by its temperature. The International Dark Sky Association rates colors below 3,000 Kelvins as dark sky friendly because it doesn't impiar night vision. What else can we do? Address our fixtures, because dark skies doesn't have to mean dark ground. We can point lights down, where the light is intended. The International Dark Sky aioisactson estimates that all of the outdoor lighting wastes 30 peenrct of light that goes outward and upward where it is not needed or intended, wasting money and cneiartg more carbon emissions. In addition, this is a sample of a front porch light that could be converted into a full cutoff fixture, reducing glare, sky glow, and light trespass. Streetlights that point light outward and upward could be retrofitted to point the light downward. Paris, the City of lihgt, took sinovlg light pollution to a whole new level. They eteancd a lights-out curfew of 1 AM or one hour past the last employee's duatprere time. I challenge you to find your reason for #LightsOut. I wish you all a very dark night. (Applause)
Open Cloze
This meadowlark _______ on a prairie flower _______ its mating song. It's _________ for meadowlarks to sing toward the ______ sun. This one, however, was mistaken by the lights of Rapid City at 2 AM. Despite being 60 miles south of the Rapid City ______ and well within the boundaries of Wind Cave National Park, this songbird was singing out much too late to _______ a mate. Have you ever tried __________ a mate by calling them at 2 AM? (Laughter) My mother told me nothing good happens after midnight. (Laughter) So why was this ________ so confused, mistaking the bright lights of _____ City for the rising sun at 2 AM? ________ ________ and the over-illumination of residential neighborhoods, business signage, and street lights brighten our night sky, creating an orange hue above the city for miles outside its border. Over 100 years ago, all creatures could look up and see a ___________ ______ night sky. But now, eight out of ten children will never see the Milky Way from where they live. Light pollution doesn't only impact our view of the universe, it also _______ our environment, our individual ______, and energy ___________. The three main components of light pollution include sky glow as well as _____ and light trespass, which I will also explain. Glare is the excessive brightness that causes us ______ discomfort. We often illuminate areas in attempt to increase safety. As children, we're afraid of the dark, so we flip on a night switch because "the night is dark and full of terrors." And as adults, we do that now on a much _______ scale. A 2015 study published in the Journal of Epidemiology and Community Health looked at statistics where researchers studied lights that were turned on at certain _____, ______, or turned off completely, and found that it had no impact on traffic __________ or crime. I want you to take a very close look at this picture. Mentally note what you see. With properly ________ lights, we can actually see what was there the ______ time. Brighter does not mean safer. The third component of light pollution is light trespass. To understand this, I want you to envision your bedroom. Could you sleep at night with no curtains? Or do you need those blackout ______ tucked into every single crevice of that window pane, just in order to get a good night's sleep? If so, that is because of light trespass, the shining of light where it's unneeded, and unintended, and unwanted, from another source ___________ somewhere other than your own. Now that we've ______ at what causes light pollution, let's take a look at where light pollution is. Here is a global map with light pollution ________ by various colors. Let's zoom in to our local area of impact. This is Rapid City. We are on the front lines of a battle of lights versus dark. Zooming in closer to South Dakota, I want you to envision that you're downtown at Main Street ______, you've got your _______, your chair, you're ready to stargaze. And then you look up, and you _______ you can see relatively very few stars. You cannot even see the Big Dipper. So you pack up all your belongings, you get in the car, you drive to the city limits, where now you're in the orange zone, where eight out of ten Americans live, and we have a _____ observatory. You look up, you still cannot see the Milky Way. You keep on driving, you go deep into the Black Hills ________ Forest, and then you see it, the sky glow the meadowlark was singing toward. To get to a naturally dark sky, you would have to drive two hours north, to the corner of northwest South Dakota, an area called Slim Buttes, which has a Class 1 dark sky, a _________ lit sky, where the _____ from the Milky Way _____ so ______ it will cast a ______ of you on the ground. Rapid City is a Class 9 sky, the brightest depicted on the map, where light pollution is 100 up to 200 times ________ than our natural darkness. You cannot make out the North Star. But the thing is Rapid City is not alone. Light pollution plagues every ______ city and town. The good news, however, is that light pollution could possibly be the simplest _______ to solve and could literally be done overnight, simply with the flip of a switch. So if at any point in this presentation you decide that it's important to protect our dark skies, I ask you to turn off your light in front of you, simply by twisting it off. Now just like in real life, here's a hint: You can ask your neighbor to shut off their light as well if their light is trespassing into your area and __________ your view of a TEDx presentation. (Laughter) Even if we all turn out our lights, more is needed to be done. One hundred years ago, this is the view from _______ Drive you would have seen. Today, this is a picture taken this year during the Rapid City Dark Earth Hour. Which one do you prefer? So what are we going to do if we all turn out our ______ and it's still bright? We need to protect nocturnal habitats, stargazing opportunities, and our nocturnal plants and _______. Now, bats. There's an idea. I know what we can do. Let's call Batman! He'll know what to do! Send the bat signal! Right? Oh, wait, maybe he didn't get the memo either. So let's _____ our _____ to nocturnal plants. In the Black _____, there's a moonflower that blooms only in dark nights. (Music) (_____ ends) Earth evolved with bright days and dark nights. Another example of nocturnal life that needs darkness is the owl. Owls see five times brighter than we do as humans because in their eyes they have light detecting rods that are ________ at one million rods per square __________. Just because we can see with lights at night doesn't mean other creatures can. But even though we can see with __________ light at night, doesn't mean that it's _______ for us. The American Medical Association states "all creatures need darkness to _______." As light travels through our eye, it goes to a tract of a nucleus _______ of _________ of cells that send messages to our glands. Those glands secrete a naturally _________ hormone called melatonin. The great thing about melatonin is it has great antioxidant qualities that rid our _____ and body of free ________ that cause damage to our brain and body. The Journal of Epidemiology Research shows that exposure to artificial light at night has been linked to an increase in Alzheimer's, breast cancer, obesity, and depression. Let's take a look now at what our future holds. The map I showed you of South Dakota is a one from 1997, when in all reality, tonight's dark skies is much more _______, really, like the map of 2025. In only eight years, it's estimated that just eight dark sky ______ will remain in the ______ States. So if we can't call ______, what are we supposed to do? OK, I have another idea, hold on with me, this is a little bit better. Let's join the Dark Side. Maybe Kylo Ren and Darth Vader had it right all along. But all ______ aside, there really is something about the color spectrum. This is a color ______ chart, rating color by its temperature. The International Dark Sky Association rates colors below 3,000 Kelvins as dark sky friendly because it doesn't ______ night vision. What else can we do? Address our fixtures, because dark skies doesn't have to mean dark ground. We can point lights down, where the light is intended. The International Dark Sky ___________ estimates that all of the outdoor lighting wastes 30 _______ of light that goes outward and upward where it is not needed or intended, wasting money and ________ more carbon emissions. In addition, this is a sample of a front porch light that could be converted into a full cutoff fixture, reducing glare, sky glow, and light trespass. Streetlights that point light outward and upward could be retrofitted to point the light downward. Paris, the City of _____, took _______ light pollution to a whole new level. They _______ a lights-out curfew of 1 AM or one hour past the last employee's _________ time. I challenge you to find your reason for #LightsOut. I wish you all a very dark night. (Applause)
Solution
- attract
- blanket
- percent
- artificial
- stars
- places
- grander
- focus
- modern
- shine
- departure
- brain
- visual
- inhibiting
- healthy
- problem
- starry
- shadow
- local
- thousands
- creating
- attracting
- square
- united
- health
- impacts
- entire
- border
- hills
- numbered
- association
- national
- occurring
- singing
- shift
- lights
- naturally
- enacted
- improper
- millimeter
- kelvin
- shades
- joking
- light
- animals
- dimmed
- shielded
- consumption
- collisions
- skyline
- songbird
- impair
- cluster
- rapid
- realize
- originating
- depicted
- lighting
- solving
- hours
- spectacular
- batman
- rising
- glare
- survive
- brighter
- closely
- looked
- music
- radicals
- customary
- perches
- bright
Original Text
This meadowlark perches on a prairie flower singing its mating song. It's customary for meadowlarks to sing toward the rising sun. This one, however, was mistaken by the lights of Rapid City at 2 AM. Despite being 60 miles south of the Rapid City border and well within the boundaries of Wind Cave National Park, this songbird was singing out much too late to attract a mate. Have you ever tried attracting a mate by calling them at 2 AM? (Laughter) My mother told me nothing good happens after midnight. (Laughter) So why was this songbird so confused, mistaking the bright lights of Rapid City for the rising sun at 2 AM? Improper lighting and the over-illumination of residential neighborhoods, business signage, and street lights brighten our night sky, creating an orange hue above the city for miles outside its border. Over 100 years ago, all creatures could look up and see a spectacular starry night sky. But now, eight out of ten children will never see the Milky Way from where they live. Light pollution doesn't only impact our view of the universe, it also impacts our environment, our individual health, and energy consumption. The three main components of light pollution include sky glow as well as glare and light trespass, which I will also explain. Glare is the excessive brightness that causes us visual discomfort. We often illuminate areas in attempt to increase safety. As children, we're afraid of the dark, so we flip on a night switch because "the night is dark and full of terrors." And as adults, we do that now on a much grander scale. A 2015 study published in the Journal of Epidemiology and Community Health looked at statistics where researchers studied lights that were turned on at certain hours, dimmed, or turned off completely, and found that it had no impact on traffic collisions or crime. I want you to take a very close look at this picture. Mentally note what you see. With properly shielded lights, we can actually see what was there the entire time. Brighter does not mean safer. The third component of light pollution is light trespass. To understand this, I want you to envision your bedroom. Could you sleep at night with no curtains? Or do you need those blackout shades tucked into every single crevice of that window pane, just in order to get a good night's sleep? If so, that is because of light trespass, the shining of light where it's unneeded, and unintended, and unwanted, from another source originating somewhere other than your own. Now that we've looked at what causes light pollution, let's take a look at where light pollution is. Here is a global map with light pollution depicted by various colors. Let's zoom in to our local area of impact. This is Rapid City. We are on the front lines of a battle of lights versus dark. Zooming in closer to South Dakota, I want you to envision that you're downtown at Main Street Square, you've got your blanket, your chair, you're ready to stargaze. And then you look up, and you realize you can see relatively very few stars. You cannot even see the Big Dipper. So you pack up all your belongings, you get in the car, you drive to the city limits, where now you're in the orange zone, where eight out of ten Americans live, and we have a local observatory. You look up, you still cannot see the Milky Way. You keep on driving, you go deep into the Black Hills National Forest, and then you see it, the sky glow the meadowlark was singing toward. To get to a naturally dark sky, you would have to drive two hours north, to the corner of northwest South Dakota, an area called Slim Buttes, which has a Class 1 dark sky, a naturally lit sky, where the stars from the Milky Way shine so bright it will cast a shadow of you on the ground. Rapid City is a Class 9 sky, the brightest depicted on the map, where light pollution is 100 up to 200 times brighter than our natural darkness. You cannot make out the North Star. But the thing is Rapid City is not alone. Light pollution plagues every modern city and town. The good news, however, is that light pollution could possibly be the simplest problem to solve and could literally be done overnight, simply with the flip of a switch. So if at any point in this presentation you decide that it's important to protect our dark skies, I ask you to turn off your light in front of you, simply by twisting it off. Now just like in real life, here's a hint: You can ask your neighbor to shut off their light as well if their light is trespassing into your area and inhibiting your view of a TEDx presentation. (Laughter) Even if we all turn out our lights, more is needed to be done. One hundred years ago, this is the view from Skyline Drive you would have seen. Today, this is a picture taken this year during the Rapid City Dark Earth Hour. Which one do you prefer? So what are we going to do if we all turn out our lights and it's still bright? We need to protect nocturnal habitats, stargazing opportunities, and our nocturnal plants and animals. Now, bats. There's an idea. I know what we can do. Let's call Batman! He'll know what to do! Send the bat signal! Right? Oh, wait, maybe he didn't get the memo either. So let's shift our focus to nocturnal plants. In the Black Hills, there's a moonflower that blooms only in dark nights. (Music) (Music ends) Earth evolved with bright days and dark nights. Another example of nocturnal life that needs darkness is the owl. Owls see five times brighter than we do as humans because in their eyes they have light detecting rods that are numbered at one million rods per square millimeter. Just because we can see with lights at night doesn't mean other creatures can. But even though we can see with artificial light at night, doesn't mean that it's healthy for us. The American Medical Association states "all creatures need darkness to survive." As light travels through our eye, it goes to a tract of a nucleus cluster of thousands of cells that send messages to our glands. Those glands secrete a naturally occurring hormone called melatonin. The great thing about melatonin is it has great antioxidant qualities that rid our brain and body of free radicals that cause damage to our brain and body. The Journal of Epidemiology Research shows that exposure to artificial light at night has been linked to an increase in Alzheimer's, breast cancer, obesity, and depression. Let's take a look now at what our future holds. The map I showed you of South Dakota is a one from 1997, when in all reality, tonight's dark skies is much more closely, really, like the map of 2025. In only eight years, it's estimated that just eight dark sky places will remain in the United States. So if we can't call Batman, what are we supposed to do? OK, I have another idea, hold on with me, this is a little bit better. Let's join the Dark Side. Maybe Kylo Ren and Darth Vader had it right all along. But all joking aside, there really is something about the color spectrum. This is a color Kelvin chart, rating color by its temperature. The International Dark Sky Association rates colors below 3,000 Kelvins as dark sky friendly because it doesn't impair night vision. What else can we do? Address our fixtures, because dark skies doesn't have to mean dark ground. We can point lights down, where the light is intended. The International Dark Sky Association estimates that all of the outdoor lighting wastes 30 percent of light that goes outward and upward where it is not needed or intended, wasting money and creating more carbon emissions. In addition, this is a sample of a front porch light that could be converted into a full cutoff fixture, reducing glare, sky glow, and light trespass. Streetlights that point light outward and upward could be retrofitted to point the light downward. Paris, the City of Light, took solving light pollution to a whole new level. They enacted a lights-out curfew of 1 AM or one hour past the last employee's departure time. I challenge you to find your reason for #LightsOut. I wish you all a very dark night. (Applause)
Frequently Occurring Word Combinations
ngrams of length 2
collocation |
frequency |
light pollution |
9 |
rapid city |
7 |
dark sky |
4 |
rising sun |
2 |
sky glow |
2 |
light trespass |
2 |
times brighter |
2 |
nocturnal plants |
2 |
dark nights |
2 |
artificial light |
2 |
dark skies |
2 |
international dark |
2 |
sky association |
2 |
ngrams of length 3
collocation |
frequency |
international dark sky |
2 |
dark sky association |
2 |
Important Words
- addition
- address
- adults
- afraid
- american
- americans
- animals
- antioxidant
- applause
- area
- areas
- artificial
- association
- attempt
- attract
- attracting
- bat
- batman
- bats
- battle
- bedroom
- belongings
- big
- bit
- black
- blackout
- blanket
- blooms
- body
- border
- boundaries
- brain
- breast
- bright
- brighten
- brighter
- brightest
- brightness
- business
- buttes
- call
- called
- calling
- cancer
- car
- carbon
- cast
- cave
- cells
- chair
- challenge
- chart
- children
- city
- class
- close
- closely
- closer
- cluster
- collisions
- color
- colors
- community
- completely
- component
- components
- confused
- consumption
- converted
- corner
- creating
- creatures
- crevice
- crime
- curfew
- curtains
- customary
- cutoff
- dakota
- damage
- dark
- darkness
- darth
- days
- decide
- deep
- departure
- depicted
- depression
- detecting
- dimmed
- dipper
- discomfort
- downtown
- downward
- drive
- driving
- earth
- emissions
- enacted
- ends
- energy
- entire
- environment
- envision
- epidemiology
- estimated
- estimates
- evolved
- excessive
- explain
- exposure
- eye
- eyes
- find
- fixture
- fixtures
- flip
- flower
- focus
- forest
- free
- friendly
- front
- full
- future
- glands
- glare
- global
- glow
- good
- grander
- great
- ground
- habitats
- health
- healthy
- hills
- hold
- holds
- hormone
- hour
- hours
- hue
- humans
- idea
- illuminate
- impact
- impacts
- impair
- important
- improper
- include
- increase
- individual
- inhibiting
- intended
- international
- join
- joking
- journal
- kelvin
- kelvins
- kylo
- late
- laughter
- level
- life
- light
- lighting
- lights
- limits
- lines
- linked
- lit
- literally
- live
- local
- looked
- main
- map
- mate
- mating
- meadowlark
- meadowlarks
- medical
- melatonin
- memo
- mentally
- messages
- midnight
- miles
- milky
- millimeter
- million
- mistaken
- mistaking
- modern
- money
- moonflower
- mother
- music
- national
- natural
- naturally
- needed
- neighbor
- neighborhoods
- news
- night
- nights
- nocturnal
- north
- northwest
- note
- nucleus
- numbered
- obesity
- observatory
- occurring
- opportunities
- orange
- order
- originating
- outdoor
- outward
- overnight
- owl
- owls
- pack
- pane
- paris
- park
- percent
- perches
- picture
- places
- plagues
- plants
- point
- pollution
- porch
- possibly
- prairie
- prefer
- presentation
- problem
- properly
- protect
- published
- qualities
- radicals
- rapid
- rates
- rating
- ready
- real
- reality
- realize
- reason
- reducing
- remain
- ren
- research
- researchers
- residential
- retrofitted
- rid
- rising
- rods
- safer
- safety
- sample
- scale
- secrete
- send
- shades
- shadow
- shielded
- shift
- shine
- shining
- showed
- shows
- shut
- side
- signage
- simplest
- simply
- sing
- singing
- single
- skies
- sky
- skyline
- sleep
- slim
- solve
- solving
- song
- songbird
- source
- south
- spectacular
- spectrum
- square
- star
- stargaze
- stargazing
- starry
- stars
- states
- statistics
- street
- streetlights
- studied
- study
- sun
- supposed
- survive
- switch
- tedx
- temperature
- ten
- terrors
- thousands
- time
- times
- today
- told
- town
- tract
- traffic
- travels
- trespass
- trespassing
- tucked
- turn
- turned
- twisting
- understand
- unintended
- united
- universe
- unneeded
- unwanted
- upward
- vader
- view
- vision
- visual
- wait
- wastes
- wasting
- wind
- window
- year
- years
- zone
- zoom
- zooming