WASHINGTON – Are the street and security lights the Western world takes for granted causing breast cancer,killing sea turtles and blocking views of the constellations?
This week scientists said: Well,maybe.
“There are a lot of people in the world who don't know the difference between night and day,” said David L. Crawford,an astronomer and co-founder of the International Dark-Sky Association,at a conference on nighttime light held here this week.
More than 100 scientists,lighting technicians and government workers registered for the two-day conference hosted by the Carnegie Institution,a nonprofit research center.
George C. Brainard,a professor of neurology and pharmacology at Jefferson Medical College in Philadelphia,said some research points to a rise in breast cancer for women living in industrialized countries.
The bombardment of light may prevent the brain from producing melatonin,a hormone some researchers think combats cancer,Brainard said.
“Melatonin follows the pattern of dark time,” he added.
But Brainard didn't declare a direct link between breast cancer and street light. He said additional research is needed to confirm that “if light can be beneficial,then if it's not used correctly,it can harm.”
Crawford,whose organization planned the event,”The Night: Why Dark Hours Are So Important,” said the growing number of bright lights stretched across the world obscures the circadian rhythm,the 24-hour cycle on which most organisms operate.
“Do you see the glare and the clutter,why do they do that?” he asked the crowd inside the dark auditorium where the meeting took place.
Lorna Patrick,a biologist with the U.S. Fish and Wildlife Service in Florida,is concerned about for baby sea turtles,which she said face death when street lights neighbor beaches.
Upon hatching,the young head for the ocean because usually it's the brightest light source,she said. But that has changed.
“We have found dead hatchlings at the bottom of street lights,” she said.
That change is one of many new problems facing animal life as lights get brighter.
“We don't really know what will happen,but there could be an impact on population,” said Bryant Buchanan,who studies frogs and salamanders at Utica College in New York.
Buchanan said his research found changes in the growth of frog larvae that received too much light. The frog larvae produce melatonin during darkness,just like humans.
As for the constellations,the stars and planets,earth light might one day block them,too.
Some scientists said future generations may see them only in textbooks.
To test that theory,astronomer Stephen M. Pompea and others at the GLOBE program in Tucson,Ariz.,asked people to log on to the program's Web site during two weeks last year to report on the visibility of the constellation Orion from their home.
Eighteen-thousand people from 96 countries logged on,and 4,500 provided observations,which Pompea said was a good result. There will be a similar observation next month.
A solution might arrive if more people knew about this problem,Pompea said.
“There's a lack of education,not resistance,” he said.
To see additional images of the United States,visit the International Dark-Sky Association Web site.