“I see Pluto! But where is Mars?” That is a translated quote from my three-year-old self one night during a trip to Mexico, which has since passed into family legend. I couldn’t actually see Pluto with my naked eyes, but my over-imaginative brain had turned one of the thousands of stars I saw into the dwarf planet.
I don’t remember ever noticing any comparable beauty in the sky upon returning home to Brookline. I am lucky to have had that experience in Mexico; I soon realized that unless one travels away from the greater Boston area, they will not see many stars in the night sky.
According to a light pollution map based on data from the World Atlas of Artificial Night Sky Brightness, the whole greater Boston area, including Brookline, has an eight to nine on the Bortle light pollution scale. That’s the highest amount of light pollution the sky can have in a region, compared to a one, the sky in its natural, pure black state. The Boston area’s bright buildings and streetlights are to blame for its high rating. When their light enters the atmosphere, it hits other particles and reflects back to Earth, creating skyglow and making the sky a hazy grey instead of its natural black, per a study from the International Union for Conservation of Nature (IUCN). This makes stars all but invisible and has a multitude of consequences that go way beyond aesthetics.
In addition to preventing people from having the truly incredible experience of looking at the galaxy, the presence of light pollution can have serious ecological effects. Most animals have evolved to have some sort of circadian rhythm: a cycle based on day and night that animals’ sleep patterns, behavior and hunting and mating habits depend on. Over 60 percent of mammals are nocturnal, and excessive amounts of light pollution present in cities like Boston can confuse and harm many species.
What can we do about this? According to the IUCN study, outdoor lights with a colder temperature that (counterintuitively) emit warmer colors of light like yellow or orange improve animals’ night vision. Boston started transitioning to light-emitting diode (LED) street lights in 2010. They are cheaper than “traditional lighting sources”, reduce carbon emissions and allow us to “see colors more clearly,” according to the city’s website.
These factors are, of course, meaningful, but it seems that light pollution was barely, if at all, taken into account in making this big change. The lower cost of LED street lights means governments have no problem placing more of them than are needed and care less about limiting them. Many LED street lights emit light with a very high color temperature of 4000 Kelvin (K) to optimize visibility, but the IUCN study found that lights should not exceed 2700 K for safety, wellness and the environment. The gap between the two temperatures demonstrates that cities aren’t putting enough thought into cutting down on their light pollution.
As someone interested in astronomy from a young age, I believe everyone would benefit from seeing a clear starry sky every night. The gray slate hanging above us very poetically resembles a ceiling, presenting a metaphor of limiting imagination and progress. With an unpolluted sky, we could have a constant natural wonder to enjoy nightly. Seeing the limitless nature of space would boost people’s curiosity immeasurably, and would especially improve the overall development of children who would be able to see whole galaxies without any tools regularly.
A middle ground can be found between cities’ criteria for lights and scientific findings about light pollution, like installing LED lights of lower color temperatures. Some measures can be taken that don’t affect the lights’ function at all. For example, covers can be placed above bright street lights so that no light goes up to the sky, but rather only the street is illuminated, reducing skyglow. Large cities like Boston must also put firmer regulations on commercial lighting at night in place so that unnecessary illumination is eliminated.
Light pollution isn’t a popular topic of discussion in most circles, but it is important to me and something that more of the world must pay attention to. Eighty percent of people in the U.S. live in urban areas and are therefore significantly affected by light pollution. Reducing it would help the environment and promote education about astronomy and other subjects, while increasing natural beauty. The possibilities that would come with eliminating it would be as endless as a clear night sky and would improve countless lives.
