Roughly half of the stars visible in the 1990s can no longer be seen in Pittsburgh’s night sky. The stars aren’t going anywhere — so why can’t we see the Milky Way?

Light pollution — the presence of artificial light that interferes with the natural darkness of nighttime — is on the rise in Pittsburgh.

The Pittsburgh Chapter of the International Dark Sky Association met on Carnegie Mellon’s campus on Oct. 22 to discuss several projects to evaluate light pollution in Pittsburgh — notably, a grant received by two Carnegie Mellon faculty members to map the distribution of light pollution in the city.

Light pollution has subtle but damaging effects. Primarily, it interferes with natural rhythms based on light and darkness — everything from disrupting human sleep cycles and changing the amount of melatonin our bodies produce to confusing nocturnal animals and impeding their mating cycles. However, these effects are not well understood, in part due to a shortage of comprehensive scientific data on light pollution.

As previously reported in The Tartan, Stephen Quick of the School of Architecture’s Remaking Cities Institute and Diane Turnshek of the physics department will lead a project using quadcopter drones to create a high-resolution light pollution map of Pittsburgh, as the city seeks to evaluate the light pollution impact of new street lamps. In addition to the International Dark Sky Association, Quick and Turnshek will be working with the City of Pittsburgh and the Amateur Astronomers Association of Pittsburgh to implement the project and raise awareness for issues of light pollution within the city.

The chapter is also coordinating the creation of “before” and “after” camera photos of Pittsburgh’s night sky by collecting photos from several decades ago and recreating them in the same places around the city.

While large-scale light pollution surveys have existed for years, it’s been difficult to study the local effects of light pollution because measurements are usually taken from satellites. These data are too low-resolution to be useful for a single city trying to determine highly localized light pollution hotspots.

“Many researchers are waiting for a good lighting survey of the city to put to use in their studies,” reads the Metro21 grant. “This type of survey has never been done before at the 10-meter resolution we are proposing... Pittsburgh will be first.”

In addition to initiatives gathering scientific data, the chapter’s other goal is “to create a cultural shift from fearing the dark to embracing it.” Members of the chapter give talks around the city and attend community events to raise awareness for light pollution and encourage participation in community initiatives. A new and unique outreach initiative will be a partnership with local literary non-profit Parsec. Aiming to facilitate the cultural shift through storytelling, the upcoming edition of Parsec’s annual fiction anthology Triangulation will consist of short stories centered around the theme Dark Skies.

Additional information about dark sky initiatives in Pittsburgh can be found at pghconstellation.com and idapgh.org.