Transitioning to LED Lighting: A Threat to Our View of the Night Sky

To help people understand the importance of dark night skies, I like to tell a story from my childhood about growing up next to a freeway in Los Angeles. I’m a kid from his smoggy 1980s and his 1990s LA. At the time, air quality was notoriously poor. The city at night was also magically lit up. Smog and light pollution created conditions in which few celestial features other than the Moon and sometimes Venus were visible.

I had never seen a dark night sky until I was a teenager, and it was then that I first learned that under the right conditions, the Milky Way could be seen with the naked eye. I did not understand.

Almost 20 years later, while I was in Chile on my first and only professional telescope observation, I stood under a clear southern sky and realized that my ancestors had always seen skies like this. I did. They didn’t have to travel thousands of miles over 24 hours. Dark night skies were their norm. This is how they evolved and how they lived every night. That’s when I realized how much we inner-city kids are denied the bright lights and air pollution of our beloved hometown. We can no longer see the universe like our ancestors did.

At the time I received this revelation, a notable feature of many American cities was the orange-tinged appearance of street lights at night. Many of these are sodium vapor lamps, which emit light at sodium’s natural frequency of 589 nanometers. This meant the light was approximately one wavelength, orange in color, and gave the city a kind of fiery halo in the evening.

The problem with sodium vapor lighting is that it is less energy efficient than newer technologies. When I was in Chile, there was a major policy push to encourage the transition to LED lighting, which significantly reduces energy use. That’s a great idea. The only problem? The transition to LED lighting, driven by policymakers across the United States, did not have the requirement to filter light to only a single frequency, as with sodium lighting. As a result, most of the lighting installed across the country now uses white light.

White light is a combination of different frequencies and mimics sunlight. Animals (including humans) have a different biological response to white light than to orange light. This is because humans are programmed to interpret white light as sunlight, which can disrupt our circadian rhythms.

Of course, light pollution can be a problem at any frequency, especially when the light is not concentrated where it is needed, i.e. on the ground rather than in the sky. Broad-spectrum LED lighting adds to these challenges if not carefully regulated.

I recently returned to my hometown to attend the Los Angeles Times Festival of Books and stayed out late a few nights for the festivities. It was my first trip home since I started amateur astronomy, so of course I looked up at the sky.

Around 10pm on my first night, I was shocked by what I saw. The horizon looked as if the sun had just set. I knew something was different, but I couldn’t understand why it felt weird at first. Then I realized it was because the horizon was a bright white, filled with the glow of her LED lights, not the orange color I grew up with. I also felt scared that I wouldn’t be able to see the stars while I was at home. In fact, I relived the almost empty night sky of my childhood.

But this time it was different. Because I understood in my head exactly what was missing. And because light pollution arrives at all frequencies, getting rid of it is easy for amateur astronomers like my friend Marvin, who says there are fewer stars today than he did five years ago. I also knew that it was impossible.

Organizations like Dark Sky International They documented how lighting acts as pollution and can affect everything from the very functioning of ecosystems to our ability to access the cultural heritage of the night sky. In a big city like LA, this may seem like a losing battle. Randy Newman, which I love, but luckily for us, that’s not true. DarkSky International actively works with communities around the world to safely install responsible, ground-focused lighting while minimizing negative impacts to communities. When we talk about environmental responsibility, the way we light our homes and streets at night should also be part of the conversation.

Want to help? Simple things you can do include installing blackout curtains in your home and making sure outdoor lights around your home have screens that focus the light onto the ground. Learn about the improvements you and your community can make to lighting, and especially educate decision-makers.

A week in Chanda

What I Am Reading

Chicano Frankenstein I really enjoyed this book by Daniel A. Olivas.

What I See

I really think so Coronation Street The writers should stop making Roy suffer so much!

What I Am Working On

Consider a new model of dark matter that involves an unusual type of photon.

Chanda Prescod Weinstein is an associate professor of physics and astronomy and core faculty member in women’s studies at the University of New Hampshire. Her most recent book is The Disordered Cosmos: A Journey into Dark Matter, Spacetime, and Dreams Deferred.