Understanding How Light
Fixtures Affect Sky Glow –
And Why It Matters
Skyglow, also known as light
pollution, is the brightening of the night sky as the result of excessive and inappropriate artificial
lighting.
Photo: Light pollution is an
increasing problem threatening astronomical facilities, ecologically sensitive habitats, wildlife, and
energy use.
The Department of Energy’s Pacific Northwest National Laboratory (PNNL) wanted lighting engineers, designers, and urban planners to have more information from which to make informed lighting decisions about the factors leading to sky glow.
Photo: The Bortle Scale is a
nine-level numeric measure of the night sky’s brightness in a particular location. It quantifies the
astronomical visibility of celestial objects and the interference caused by light pollution (photo
credit to Skyglow Project).
The 2017 joint study on sky glow uncovered factors beyond color temperature that
contribute to sky glow, including atmospheric conditions and spectral power distribution (SPD). An outcome
of the study was the development of the Sky Glow Comparison Tool.
This new way of looking at factors influencing sky glow and a tool that helps
measure and compare lighting fixtures is important. Protecting dark skies and decreasing light pollution
will have positive effects on the environment and the wellbeing and health of all living things, from plants
and animals to humans.
As a holistic physician, Dr. Sara Warber, Professor Emerita, Department of Family
Medicine, at University of Michigan, has a strong interest in human wellbeing.
Dr. Warber's understanding of the connection between nature and physical and emotional wellbeing comes from
her experience growing up. "I was happiest when I was outside," she explains.
"And that is still true. Humans are rejuvenated by being outside."
Dr. Warber is interested in the full range of outdoor experiences, nighttime
included. "Viewing the night sky is awe-inspiring and humbling. I am a little speck
in this huge unfolding place. Being humbled, in this sense, feels good and increases my wellbeing. I feel
connected to this huge place but also small. I can let go of my small preoccupations in the midst of
this immense world.
Photo: Light pollution is an
increasing problem threatening astronomical facilities, ecologically sensitive habitats, wildfire, and
energy use.
"One of the problems with overly lit nights is that they block humans from the
broader experience of the darkened environment," Dr. Warber continues. "But people need to feel safe in
order to have an increased sense of wellbeing. LED technology is an incredible boon to people and our need
for light. LED light can be environmentally manipulated. We can be more selective about the brightness,
color, and purpose of that light-and expose people to nature 24 hours a day."