Monday marks the beginning of International Dark Sky Week, a time to highlight the value of keeping the night sky dark and to inform folks about the downsides of light pollution.
Some of the world's darkest skies are in the Big Bend region of West Texas — although in recent years, light pollution from oil and gas development has lightened them.
But according to Stephen Hummel, Dark Skies Initiative coordinator for the McDonald Observatory in Fort Davis, that trend has started to reverse thanks to energy companies adjusting their lighting systems.
Hummel spoke to the Texas Standard about the broader benefits of keeping our skies as dark as possible.
This transcript has been edited lightly for clarity:
Texas Standard: Can you give us an update on the night sky around where you are, the McDonald Observatory? How are things?
Stephen Hummel: So McDonald Observatory is fortunate to have the darkest night skies of the major observatories in the United States. And my job is essentially to try to preserve that night sky because globally, dark skies are vanishing very quickly.
Light pollution or the washing out of the night sky is getting worse at a rate of 10% per year in North America. So that's very quick. And we need to actively encourage better lighting to preserve these last places left where we can still enjoy a pristine night sky.
So what are you doing to make sure that the skies around you there remain as dark as possible?
I work with the surrounding communities, such as Fort Davis and Alpine, Marfa and other communities in the Big Bend region, on outdoor lighting practices. And this includes things, not just turning lights off, but aiming lights down on the ground, or things like using a more amber tone of light so the light doesn't scatter in the air as much like blue light does.
Is this education helping? Are there parts of the world where skies are getting darker, or is the trend pretty much going in one direction?
Yeah, so there are a few places in the world where, yes, they've been able to preserve dark skies, slow the pace, or reverse the pace.
So for our sky in particular, we had a really large increase in light pollution between 2014 and 2020, mostly to our north, mostly from oil and gas activity. But we've actually been able to work with them on lighting, and we've been able to reverse the trend, and the sky is no longer getting brighter, but actually has gotten about 20% darker in the last five years.
And it has been about steady. So it does work.
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Well, I can see clearly why this would be important for the McDonald Observatory to have a super dark night sky. And I guess for everybody else, not to dismiss the value of stargazing, but what is the value of a dark sky beyond just the ability to see constellations and the planets?
The night sky is not just something humans look at. A lot of wildlife use the night sky for navigation or are tuned into the cycles of the sun and the moon. And so introducing artificial light where it normally isn't can have tremendous impacts on ecosystems.
It can impact everything from bird migration and fireflies communicating with each other to even the growth and cycle of trees and plants. And even larger mammals like bears and even mountain lions have noted to be affected by the presence of artificial light at night.
Well, you mentioned a few of the things we can do at home — pointing lights down or making sure they have a cover, maybe changing the color of lights that you use. What else would you suggest for people at home?
Looking for lights that are dark sky-approved is one way to find good sources. Using motion detectors for security rather than leaving lights on all the time could be more effective at deterring criminals.
So there are ways to reduce light pollution without living in total darkness, right? We can be safe. We can see what we need to see without wasting the light into the sky. And so there's really easy things everyone can do.
You can learn more about those things on our website, mcdonaldobservatory.org.
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The McDonald Observatory is always a fun place to visit. Do you have anything special planned for this Dark Skies Week?
Yeah, we have a wide variety of events, not just at the observatory, but through partners around the region and during dark sky week this week. So we have talks on some of our industry efforts on Tuesday. We've got star parties going on throughout the week. That's where we have telescope viewing and guided constellation tours with a laser pointer.
We have free talks as well in some of our partner areas, such as in Marfa and Terlingua. We even have a great talk on bugs at the Fort Davis National Historic Site just down the road. So there'll be a talk and then a night hike as well.
So lots of things going on throughout the week, lots of ways to participate, and a little bit of something for every age group or every demographic.
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