Director of Conservation, Stewardship and Research, Presidio Trust
Terri Thomas manages the Presidio's natural resources programs, which includes plants and wildlife, of course, but also the natural quiet and dark of the night sky. The Bay Area native spent the summers of her youth at a cabin in the Sierra, which she credits with making her feel at home in nature. For the past three decades, she has made it her mission to bring that experience into urban areas, connecting people in cities to the natural resources in their own backyard. The Presidio sat down to discuss the recent Presidio Stargazing Party, and how the stars and light affect the Presidio's natural habitat.
The next Presidio Stargazing Parties are December 19, 2015 and February 13, 2016.
Why is "night sky" important?
The sky that we see tonight is the same sky that people have been looking at for thousands of years. You're seeing the same stars that Edison saw, or Ben Franklin, or Native Americans. You're also seeing the same sky as people see on the other side of the world. So when you look up, you're breaking through that space-time barrier. It connects us.
It's also inspirational. Think about the myths, the religions, the art and music that have been inspired by the stars. There's a quote: "It is indeed a feeble light that reaches us from the starry sky, but what would human thought have achieved if we could not have seen the stars" (Jean Perrin). I tingle when I say these words, but I think that's what's important about the dark night sky.
The dark night sky is also critical to so much of nature. For example, migratory birds use the starlight to navigate their migration. So when there is light in another area, sometimes they can get disoriented, because they have evolved with the dark night sky.
How does a dark night sky benefit wildlife in the Presidio?
Humans are diurnal creatures. We feel most comfortable in the daytime. So it's only natural for us to want to put lights everywhere. But almost half of the wildlife in the world is nocturnal, and darkness is essential to their habitat. In the Presidio, and all over the world, light affects animals' mating, foraging and sleep. We think of owls and bats as nocturnal, but foxes, skunks, and raccoons come out at night as well. If you go out at night in the Presidio, you'll see a whole different type of wildlife.
What we've been talking about doing in the Presidio is having some areas where we allow the natural darkness to occur. We focus light where people are walking or getting to their cars, and not up into the air where it's wasted.
And for humans, how does the night sky increase our enjoyment of the Presidio?
As Vincent Van Gogh said, "I often think that night is more alive and more richly colored than the day." I think that can be true if we allow ourselves to feel comfortable with the darkness. That's part of why we're having these stargazing events – so people can see that darkness is valuable for humans, as well.
We also want to maintain the historic setting as much as possible so that people can relive history, and the dark night sky is part of the historic landscape. You're seeing the same night sky as the people who founded the place, and the Native Americans before that. But they wouldn't have had lights. For Native Americans, it would've been more like what I see in the Sierra. It's so spectacular to see a huge dark night sky, and it isn't impossible here in the Presidio, as more people begin shielding their lights and being careful about how they use light.
What would you like people to get out of these Presidio stargazing parties?
When you're learning about the stars and the galaxies and the planets, you get much more excited about them if you can actually see them. You don't get the same feeling in a planetarium as you do when you're looking through a telescope and the star or planet is right there, and someone is there to tell you the stories and the myths, and explain what the stars are, what they're made of, how far they are from Earth.
Also, I'd like to see people inspired by the questions that the stars and planets provoke, along with the timelessness and spacelessness of the universe. Life in the city can feel so controlled, and then you look up there and there's no control. It's just… wow.
Photo by Charity Vargas Photography