For a while I thought my career and my personal life were fairly separate, but lately I’ve realized there’s more overlap than I thought. I have been interested in both photography and astronomy for most of my life. I ended up pursuing astronomy as a career, but never stopped taking pictures. And most recently I have been photographing the night sky more, especially as a background to dramatic landscapes in dark sites such as national parks. Much of my career has been spent producing images from Hubble Space Telescope data. There’s the obvious connection, that it’s all related to photography. I suppose one of the reasons I was originally drawn to astronomy as a career was that it was so intimately associated with photography. But lately I have been considering the possibility of deeper connections.
Familiar landscape photography can be described as “representational,” that is the image captures the reality of the scene in a more or less faithful representation. At first, images of deep space may appear to be abstract, with no easily recognizable subject. But with some understanding of the subject, the images transform and take on a greater depth. The photographs of deep space from Hubble and other telescopes are entirely representational: real photographs of real scenes, albeit made with very specialized technology.
It may not seem obvious, but there are actually some things in common between familiar views of terrestrial landscapes and deep space besides coincidental similarity in form or color. But there are much deeper similarities in the physical processes creating these landscapes, even though the scales of physical size and the materials are vastly different. Here are a few examples.
In the first pair of images there is a reddish foreground and a blue star-lit sky background. In the Earthbound landscape photograph is a ridge of rust red, iron-rich rock in Zion National Park, lit by the moon with trails of stars in the night sky. The sky is blue due to the Earth’s atmosphere. In the companion image from Hubble, the ridge is gas and cosmic dust spread over volumes of space light-years across. The mostly hydrogen gas is glowing red. The blue, star-filled sky behind is also gas but at at different temperature, mostly oxygen glowing blue. In the photo from Zion, the camera was fixed on a tripod. As the Earth turned during the long exposure the stars moved across the sky and left bright trails. In the Hubble image, the telescope tracked the stars so everything remained sharp during the long exposures.
These images both show erosion processes in action. The prominent rock in the Earthbound image is 18 meters (60 feet) of rusty red sandstone known as Delicate Arch in Arches National Park, Utah, silhouetted against the Sun. Water and wind have eroded away more fragile rock to expose the more resistant rock of the arch. In the Hubble image are pillars of gas and dust spanning light-years in the Eagle Nebula in our Milky Way galaxy. Strong radiation and winds from extremely hot, luminous stars have removed the less dense gas and dust and left the denser material. The dusty pillars are silhouetted against the brighter light from the surrounding nebula.
We are looking at a galaxy in both of these photographs. In the terrestrial landscape, the galaxy is our own Milky Way. We live in one of its spiral arms and looking toward the brighter center of the galaxy, on the right end of the Milky Way arch. All the stars we see in the sky, the dark lanes and bright nebulas in the Milky Way are all part of our galaxy. Below the Milky Way is Mesa Arch in Canyonlands National Park, Utah. In the Hubble image we see the barred spiral galaxy known as NGC 13001. It is the prototypical example of this class of galaxies, known for the straight bar from whose ends the spiral arms originate. This is what astronomers think our Milky Way galaxy might look like if we could fly far away from it and look back toward home. So in both photographs we are looking at similar structures at similar scales. From Earth we are looking at a galaxy from inside it, with Hubble we can see vast numbers of galaxies in the universe.
These two photos show visually related phenomena but with vastly different physical scales. The Earthbound photo is Castle Geyser in Yellowstone National Park, Wyoming. Water and steam heated and pressurized by hot rock deep underground escape with great force from a narrow opening at the surface, blocking out the sun behind. The Hubble deep space photo shows a planetary nebula known as NGC 6302, about 3,400 light-years away in the Milky Way. Gas and dust has been ejected from the outer layers of a star after it exhausted much of its hydrogen gas fuel. The very hot, bright remnant star is energizing the various components of the gas making it glow in different colors. A disk of gas and dust near the center is dense enough to block the light of the star deep within but also to force the material escaping from the star to be directed into the symmetrical hourglass shape.
This sampling highlights to me how everything in the universe is connected. We stand on the Earth, a ball of rock orbiting an average star, and marvel at grand, powerful landscapes that seem vast relative to our human scale. At night we can look up at the sky and marvel at the vast array of stars, the Milky Way, or the dance of the planets in a celestial landscape. Using powerful instruments we can peer across the vast depths of the cosmos to view incredible places, unimaginably large and unimaginably distant compared to our terrestrial perspective. These are all parts of nature that we can appreciate thanks to the power of our senses and the instruments built by generations of very clever people to extend the reach of our sight and make sense of what we see. We now know that these faint sources of light in the sky, no matter how distant and seemingly alien, are all real places and all part of our common natural environment.