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Ghostcatching

Emily Coates and Sarah Demers

Physics and dance share the singular problem of our universe: time moves in one direction. Events that occur can never be repeated exactly. A detector captures the collision of two black holes as an abnormal frequency—a cosmic blip, like the notation for a billion-year-old dance. A similar challenge comes from trying to re-create the dancing of Master Juba, a virtuosic African American dancer of the 1840s, through the writing and testimonies of those who saw him perform. Dance historians reconstruct events through their traces in the archive, just as physicists do when they interpret data from detectors. The reverberations of a past event may be felt today, but the event will never (indeed can never) occur again in the same exact form.

No moving image of Master Juba exists. But starting with the rise of film and then video in the twentieth century, the great dancers have been captured on screen—at least, those fortunate enough to be filmed. A collection of moving image technologies has emerged over the past one hundred and twenty-five years that has helped scholars to augment the dance archive: from film and video to smartphones and motion-capture laboratories, these introduce the ability to freeze, rewind, jump-cut, and slow down time to excruciating extremes. They can even record the essence of human movement, devoid of the human body.

Motion capture, a more recent computer technology, generates another kind of dance replication: an image that is not two-dimensional but three. Such a system produced Ghostcatching, a seminal work of digital art created collaboratively in 1999 by Paul Kaiser, Shelley Eshkar, and the dancer choreographer Bill T. Jones. Motion-capture systems track sensors placed on the human body. With the data from each sensor, the computer assembles a visual representation of the movement that can then be applied in a number of disciplines, from medicine to digital animation and other works of art. Over a number of research sessions, Jones was suited up with sensors and then improvised various dance movements. Together, Jones, Kaiser and Eshkar refined the phrases, which Kaiser and Eshkar edited and treated with hand-drawn lines. The figural images that appear in the final video proliferate and recombine. The background is black and abstract, not the real world, with lyrical lines that both form Jones’s figures and create layers, like a sediment through which he moves.

Ghostcatching unquestionably experiments with space, but the formal play with time most speaks to our purposes here. The video begins with what Kaiser has called an “ancestral figure,” the creator who spawns all the other dancers that appear, all of whom are hand-drawn versions of Jones.60 The movement phrases have been cut up and remixed from Jones’s live improvisation. Through digital art, the creators craft altogether new characters and a new narrative.

Many dance writers, including Jones, have noted the absence of sweat in Ghostcatching. Motion capture, as Jones has observed, takes away dance’s hard-won ephemerality.61 The system turns movement into a series of data points that describe location and speed. But there is something missing in what the technology records, too. The figures hop, stretch, and crawl under alien physical conditions—their actions are too light, too buoyant. Theirs are not bodies on earth, but bodies in digital ether. Kaiser and Eshkar were concerned with intermedia translation and drawing, more so than with preserving Jones’s exact performance. Their digitally rendered line drawings create a compelling new art while losing what the dance scholar Ann Dils has described as Jones’s “animus”—his life force.62

Only in the sound do you feel his animus. Jones hums, narrates fragments of stories, and sings children’s songs that evoke spirituals. The recordings capture the physics of sound on earth: Jones’s vocal folds vibrate, and that vibration pushes the air out into high and low-density patterns that carry through the air on sound waves. His vocalizations contain the human quality missing in the moving image. Jones’s voice is the true ghost of Ghostcatching, as opposed to the traces of his motion that end up on the screen, because something more familiar to lived experience registers—something more true to the human body in its engagement with physical forces. Complicating the digitization, the earthly physics expresses the African American history and identity that Jones never leaves far behind. Take away that physics, and not only Jones’s animus but also human history itself appears to evaporate.

Consider the gap between an event and its record as a kind of ghostcatching: what is imprinted in the archive, and what is left behind? What “animus” do scientists miss, on a much vaster scale, when they read data on the motions of planets and stars that occurred billions of years ago? How can we think about liveness and life force as bridges between humanistic and scientific inquiry?

What other kinds of questions should we be asking?

The Story of the Universe

Artists can tell stories, thereby shaping time. But how do we craft the story of the universe? Was there a beginning and will there be an end, or are we in the midst of a cycle that has always been repeating and will repeat for all time?

In physics, the current view of the universe is that it began with a bang almost 14 billion years ago. Scientists do not know the origin of the bang, and they do not know if it was the first bang that ever happened. More broadly, they also do not know whether humans inhabit the only universe that has ever existed, or even if other universes currently exist. Strong evidence leads scientists to believe that the earth is approximately 4.5 billion years old and that it will be engulfed by the sun within a few billion more years. (That leaves plenty of time for humanity to figure out intergalactic travel if we manage to continue scientific exploration.) As we reported in Chapter 7, scientists have evidence that our universe is expanding at an accelerating rate, which means that if there is an end to the universe, it will probably be cold and dark and difficult to define.

We can peer back in time by looking at objects farther and farther away from us. When we look up in the sky and see the moon, we are not seeing the moon as it exists now—we are seeing an image a little over a second old. It takes that much time for reflected light leaving the surface of the moon to reach our eyes on earth. The image of the sun we see in the sky is eight minutes old. The sun is farther from us than the moon, so it takes an additional amount of time for its light to reach our eyes. The North Star, Polaris, is several hundred light years away from us; the image of the star that we see at night is several hundred years old. If we look farther out into space, we are peering even farther back in time. Assuming that we can account for disruptions in the light as it travels to us, we can watch the history of our universe unfold. And modern telescopes are certainly much more sensitive than human eyes. Some of our instruments allow us to access light that set off on its journey toward us billions of years ago.

Our understanding of the life cycle of the universe continues to evolve as our tools mature, and the story is certainly not over.

From Physics and Dance by Emily Coates and Sarah Demers. Published by Yale University Press in 2019. Reproduced with permission.


Emily Coates is associate professor in the theater studies program at Yale University, where she created the dance studies curriculum. 

Sarah Demers is Horace D. Taft Associate Professor of Physics at Yale University. Their work has been featured in the World Science Festival and covered in the New York Times and the New Yorker.


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Featured photo by Ahmad Odeh on Unsplash

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