Astronomical Synesthesia


Radio image of the Crab Nebula: an example of astronomical information that can be neither seen nor heard directly

The image to the left is a radio picture of the Crab Nebula, the debris field from a massive supernova explosion that was recorded by astronomers in 1054 AD. These data come from 11 hours of observations made by a large array of metal dishes called, uncreatively, the Very Large Array. In this image, we see the structure of the debris as it streams away from the explosion site at 1000 kilometers per second, energized by radiation and winds coming from the remnant of the long-dead star, a spinning ball of neutrons 10 km wide and more massive than our Sun.

Except, we don’t actually see anything.

What I mean is that our eyes cannot possibly register an image like this. The radio light collected by the Very Large Array has wavelengths of 6 cm – about the length of your little toe – and our eyes are simply too small to receive that kind of light. And before you think of listening to the Crab, remember that radio waves are a form of light, not sound. The information you see above cannot been seen, heard, touched, tasted or smelled. It is outside the human experience.

Astronomers regularly deal with information beyond our human senses through telescopes and instruments that are built to extend our senses, extracting data from the Universe that would otherwise go unnoticed. To understand, interpret and manipulate that data, we must then convert that data into a form our senses can handle. The radio image of the Crab Nebula is a false-color image; the invisible radio light has been converted into a map of visual light through a defined transformation. Through this intermediary step, we are able to experience information about the Universe that would otherwise be lost.

Visual mapping is not the only transformation one can imagine. Fiorella Terenzi, a former research scientist at UCSD, became famous in the early 1990s for converting radio maps of galaxies into sound (and thus began a flourishing music career). There are also “recordings” of Sun’s interior oscillations, even though

  1. sound does not travel through space;
  2. we have no microphones in, on or near the Sun; and
  3. the Sun’s oscillations are too low in frequency for our ears to pick up anyways.

Such auditory transformations can nevertheless be useful in picking out subtle patterns that might be missed in visual images. Recall the scene in the movie Contact when Jodie Foster pipes the radio transmissions of an extraterrestrial intelligence (detected with the Very Large Array!) into speakers to try to pick up the underlying structure. ET phoned us!

Transformations of astronomical data can also produce aesthetically striking work as well. Consider the image of Saturn below from the Astronomy Picture of the Day site:


Saturn as imaged by Cassini

This image was created by a camera on board the spacecraft Cassini, which is currently orbiting the ringed world and sending back gobs of amazing photos. This photo in particular combines visible light we can see (the yellow-green haze to the lower left, a reflection of sunlight on the clouds) and invisible infrared light we can’t (the mottled red pattern along the top of the planet). As an astronomer, this false-color image tells me a lot about the internal composition of Saturn and its atmospheric dynamics. But as a art-appreciating human, this image is simply beautiful.

One of the primary objectives of Project Planeteria is to explore the transformations we use to analyze astronomical data that cannot be directly experienced, and reimagine these transformations into modalities of the human experience – physical, emotional, social – as well as multi-sensory interaction – light and sound, heat and texture, etc. In the latter case, we are exploring a kind of astronomical synesthesia, allowing other senses to chew on what has been the realm of the visual, and seeing where these transsensory and multimodal experiences take us.

Stay tuned for more!

Image credits:

Crab nebula: NRAO/AUI and M. Bietenholz:
Saturn: VIMS Team, U. Arizona, ESA, NASA:

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