Pluto's moon an ice machine

July 22, 2007

Frigid geysers spewing material up through cracks in the crust of Pluto’s companion Charon could be making this distant world into the equivalent of an outer solar system ice machine.

“There are a number of mechanisms that could explain the presence of crystalline water ice on the surface of Charon,” said Jason Cook, a doctoral student in the School of Earth and Space Exploration at Arizona State University who led a team of planetary scientists studying the surface of Charon. “Our spectra point consistently to cryovolcanism, which brings liquid water to the surface, where it freezes into ice crystals. That implies that Charon’s interior possesses liquid water.”

To reach this conclusion, Cook and his collaborators studied a number of other mechanisms that could explain the presence of water ice crystals on Charon. The only mechanism that explained the data was cryovolcanism, the eruption of liquids and gases in an ultra-cold environment.

Cryovolcanism in the outer solar system is a fairly common occurrence. Enceladus (a moon of Saturn) and Europa (orbiting Jupiter) both show evidence of water ice oozing or spewing out from beneath the surfaces.

Evidence for the ice deposits came from high-resolution spectra obtained using the Hawaii-based Gemini Observatory’s Adaptive Optics system, ALTAIR coupled with the near-infrared instrument NIRI. The observations, made with the Frederick C. Gillett Gemini North telescope on Hawaii’s Mauna Kea, show the fingerprints of ammonia hydrates and water crystals spread in patches across Charon.

This discovery could have profound implications for other similar-type worlds in the Kuiper Belt – the region of the solar system that extends out beyond the orbit of Neptune and contains a number of small bodies, the largest of which include Pluto and Charon.

The team’s intent was to find evidence of methane, carbon dioxide, ammonia, and a form of ammonia called ammonia hydrate on the surface of Charon, which has also been reported on Quaoar and suspected on at least one other Kuiper Belt Object.

According to ASU assistant professor Steven Desch, Cook’s colleague and thesis advisor, ammonia hydrates help keep liquid water from freezing solid, making it easier for water to escape from the inside before it turns to ice. “It is literally an antifreeze,” he said, “and like the antifreeze we’re familiar with here on Earth, it depresses the melting point of water.”

Cook and his colleagues concentrated their observations on Charon’s anti-Pluto and sub-Pluto hemispheres. Their findings were published in the paper “Near-infrared Spectroscopy of Charon: Possible Evidence for Cryovolcanism on Kuiper Belt Objects” in volume 663 of The Astrophysical Journal. In addition to Cook and Desch, the team included Ted L. Roush (NASA Ames Research Center), and Chad Trujillo and Tom Geballe (Gemini Observatory). Additional information and images are on the Gemini Observatory’s Web site at:">"> Download Full Image

Robert Burnham

Science writer, School of Earth and Space Exploration


Creative writing professor co-hosts nature-inspired exhibit

July 22, 2007

Artist Lisa Marie Sipe and poet Patricia Murphy have both found inspiration from their explorations of Arizona’s wild areas. This common theme in their paintings and poetry inspired them to collaborate on a project that represents sensory images from the natural world in a display of art and text. The collaborative exhibition will be featured at Eye Lounge Gallery in Phoenix from July 6 to July 28.

We started this project with a discussion of the different ways that poetry and paintings offer representations of the natural world,” says Murphy. “We wanted to turn those notions upside down; to allow people to experience the text as art and the art as text.” Their innovative exhibit challenges traditional notions of text and paintings by changing the way the two are displayed. Download Full Image

Sipe adds, “Once we decided how we wanted to display our work, we talked about how to create it. We wanted to experience nature together, but as individual artists. We took a trip to an Arizona trail neither of us had visited before, and we explored it together, interpreting it as one poet and one painter. This exhibit is about the two of us as artists: how we interpret the experience, how the experience is enriched by sharing it with another vision. We asked ourselves, are we drawn to different details? Do a poet and a painter see the world differently?”
Murphy continues, “The purpose of the collaboration was to explore and identify skills we use to communicate and capture experience. The outcome was that we grew as artists, we reflected on our relationships with craft, we shared an opportunity to interact with our individual art forms.”

Lisa Marie Sipe is an acrylic and encaustic painter based in Arizona. Her work is influenced by the inspiration she finds from her travels and the Sonoran desert around her. She explores the fingerprint of nature, pushing the boundaries of beauty. Sipe's work has been described as “abstract botanical.” Previous work includes large paintings of wood texture as seen through a microscope. Her new work maintains that organic feel.

Patricia Murphy’s poetry explores the intersections of culture and capitalism in the desert southwest. Her poems about the Sonoran landscape have appeared in over 20 literary journals, including The Iowa Review, Quarterly West, and American Poetry Review. She teaches Creative writing at ASU at the Polytechnic campus.

The show “Fossil Springs Cutaway” is named for the area in central Arizona that Murphy and Sipe explored, and a term from film that describes the technique of interrupting action by interjecting an alternative view. The collaborative exhibition will be featured at Eye Lounge Gallery in Phoenix from July 6-July 28th, with the First Fridays opening on Friday July 6th, and with a reception and reading on July 20th.

Gary Campbell

Media Relations and Marketing Manager , Fulton Schools of Engineering