Hubble Space Telescope Finds Kuiper Belt of Many Colors

The sun isn't breed to objects without atmospheres. Bombarded by solar radiation, the surfaces of some comets for instance, tend to be a burnt carbon-black. But the 1,000 objects so far directly imaged in the Kuiper Belt that swath of icy bodies circling around the sun with Pluto emerge to be a wide range of colors: red, blue, and white.

With slight observations to go on – most of the Kuiper belt objects are just a single pixel of light to the Hubble Space Telescope – few hypotheses have been developed to elucidate the colors. But a new computer model maps out the right combination of materials and space environment that could create some of those lovely hues. The model suggests that these objects have many layers, and that the red colors of one particularly interesting group of these objects, the so-called Cold Classical Kuiper Belt -- could come from organic materials in the layer just under the crust.

"This multi-layer model provides an additional flexible approach to understanding the diversity of colors," says John Cooper, a Heliospheric physicist at NASA's Goddard Space Flight Center in Greenbelt, Md. "The model calculates the rate at which energy comes in from radiation and could be causing changes at different depths. So we can define different layers based on that."