Thursday, September 17, 2009

Look on Dark Asteroids

The main feature of the dark asteroids is that they remain dark emitting very little light and so they are able to move in shadows between bright places. scientists are building by far the most sensitive set of wide-angle infrared goggles ever, a space telescope called the Wide-field Infrared Survey Explorer, or WISE.

WISE will scan the entire sky at infrared wavelengths, creating the most comprehensive catalog yet of dark and dim objects in the cosmos: vast dust clouds, brown dwarf stars, asteroids -- even large, nearby asteroids that might pose a threat to Earth. Surveys of nearby asteroids based on visible-light telescopes could be skewed toward asteroids with more-reflective surfaces. If there's a significant population of asteroids nearby that are very dark, they will have been missed by these previous surveys.

The full-sky infrared map produced by WISE will reveal even these darker asteroids, mapping the locations and sizes of roughly 200,000 asteroids and giving scientists a clearer idea of how many large and potentially dangerous asteroids are nearby. WISE will also help answer questions about the formation of stars and the evolution and structure of galaxies, including our own Milky Way galaxy.