Dusting Spiral Galaxies . ... Credit Copyright: W. Keel and R. White ( U. Alabama ), NASA Explanation: How much dust is in spiral galaxies? ... This striking, detailed Hubble Space Telescope image of dust in the outer reaches of a foreground spiral galaxy (left) back lit by an elliptical galaxy offers an elegant approach to providing the answers . As expected, dust lanes in the foreground galaxy seem to be associated with spiral arms. ... NASA Web Site Statements, Warnings, and Disclaimers . ...