January: The Process and Nature of Science February: Evolution March: Physics and Technology April: Energy Resources May: Sustainability and the Environment June: Ocean and Water July: Astronomy August: Weather and Climate September: Biodiversity and Conservation October: Geosciences and Planet Earth November: Chemistry December: Science and Health Year of Science 2009 home page
Cassiopeia

This composite image from three space telescopes shows a debris cloud called Cassiopeia A. The 15-light-year-wide cloud was formed when a star exploded 325 years ago, leaving a trail of gas (blue, green, and yellow) surrounded by a shell of interstellar space dust (red).
Photograph courtesy NASA/JPL/Caltech/Oliver Krause, University of Arizona.