EYE IN THE SKY A stellar nursery 20,000 light-years from Earth known as Westerlund 2 showcases the Hubble Space Telescope’s sharp vision in an image taken in honor of the observatory’s 25th anniversary.
NASA, ESA, S. Perlmutter/LBNL/UC Berkeley, A. Koekemoer/STScI, M. Postman/STScI, A. Riess/JHU, J. Nordin/LBNL/UC Berkeley, D. Rubin/Florida StateUniv., C. McCully/Rutgers Univ.
GALACTIC SMASH-UP The many galaxies of the cluster Abell 3827 appear in this Hubble Space Telescope photograph. The center of the cluster contains four colliding galaxies (yellow blobs). The bluish circle around the galaxies is the light from a more distant galaxy bending around the cluster’s center due to gravity from both stars and dark matter.
WHERE THE MATTER LIES This new map of dark matter covers an area about 700 times as large as the full moon as viewed from Earth’s surface. Areas with relatively little dark matter are blue; regions with a lot are yellow and red. The gray dots indicate the locations of known galaxy clusters, with the size of the circle representing the cluster’s mass.