Do other rich planetary systems exist? Our Solar System has the most planets of any known star, most probably because it is so hard to detect planets around other stars. Sensitive measurements, though, have...

From left to right are the enclosures of Yepun (ye-poon; Sirius), Antu (an-too; Sun), Kueyen (qua-yen; Moon), and Melipal (me-li-pal; Southern Cross), pictured here as night falls at Paranal Observatory in northern Chile. These are the four 8.2 meter wide telescope units of the European Southern Observatory's Very Large Telescope (VLT).

How did spiral galaxy ESO510-13 get bent out-of-shape? The disks of many spirals are thin and flat, but not solid. Spiral disks are loose conglomerations of billions of stars and diffuse gas all gravitationally orbiting a galaxy center.