... Rhea: Saturns Second Largest Moon . ... Imaged by the orbiting Mars Global Surveyor's wide angle camera, the area covered is 105 kilometers across with the expected landing ellipse superposed. ... Massive stars -- upwards of tens of times the mass of the Sun - profoundly affect their galactic environment. Churning and mixing the clouds of gas and dust between the stars, they leave their mark on the compositions and locations of future generations of stars and star systems. ... Runaway Star . ...