... Liftoff With the Space Shuttle . ... M31: The Andromeda Galaxy . ... The diffuse light from Andromeda is caused by the hundreds of billions of stars that compose it. ... At the Center of the Milk Way . ... Almost lost in this cosmic jumble of stars, gas and dust is a faint but definite blue arc -- a stream of young stars whose formation was probably triggered as a small dwarf galaxy was torn apart approaching the giant elliptical galaxy Centaurus A. Oklo: Ancient African Nuclear Reactors . ...