... The entire sky is seen projected on a coordinate system centered on our Milky Way Galaxy with the plane of the Galaxy running across the middle of the picture. ... Alpha Centauri: The Closest Star System . ... The closest star system to the Sun is the Alpha Centauri system. Of the three stars in the system, the dimmest -- called Proxima Centauri -- is actually the nearest star. ... In the center of 30 Doradus lies a huge cluster of the largest, hottest, most massive stars known. ... The Iron Sun . ...