Antares, the brightest star in the constellation Scorpius. The star has a red color like that of the planet Mars. This color is due to the star's relatively low surface temperature (about 5,500 F. [3,040 C], as compared to 11,000 F. [6,100 C] for the sun's surface). Antares was named for its color; it means "rival of Mars" (Ares is the Greek name for Mars). Antares is about 520 light-years from the earth. Its brightness is due to its large sizeit is about 350,000,000 miles (560,000,000 km) in diameter. It is one of the largest stars known and belongs to a class of stars called supergiants. It is a variable star, with a magnitude of 0.92 at maximum brightness. Antares has a much hotter, smaller, faint blue companion star.
When you think about massive, mysterious cosmic bodies like accretion disks, the water swirling around your bathtub probably isn't the first thing to come to mind. But hey, physics works the same magic on all scales.
Sunspots are peculiar dark areas that show up regularly on the surface of the sun -- and often for no reason. What causes them? What effect could these funny little spots have on the Earth?