For decades, astronomers have been talking about of galaxies with supermassive black holes at their cores. Now they say they've clearly confirmed a black hole's encircling, dusty, spinning disk of gas.
View larger. | The yellow lines define the near side of the moon, and the space between the yellow and green lines outline the far side of the moon that's visible from Earth, given favorable lunar librations, like the one tonight.
Sirius, the sky's brightest star, is sometimes called the Dog Star because it's in the constellation Canis Major, the Greater Dog. In this Chinese Year of the Dog ... a photo from Hong Kong by Matthew Chin.
