Canis Major, a constellation of the winter sky. Sirius, the brightest star in the sky, is in this constellation. Canis Major rises in the east after Orion, the hunter. It is slightly below Orion, and appears near the southern horizon in the United States. A line through the three bright stars of Orion's belt leads to Sirius. In classical mythology, Canis Major (great dog) was one of the hunting dogs of Orion, and the constellation is supposed to look like a dog.
The changing phases of the moon have given us an enduring curiosity about the dark side of the moon. But is there really a dark side of the moon? What would we see there?
We can't defy the odds of an asteroid taking a turn for Earth forever, so the world's astronomers watch the sky. What happens once they spot something?