As a sun-like star like Sirius evolves, it switches fuels in its core and bloats into a red giant. The giant then expels its outer atmosphere, forming a colorful planetary nebula that expands away ...

These hot August nights can be great for stargazing. Here’s a look at what’s going on above us right now and later in the month. The expression “dog days” refers to the period from July 3 through Aug.

Sirius, also called the Dog Star, is the brightest star in Earth's night sky. Shining more brilliantly than any other star visible from Earth (excluding our sun, of course), Sirius is outshone only by ...