Cygnus, a constellation that lies in the Milky Way between Lyra and Pegasus. It contains the first-magnitude star Deneb. Deneb and four other stars within the constellation form the Northern Cross. Cygnus is named for a character in Greek mythology who was turned into a swan and placed in the heavens by the god Apollo.
It wasn't so long ago that astronomers thought the universe contained normal matter, or baryonic matter, the base unit of which is the atom. But when it comes to the cosmos, there's always more than meets the eye. What else is hanging out in space?
The sun warms our planet every day, provides the light by which we see and is necessary for life on Earth. But what is it exactly, and what will happen when it burns itself out?