Scorched by their proximity to the sun, Mercury and Venus are hostile worlds; one gouged with craters from cosmic collisions and the other a vortex of sulfur, carbon dioxide, and acid rain.

They are breathtaking, lethal, and a constant source of surprise. The stunning rings of Saturn have mesmerized countless scientists over the centuries.

Ours is a universe of energy, from powerful jets ejected from black holes to the raw nuclear fury of our Sun. But, the total amount of energy in the universe maintains perfect equilibrium--no more can be added or taken away.

A stellar explosion, the supernova is the sensational death of a star. It can shine as bright as 100 billion Suns and radiate as much energy as the Sun would emit over 10 billion years.

Take a tour through the "Art Gallery of the Galaxy" and view what are considered the "crown jewels" of the heavens. Nebulas are mysterious clouds of gas that aren't classified as stars, planets, moons, or asteroids.

They are the one-stop-shopping places for learning all about the nature and variety of stars in the Universe. They're unique, because in clusters, all the stars were born at about the same time.

They sort of sound like the same phenomenon, but Pulsars and Quasars are very different. Pulsars are tiny--only a few miles across--but they spin as fast as a kitchen blender and sweep the sky with beacons of radiation that make them appear to flash.

There really are ice worlds like Hoth from Star Wars. In this episode, we explore icy planets and moons, discover the role of cold in the Universe, and learn about the importance of ice to the development of habitable worlds.