For most, it's the deadly centerpiece of the film Star Wars. But in truth, real death stars are in the final stage of life before they explode into supernovae and, occasionally, the biggest blast in the universe--the gamma ray burst (GRB).

The many benefits of the earth's large moon are explained and the consequences if we did not have a moon.

Every year, thousands of objects both natural and manmade plummet through our atmosphere and crash into the Earth. These menacing messengers from the sky provide scientists with amazing insights into the natural, and not so natural, phenomena. Written by Anonymous

The Universe is full of explosions that both create and destroy. The Chicxulub impact on the Yucatan peninsula, which may have wiped out the dinosaurs 65 million years ago, was two million times more powerful than the largest nuclear bomb ever detonated. Written by Anonymous

This program traces the history of the discoveries of planetary rings. The composition and the physics of the formation and stabilization of rings are explained.

Scientists discuss 10 different ways of destroying the Earth; including Venus to Earth impact, the Big Burn, Stop the Spin, Black Holes, Turn off the Gravity, Anti-Matter Annihilation, Parallel Worlds Collide.

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.

Scientist speculate on future space weaponry and battle tactics.

On alien planets, they rain from the sky as scalding iron. On distant moons, even at hundreds of degrees below zero, they slosh around in pristine lakes of methane. They can cover entire planets in miles-deep oceans of electrified hydrogen metal. Written by Anonymous

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.

Is science-fiction rooted in science? Has science caught up to science-fiction, past and present? Is there any scientific technology that has surpassed science-fiction? This episode explores these questions and more.

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.