The collision of two supermassive black holes is the most violent event that can occur in the universe; experts explore where a black hole's energy originates and what really happens when the two most powerful objects in the cosmos clash. It is a soul-chilling, mind-crushing amount of energy. Take your ringside seat to the ultimate fight of the universe. Get ready for the final of the cosmos heavyweight championship.

November 4, 2029. We face a countdown to catastrophe. A giant asteroid hurtles towards Earth at 40,000 mph. It's heading straight for the eastern seaboard of the United States. The space rock could wipe out an entire city and cause widespread devastation. Can Earth survive? Now, experts confront the story of this fictional asteroid event to determine what could happen, and how it might be stopped.

New discoveries have rewritten the history of our solar system, revealing a complex and violent story that begins with the birth of our Sun from the debris of a massive galactic collision, to its eventual fate as a lone zombie star.
It is a dramatic history of elegant beauty and extreme violence. The inner solar system was like a congested highway. Planets crossing lanes, frequent collisions. There were a lot of planets that could have made it but didn't, and we just happen to be one of the lucky ones that did. The players in our solar system's story are more tangled up than we ever imagined. Without all of these things interplaying, the Earth wouldn't have the stable environment that we have today, and life wouldn't be able to exist.

As summer spreads across our planet, honey bees toil, snow geese breed, tadpoles awaken and lions stalk wildebeest in search of lush grass.
Our planet is solar-powered. But due to the Earth's tilt, it doesn't strike its surface evenly. This solar energy arrives in varying amounts at different times of the year. The huge increase that comes with summer also triggers countless migrations.

Some animals give their young the best start in life by making truly astonishing journeys. And it's not only where they go that's important but when. Left to fend for themselves until they find their footing, baby sea turtles, elephant seal pups, pumas and crabs bravely trek towards adolescence.

For many animals, the instinct to move is overwhelming, despite the dangers. But for every trip that ends in tragedy, countless millions reach their destination. Allowing them to reap the rewards of better conditions and fresh opportunities. However, we have now changed the planet. Cutting off ancestral routes and impacting even the most remote corners of the globe. But there is hope. We know more about these journeys than ever before. And with our help, many animals are now overcoming the challenges of our modern world. For a healthy and connected planet, we must preserve the freedom to move.