Earth's history is marked by one cosmic disaster after another, forging the path of human evolution. Asteroid and comet collisions, flares from the Sun, mass extinctions, supernova explosions, cosmic ray bombardment. You name it, we've experienced it. It's kind of a miracle we're here at all. Now, experts explore how the Earth has teetered on the verge of destruction.

Nathan stages a ninth birthday party for Adam, but faces a problem when Remy, one of the child actors who played Adam at age six, becomes attached to Nathan, calling him 'daddy' even after his scenes are over. Remy's mother explains that her son might have trouble understanding the difference between acting and reality. To discover what went wrong, Nathan repeats Remy's scenes with different actors including Liam (a nine-year-old Adam actor), an adult actor, and a mannequin. He then explores what might have happened if Angela had stayed with him and meets with the real Angela, who urges him to forgive himself, as her religious beliefs state.
In an attempt to truly understand the connection between parent and child, Nathan stages a new scenario in which he is Remy's mother Amber and Liam portrays Remy. They re-create the experience of appearing on The Rehearsal and becoming attached to 'pretend daddy' Nathan. After coming to the emotional realization that they should not have done the show, Nathan as Amber seemingly breaks character and tells the fake Remy, 'I'm your daddy.'

In the second episode, the murder of a political staffer in 2016 spawns a myriad of unfounded conspiracy theories as the man's family and the truth hang in the balance.
Following Seth Rich's murder, his parents filed a lawsuit with Fox News after conspiracy theories about his murder spread across the internet. Mary Rich told NPR that the combined trauma of her son's death and the attacks by conspiracy theorists caused intense and lasting distrust. After the case was resolved, Rich's parents said in a statement at the time that they were 'pleased with the resolution of this matter and sincerely hope that the media will take genuine precautions in the future'.

It's not all about the pouches. These mammalian misfits are full of surprises, from flamboyant kangaroo showdowns to rattling koala mating calls. They might seem a bit bizarre but don't underestimate them. With unexpected superpowers and amazing adaptability, they have conquered a continent.

As training begins, the crew members process the physical, mental and technical demands being placed on them. The group is going to be in some intentionally uncomfortable situations and, to see how they do as a team. A climb of Mt. Rainier puts them to the test.

Voyager, the most ambitious space mission in history. They're the first probes to truly explore half the planets in our solar system: Jupiter, Saturn, Uranus and Neptune. These went from dots of light in the sky, to real worlds. The Voyager missions have ventured far beyond where other probes have explored. They're the first spacecraft to taste interstellar space, exploring further than any human made spacecraft has gone before. They are the greatest space mission ever. The legacy of Voyager is our remnant, it is our memory. It is a sampling of humanity that is out there now among the stars. And if they last until the death of the Universe, as the final stars fade, and everything goes dark, they will be humanity's final statement: ‘We were here.’
In the last episode of the season 10, experts explore the ultimate, ongoing mission of the Voyager spacecrafts.