There's evidence that dark matter makes up 85% of all the matter in the universe. We can see dark matter holding galaxies together and ripping other structures apart, we even see it bending light. Dark matter itself has been around since the beginning of the universe. Without dark matter, we wouldn't be here. But if you can't see dark matter and if you can't touch it, does it really exist?
Dark Matter is thought to be the cosmic glue that holds the universe together, yet the search for it continues to eluded scientists today.

Experts explore the elusive endeavor of determining the age of the cosmos. Understanding the age of the universe is fundamental to understanding the universe at all. It's at the heart of everything. We want to know how much mass is in it, how much energy is in it, how it behaves. We have to have this number nailed down. The age of the universe enables us to not only understand where we came from, but potentially, the fate of the universe, what will happen millions and billions of years from now.
The idea that the universe grew from a ball smaller than a pinhead is hard to understand, but figuring out when it happened sounds like it should be more straightforward. But it turns out, getting the age of the universe is pretty tricky.

Chris turns to longevity doctor Peter Attia to find out how changing his eating habits can help his quest for longevity. Ironically, the answer is to eat no food at all for four long days. If he can bear the hunger, fasting will unlock his body’s own anti-aging powers and give Chris the edge he needs when he tries to hunt for his next meal … by spearfishing off the Great Barrier Reef.

The images of brothers Tamerlan and Dzhokhar Tsarnaev are released to the public setting off a violent chain of events. Meanwhile, clues from their past tell a complicated story - how was the radicalization of the ethnically Chechen brothers and the existence of potential collaborators. The post-9/11 biases played a role in the investigation.

Following their identification, the Tsarnaev brothers killed an MIT policeman, then kidnapped a man in his car. They had a shootout with the police in nearby Watertown, during which two officers were severely injured (one of whom, Dennis Simmonds, died a year later). Tamerlan was shot several times, and his brother Dzhokhar ran him over while escaping in the stolen car. Tamerlan died soon after.
An unprecedented manhunt for Dzhokhar ensued, with thousands of law enforcement officers searching a 20-block area of Watertown. Residents of Watertown and surrounding communities were asked to stay indoors, and the transportation system and most businesses and public places closed. After a Watertown resident discovered him hiding in a boat in his backyard, Dzhokhar Tsarnaev is cornered into an intense standoff. As officials navigate remaining questions and suspicions, the city emerges Boston Strong.

Predators and prey are in an arms race for survival. Hunters and hunted deploy hidden super- skills in the battle to eat or be eaten. Masterclasses in predatory perfection are vital to passing on skills. So when they're ready to hunt for real, the next generation is fully prepared for the battle between predator and prey.
Life is a mission, survival. Animals have evolved secret weapons and hidden skills to outsmart their enemies. So in those life or death moments, it takes the most extraordinary super powers to prevail.