Everywhere we look, life exists in both the most hospitable of environments and in the most extreme. Yet we have only ever found life on our planet. How did the stuff of stars come together to create life as we know it? What do we really mean by 'life'? And will unlocking this mystery help us find life elsewhere?

It is a question that has vexed philosophers and scientists for centuries; 'What is Time?' Exactly how is our past, present, and future connected by that arrow of cause and effect that we call Time? Is time simply another dimension, just like the dimensions of space we know? Can you run time backwards just as easily as it runs forward, just as left-to-right can swap for right-to-left? If other universes exist, then what is time like in them: could their Time be different from ours? And we'll probe the biggest question about time: Is our future determined? Do we exercise free will? Or, is time merely a dream?

Can we perceive objects and events beyond the world detected by our five senses? The true limits of our human brain remain a scientific mystery. New studies in neuroscience are showing that our minds can really detect events and objects that our conscious selves know nothing about. Can we predict events in the future? Is there such a thing as a global consciousness? Could physical laws on the cusp of being discovered be at the root of all this?

Since the ancient Greeks first speculated that everything they observed in reality was the result of the interaction of tiny particles they called atoms, great thinkers have tried to find a single mathematical formula that governs and explains the workings of the entire universe. So far, though, even minds as brilliant as physicists Albert Einstein and Stephen Hawking have been unable to come up with that single grand equation of everything, also known as the theory of everything, or the final theory. Nevertheless, they continue to try, because without that final piece of the puzzle that is reality, the sum total of what we know falls a bit short of making sense.

It's called the speed limit of the universe. Einstein blew all of our minds when he worked out the Theory of Relativity, and showed that space and time were malleable substances. He also theorized that we as humans can never travel faster than the speed of light, which leaves the stars and other galaxies almost impossibly out of our reach. But the dreams of Star Wars and Star Trek are not dead. In fact, there could be ways to travel faster than the speed of light - and some of them are already being tested in labs around the world.

What is it that makes you you? Scientists are searching the brain for the core of who we are - some would call it the soul, others, our personal identity. How do we become who we are?

Unless we can turn the planet's problems into solutions, humanity may be coming to an end. Scientists are unlocking the secrets of nature to tame the elements, harness energy, and even control life. Can we hack the planet to save humanity?

Every 17 minutes, someone is killed with a gun. It's a wave of violence that political debate can't seem to stop. Is this an epidemic that scientists can help cure? Could gun crime be a virus?

Most scientists believe that you are not really you, but rather, you all. On the edge of space, buried in a black hole, or right on top of you, there could be an exact copy of yourself living a parallel reality. In those parallel worlds, you may be living your wildest dreams, or your worst nightmares. Finding them is no longer restricted to the realm of science fiction. Recent game-changing theories now suggest that if these worlds exist, intelligent life in these alternative worlds could be trying to send us messages. As scientists further unravel this astounding possibility, a new possibility emerges: the fate of our entire universe may depend on these hidden cosmic twins.

It's perhaps the biggest, most controversial mystery in the cosmos. Did our Universe just come into being by random chance, or was it created by a God who nurtures and sustains all life? The latest science is showing that the four forces governing our universe are phenomenally finely tuned. So finely that it had led many to the conclusion that someone, or something, must have calibrated them; a belief further backed up by evidence that everything in our universe may emanate from one extraordinarily elegant and beautiful design known as the E8 Lie Group. While skeptics hold that these findings are neither conclusive nor evidence of a divine creator, some cutting edge physicists are already positing who this God is: an alien gamester who's created our world as the ultimate SIM game for his own amusement. It's an answer as compelling as it is disconcerting.

Is God worshipped in other worlds across the cosmos? How might alien deities differ from our own? Have advanced aliens discovered everything there is to know about the universe, or are they too looking for answers? The answer may lie buried on Earth.

It is a nightmare that has stalked us for centuries: hordes of human beings transformed into mindless, cannibalistic monsters. Could this civilization-ending nightmare become reality? Scientists have discovered pathogens that turn insects into the walking dead. New strains of viruses are attacking humans every day. Mathematicians have calculated the likelihood of surviving a zombie virus outbreak: they’re not hopeful. Now neuroscientists are discovering how easy it is for us to lose conscious control of our bodies. Are we at risk of becoming puppets? If we were in the middle of a zombie apocalypse, would we even know it?

We feel it every moment of our lives but for physicists, gravity is the longest running unsolved mystery of the universe. Why do all objects that have mass pull on one another? Cutting-edge theories are proposing unexpected answers: Gravity could be another force in disguise, a thermodynamic mirage, or even, a shadow of a hidden holographic universe. If so, the force that holds us to the surface of the earth, and holds the earth in orbit around the sun, may be a trick of the mind. We feel it, but it may not be real. Is Gravity an Illusion?

When we look up into the sky it appears we live in a universe that is filled with light. But scientists are now certain there is far more matter in the dark portions of our universe that we can’t see or touch. There’s something hiding in the shadows. Cosmologists agree that “dark matter” has helped shape our Universe, but now they need to figure out what dark matter is. What’s going on in this hidden world? Could it have formed its own dark stars, planets, and even life forms? Could this Shadow Universe threaten our world of light?

We float along the river of time. But does that river have a source? Where did time come from? Some believe time and space are one thing, and the Big Bang started the cosmic clock. Others believe the universe existed for almost half a million "years" before light could move and time began. Still others say time is older than our universe. But what if time itself is an illusion? Incredible new experiments may hold the answer. One groundbreaking experiment gives us the power to punch holes in time…and another may create a machine that operates outside time’s boundaries!

Einstein's Theory of Relativity says that time travel is perfectly possible — if you're going forward. Finding a way to travel backwards requires breaking the speed of light, which so far seems impossible. But now, strange-but-true phenomena such as quantum nonlocality, where particles instantly teleport across vast distances, may give us a way to make the dream of traveling back and forth through time a reality. Step into a time machine and rewrite history, bring loved ones back to life, control our destinies. But if we succeed, what are the consequences of such freedom? Will we get trapped in a plethora of paradoxes and multiple universes that will destroy the fabric of the universe?

Every cosmologist and astronomer agrees: our Universe is 13.7 billion years old. Using cutting-edge technology, scientists are now able to take a snapshot of the Universe a mere heartbeat after its birth. Armed with hypersensitive satellites, astronomers look back in time to the very moment of creation, when all the matter in the Universe exploded into existence. It is here that we uncover an unsolved mystery as old as time itself — if the Universe was born, where did it come from? Meet the leading scientists who have now discovered what they believe to be the origin of our Universe, and a window into the time before time.

In the premiere episode of the second season, Morgan Freeman dives deep into this provocative question that has mystified humans since the beginning of time. Modern physics and neuroscience are venturing into this once hallowed ground, and radically changing our ideas of life after death. Freeman serves as host to this polarized debate, where scientists and spiritualist attempt to define 'what is consciousness,' while cutting edge quantum mechanics could provide the answer to what happens when we die.

It is commonly theorized that the universe began with the Big Bang 13.7 billion years ago. But since we can only see as far as light has traveled in that time, we can't actually make out the edge of the universe. Could it be that the universe is infinite? Is there any way to find out what the shape of the universe really is? Can we find the edge, discover what might lie beyond it, and perhaps even discover a universe next to ours?

We move and live in three dimensions: length, width, and height. However, Einstein revealed what was once unimaginable: time is actually a dimension and linked with space itself. To reconcile the massive cosmic and miniscule quantum worlds, physicists are realizing four dimensions may not be enough. They're unraveling up to eleven dimensions. How could this be true? Where could these dimensions be?

As scientists peer across the galaxy, a new revelation emerges: The universe is shockingly organic. Are the secrets to the life and death of the universe hidden not in physics, but biology? Could it be that the universe is alive?

Scientists are peering inside the mechanisms of aging, tampering with the cellular makeup of our DNA, and imagining a world where death is cured like a disease. Are we entering a new age of immortality? Or is dying necessary for our race's survival?

Science fiction writers have always had their little green men. But these humanoid aliens were based soundly on Earth-based life, not any extra terrestrial evidence. Today, we've discovered hundreds of planets around other stars. As we learn what some of these alternative Earths might look like, science and imagination have allowed us to use real science to imagine the biology of their inhabitants. Will they have two eyes? Two legs? What color will their skin be? Which species on Earth can give us clues about likely biology of aliens? And what can we learn from how life on Earth developed to help us understand what ET really looks like?

Mankind longs for proof that we are not alone in the universe, but the moment of first contact will certainly mean the end of the world as we know it. Whether that is a bad thing for humanity or the start of a great future is uncertain.

How different are the races? Is there even such a thing as race? Could technology create a superior race? The answer may tell us where humanity is headed, what our descendants will look like and how they will think.