Planets beyond our solar system are known to astronomers as exoplanets. They are at trillions of miles from Earth and yet, it might be possible to detect a faint signature of life in them. From the light of the stars they orbit that passes through the atmosphere of an exoplanet, it is possible to capture the chemical fingerprint of the elements in that atmosphere.
The fictional world Eden is orbiting not one star, but two. The light from its twin stars powers photosynthesis, pumping more oxygen into the atmosphere than in Earth, allowing life to thrive. Grazers are constantly alert to danger, because the canopy is home to predators perfectly evolved to live among the trees. In Episode 3, another topic are fungi and the role they could play on exoplanets. Ecologist Thomas Crowther talks about the role mycelial networks play in the Rothiemurchus forest in Scotland.

By the time he died in 1931, Thomas Alva Edison was one of the most famous men in the world. The holder of more patents than any other inventor in history, Edison had achieved glory as the genius behind such revolutionary inventions as sound recording, motion pictures, and electric light. Edison's curiosity led him to its cutting edge. With just three months of formal schooling, he took on one seemingly impossible technical challenge after another, and through intuition, persistence, and a unique team approach to innovation, invariably solved it." Driven and intensely competitive, Edison was often neglectful in his private life and could be ruthless in business. Challenged by competition in the industry he'd founded, Edison launched an ugly propaganda campaign against his rivals, and used his credibility as an electrical expert to help ensure that high-voltage electrocution became a form of capital punishment. Edison explores the complex alchemy that accounts for the enduring celebrity of America's most famous inventor, offering new perspectives on the man and his milieu, and illuminating not only the true nature of invention, but its role in turn-of-the-century America's rush into the future.

Questions are raised about the search for intelligent life beyond the Earth, with UFOs and other close encounters refuted in favor of communications through SETI and radio telescope such as the Arecibo Observatory. The probability of technically advanced civilizations existing elsewhere in the Milky Way is interpreted using the Drake equation and a future hypothetical Encyclopedia Galactica is discussed as a repository of information about other worlds in the galaxy. The Cosmos Update notes that there have been fewer sightings of UFOs and more stories of abductions, while mentioning the META scanning the skies for signals.

Brian asks how, from a lifeless cosmos, it is possible that a planet can produce the more than eight million species we know of.

Over the last years, the world has experienced an energy revolution, driven by an urgent need to green the grid and save life on Earth as we know it. 50 years ago, a devastating oil crisis kicked off an energy revolution. The world set course to cut the costly habit of burning fossil fuels. With the urgent new threat of a changing climate, the drive to unleash the power of the sun, earth and wind has accelerated into a race for humanity's survival. Change is taken place but, is it happening fast enough to secure our future? Technologies are right here, right now, and they will enable the transition to 100% renewables, because winning the energy race means a win for the entire world.

NASA may have just gotten one step closer to the answering the question: are we alone? The Spitzer Telescope has made a groundbreaking discovery of exoplanets that could be similar to our own. And as Kepler also continues its search, our understanding of the universe continues to be redefined.