'In Search of Beethoven': takes a comprehensive look at the composer's life through historical research and Beethoven's biography and letters, but with the emphasis always on the performance -- and interpretation -- of Beethoven's music. From his early piano concertos through the "Moonlight Sonata," "Für Elise," and the immortal notes of the Fifth and Ninth Symphonies, Beethoven's music remains as beloved, popular, and relevant as any work of art has ever been. "In Search of Beethoven" brings together the world's leading performers and experts on Beethoven to reveal new insights into this celebrated composer.

Odds are excellent that extraterrestrial life exists. So why haven’t we found aliens out in the galaxy? Are we looking in the wrong places? New research shows we should look closer to home, even inside our bodies. It turns out that a lot of our DNA is from a mysterious, nonhuman source. Theoretically, alien microbial life can make the journey to Earth from distant worlds, and scientists are finding some unearthly microbes in our upper atmosphere. Could it be from outer space? Could we be part alien? It’s even possible alien life is already here as digital life forms, hiding inside our technology.

Take another walk on the wild side with our favourite pets. Extraordinary photography reveals their hidden senses and secret communication skills. Dogs take a car trip through Paris, using their legendary sense of smell to show us a very different city. A hamster uses his remarkable senses to stage a great escape and then deploys more navigational talents to find his way home. Cats become intoxicated on the scent of a plant and suffer the consequences. A budgie shows his hidden charms to his mate as, under UV light, his crown and cheeks positively glow. Goldfish reveal secret senses that can detect the slightest water movement. A guinea pig gives birth and the newborns receive surprising care from their father. In South America, where guinea pigs have lived with people for 7,000 years, they express the true meaning of their entertaining calls. When we groom a horse we speak their language, but horses use ears to communicate in ways that we are rarely aware of. In Japan cats show their secret messages and in Peru dogs reveal the hidden signs that allow them to communicate across a city. Packed with extraordinary facts and wild behaviour - you'll never look at your pet in the same way again

The final part reveals how our knowledge of cells has brought us to the brink of one of the most important moments in history. Scientists are close to repeating what has happened only once in four billion years - the creation of a new life form.

This episode explores the wave theory of light as studied by mankind, noting that light has played an important role in scientific progress, with such early experiments from over 2000 years ago involving the camera obscura by the Chinese philosopher Mozi. Tyson describes the work of the 11th century Arabic scientist Ibn al-Haytham, considered to be one of the first to postulate on the nature of light and optics leading to the concept of the telescope, as well as one of the first researchers to use the scientific method. Tyson proceeds to discuss the nature of light as discovered by mankind. Work by Isaac Newton using diffraction through prisms demonstrated that light was composed of the visible spectrum, while findings of William Herschel in the 19th century showed that light also consisted of infrared rays. Joseph von Fraunhofer would later come to discover that by magnifying the spectrum of visible light, gaps in the spectrum would be observed. These Fraunhofer lines would later be determined to be caused by the absorption of light by electrons in moving between atomic orbitals when it passed through atoms, with each atom having a characteristic signature due to the quantum nature of these orbitals. This since has led to the core of astronomical spectroscopy, allowing astronomers to make observations about the composition of stars, planets, and other stellar features through the spectral lines, as well as observing the motion and expansion of the universe, and the existence of dark matter.

From flightless cormorants hunting underwater to giant tortoises courting on the rim of an active volcano, a look at the hidden side of Galapagos, revealing why it is such a fascinating showcase for evolution.