One of the Universe's most enduring mysteries is Time Travel. In this episode, we explore the possibilities. Discover why Time Travel into the future is unavoidable in the Einsteinian world of Relativity. As for the past... the laws of physics do not tell us it's impossible, but the bizarre consequences of going into the past and altering the future make for mind-bending science. Finally, we go for the future by traveling to the nearest star, 4.3 light years away... in only 45 days. Our destination may be an Earth-like planet; a planet scientists are now hunting for, and may find in the next 3 to 4 years.

A look at how the Sun was formed and how it could potentially die; its physical composition; how it makes energy; and the nature of solar eclipses, solar flares and sunspot activity. Behold the sun and all of its glory. Learn all things about the sun ranging from its beginning to its death. Also learn about how stars work in general and MUCH, MUCH more.

Our Sun has served Earth well for almost five billion years. It's bathed us with heat and energy. But like humans, our home star is mortal. In five billion years, it will stop nurturing its planetary offspring. The aging star will bloat out beyond the orbit of our planet incinerating all living things--including humans if we're still around.

For one night only, Professor Brian Cox goes unplugged in a specially recorded programme from the lecture theatre of the Royal Institution of Great Britain. In his own inimitable style, Brian takes an audience of famous faces, scientists and members of the public on a journey through some of the most challenging concepts in physics. With the help of Jonathan Ross, Simon Pegg, Sarah Millican and James May, Brian shows how diamonds - the hardest material in nature - are made up of nothingness; how things can be in an infinite number of places at once; why everything we see or touch in the universe exists; and how a diamond in the heart of London is in communication with the largest diamond in the cosmos.

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.

In part two, Professor Al-Khalili looks at the 19th century chemists who struggled to impose an order on the apparently random world of the elements. From working out how many there were to discovering their unique relationships with each other, the early scientists' bid to decode the hidden order of the elements was driven by false starts and bitter disputes. But ultimately the quest would lead to one of chemistry's most beautiful intellectual creations - the periodic table.