It's a mystery mankind has struggled to solve since the beginning of history - is space infinite or might there be great cosmic border where everything ends? Groundbreaking cosmology and state of the art space telescopes, now suggest the Universe has a finite size and a unique shape. If this is true, there must be an edge to the Universe, and beyond that edge, there could exist a world beyond our wildest dreams.
Our galaxy is one of hundreds of billions in the universe. View of universe through the Hubble telescope and go back almost all the way to the Big Bang.
Are we alone? SETI--the Search for Extraterrestrial Intelligence--is a privately funded project using radio telescopes and optical telescopes to scan the stars for signals.
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.
Is there another Earth out there with liquid oceans, rocky continents and life like us? Astronomers seek the answer with spectroscopy, direct imaging and telescopes. They hope to find evidence of atmospheres, magnetospheres and signs of life.
