Follow scientists on their quest to understand and capture the first image of a black hole while exploring the limits of our knowledge of the universe.
Extra dimensions of space — the idea that we are immersed in hyperspace — may be key to explaining the fundamental nature of the universe. Relativity introduced time as the fourth dimension, and Einstein’s subsequent work envisioned more dimensions still — but ultimately hit a dead end. Modern research has advanced the subject in ways he couldn’t have imagined. John Hockenberry joins Brian Greene, Lawrence Krauss, and other leading thinkers on a visual tour through wondrous spatial realms that may lie beyond the ones we experience.
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.
Deep underground in a vault beneath Paris lives the most important lump of metal in the world - Le Grand K. Created in the 19th century, it's the world's master kilogramme, the weight on which every other weight is based. But there is a problem with Le Grand K - it is losing weight. Professor Marcus du Sautoy explores the history of this strange object and the astonishing modern day race to replace it.
At the Palace of Westminster, Helen teams up with scientists from the University of Leicester to carry out state-of-the-art measurements using lasers to reveal how the most famous bell in the world - Big Ben - vibrates to create pressure waves in the air at particular frequencies. This is how Big Ben produces its distinct sound. It's the first time that these laser measurements have been done on Big Ben. At the summit of Stromboli, one of Europe's most active volcanoes, Helen and volcanologist Dr Jeffrey Johnson use a special microphone to record the extraordinary deep tone produced by the volcano as it explodes. Finally, at the University of Cambridge's Institute of Astronomy, Helen meets a scientist who has discovered evidence of sound waves in space, created by a giant black hole. These sounds are one million billion times lower than the limit of human hearing