You've felt cold before. Sometimes it's cold outside. But what if I told you that "cold" isn't real? There's no substance or quantity called "cold" in science. We can't measure the amount of "cold" in something. Instead it's about what's NOT there.
Early Earth was a canvas for the vast new palette of the colours of life, with the diversity of human skin tones telling the story of how humanity spread and ultimately conquered the planet. Dr Helen Czerski explores the true masters of colour - which are often the smallest and most elusive - travelling to the mountains of Tennessee to witness the colourful mating display of fireflies, and revealing the marine creatures that can change the colour of their skin in order to hide from the world.
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.
In this extraordinary documentary we are going to witness very different kinds and situations of snowing: from howling blizzards to the gentlest and loveliest of weather events, from huge handkerchiefs quietly falling to the needle-sharp attack of hard, heavy grains. Snow - what is it really? How is it created - naturally and artificially? Thanks to CGI and new camera techniques we can actually see this process for the first time and listen to the incredible, inaudible music of snowfall, of myriads of tiny crystals touching and rolling and settling. Each snowflake is unique and bears more secrets than we could imagine. Did you know that different kinds of music influence the crystallization process and the shape of snowflakes? And have you ever imagined that we would be able to produce artificial snow that melts at 30 degrees Celsius? With this in mind: just let it snow!
2008 • Physics