The Universe Is Larger Than We Think

The universe is larger than we think, says David Walliams. He explains how light bends in a way to make bright bands and dark bands with no sharp edges at all. In experiments about the precise shapes of shadows, he uses lazer light instead of torchlight because it can cast multi-coloured fringes. If you increase the number of slits through which light can come,  you seem to increase the amount of shadight that can come from one slit. Ay, lots and lots of light with one slit - long defraction process.