Guth explained that there were problems with Big Bang cosmology. For one, the Universe is mysteriously uniform in all directions. If you position telescopes at the North and South poles, and point each of them at a dark patch of sky, you can catch light from opposite ends of the Universe. If you measure the temperature of light from these regions, all the way out to eight digits, you’ll see the same number. This is mysterious because the two regions are separated by more than 20 billion light years, too far to have ever interacted in a way that would lead to such extraordinary equilibrium. It’s possible to generate a uniform universe such as ours within the standard Big Bang framework, but you have to carefully calibrate its initial conditions. You have to ‘fine-tune’ it.