The researchers used the Subaru telescope in Hawaii to observe a region 300 million light years in width. They discovered that roughly 1 billion years after the Big Bang, some areas in the universe were denser than others. Normally dense areas mean more gas, leading to the formation of more galaxies. But found the opposite to be true. The reason is believed to be the inability of UV light to travel long distances during that point in time, making those areas seem darker.