“Detecting nothing—even when it’s 1 billion light-years wide—is not easy. It took observations of radio galaxies, temperature, and a bit of conjecture. Lawrence Rudnick, the astronomer who led the team that found the void, was studying data from the Very Large Array, a network of 27 radio antennas in New Mexico, when he spotted a gap in the constellation Eridanus where radio signals from galaxies appear unusually faint. He matched this gap with an enormous ‘cold spot’—colder than the frigid temperatures of deep space—in the cosmic microwave background, the leftover radiation from the Big Bang. ‘We knew we could connect these two things, the lack of radio galaxies and the cold spot,’ Brown says. ‘It’s the easiest explanation—you don’t have to invoke any strange cosmologies to explain it.'”
The Ice-Cream Scoop Taken Out of the Universe. A patch of the heavens that contains far more nothingness than the rest of space, by Stephen Ornes, November 21, 2007
Day-yam, I love science, really I do.