Astronomers have discovered the largest structure yet seen in the universe, a clump of quasars so large that it would take light 4 billion years to traverse its widest dimension. Light from these quasars started its journey when the universe was only 5 billion years old, the researchers say. Far larger than previously discovered groups of quasars, the structure (artist's depiction of a single quasar) is so large that it challenges Albert Einstein's cosmological principle—the notion that the universe, at large scales, looks the same no matter the direction and locale from which you look. According to that theory, the researchers say, the universe's large-scale structures—in this case, clumps of objects such as quasars—shouldn't be larger than 1.2 billion light-years across. The elongated, newly discovered large quasar group (LQG) is, on average, about 1.63 billion light-years across but in its largest dimension is more than 4 billion light-years across, the researchers report today in Monthly Notices of the Royal Astronomical Society. By comparison, typical clusters of galaxies can be nearly 10 million light-years across. Bringing the comparison to our cosmic neighborhood, the new record-holding group of quasars spans about 1600 times the distance between our Milky Way galaxy and our neighbor Andromeda.
See more ScienceShots.