Photograph courtesy of T. Sahai and J. Trauger/SPL/NASA.

The Boomerang nebula, above, is the coldest known spot in the universe. A dying star at the center expels gas at 100 miles per second, forcing the nebula to expand rapidly and to cool to 2 degrees Fahrenheit above absolute zero. This image from the Hubble Space Telescope reveals enigmatic banded structures in the exceptionally dense outflow from the star.