The Boomerang Nebula is a protoplanetary nebula located 5,000 light-years away from Earth in the constellation Centaurus. Researchers took the nebula’s temperature with the Atacama Large Millimeter/Submillimeter Array (ALMA) and learned it is a frigid minus 458 degrees Fahrenheit (minus 272 degrees Celsius).
That makes the Boomerang Nebula the coldest natural place known in the universe.
The Boomerang Nebula is believed to be a star system evolving toward the planetary nebula phase. A planetary nebula has nothing to do with planets. It’s a phase of life for older stars, when they slough off their outer layers, creating a cloud or nebula around the star. In the Boomerang, millimeter-scale dust grains mask portions of the nebula’s center so most escaping visible light is in two opposing lobes forming a distinctive hourglass shape as viewed from Earth. The outflowing gas is moving outwards at a speed of about 164 km/s and expanding rapidly as it moves out into space.
This gas expansion results in the nebula’s unusually low temperature.