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.
Eleanor Imster has helped write and edit EarthSky since 1995. She was an integral part of the award-winning EarthSky radio series almost since it began until it ended in 2013. Today, as Lead Editor at EarthSky.org, she helps present the science and nature stories and photos you enjoy. She also serves as one of the voices of EarthSky on social media platforms including Facebook, Twitter and G+. She and her husband live in Tennessee and have two grown sons.