ALMA Boomerang (IMAGE) National Radio Astronomy Observatory Caption This is the Boomerang Nebula, a pre-planetary nebula produced by a dying star. ALMA observations show the hourglass-shaped outflow, which is embedded inside a roughly round ultra-cold outflow. The hourglass outflow stretches more than three trillion kilometers from end to end (about 21,000 times the distance from the Sun to the Earth), and is the result of a jet that is being fired by the central star, sweeping up the inner regions of the ultra-cold outflow like a snow-plow. The ultra-cold outflow is about 10 times bigger. Credit ALMA (ESO/NAOJ/NRAO), R. Sahai Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.