Vacuum Chamber and Aluminum Sphere (IMAGE) University of California - Los Angeles Caption The researchers constructed a vacuum chamber, roughly the size of a soccer ball, in which the pressure was one-trillionth that of the atmosphere we normally breathe. An aluminum sphere roughly the size of a marble (center), functioned as a dense object to suppress the chameleon fields and allow the researchers to measure small forces. Credit Courtesy of Holger Müller 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.