Priscilla Frisch, University of Chicago (image) University of Chicago Caption Priscilla Frisch, Senior Scientist in Astronomy and Astrophysics, and member of the science team, Interstellar Boundary Explorer. Collaborating with former University of Chicago astronomer Thomas F. Adams, she made the first spectrum of interstellar hydrogen inside the heliosphere using data from the Copernicus satellite in 1975. Hydrogen and helium gas dominate interstellar space beyond the heliosphere. The spectrum showed that the hydrogen had the velocity expected of interstellar gas, proving its origin. Credit Jason Smith Usage Restrictions News organizations may use this image in connection with news reports about the work Priscilla Frisch and her IBEX colleagues. 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.