research method (IMAGE) University of Washington Caption In this artistic rendering, light from a distant quasar passes through the halo-like circumgalactic medium of a galaxy on its way to Earth, where it is measured by Hubble's Cosmic Origins Spectrograph to determine the composition of the halo. Credit: NASA/ESA/A. Field Image URL: https://hubblesite.org/contents/media/images/2011/37/2930-Image.html?news=true Credit NASA/ESA/A. Field Usage Restrictions Must include credit License Original 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.