What Lies Beneath (image) University of Colorado at Boulder Share Print E-Mail Caption Spiral galaxies like the Milky Way are shown in the center, surrounded by the circumgalactic medium, which appears as black to our eyes. However, the circumgalactic medium contains very hot gas, shown in red, orange, and white that outweighs the central galaxies. The Cosmic Origins Spectrograph on the Hubble Space Telescope is an ultra-violet spectrograph that can probe these gaseous filaments and clumps. Credit Adrien Thob, LJMU Usage Restrictions None Share Print E-Mail 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.