SPT CMB diagram (IMAGE) DOE/Argonne National Laboratory Caption The cosmic microwave background — the universe’s oldest light — has traversed vast distances before reaching us. During its extended journey, gravitational forces from massive cosmic structures caused its trajectory to bend before being captured by the South Pole Telescope. Credit (Image by Zhaodi Pan/Argonne National Laboratory.) Usage Restrictions none 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.