Black Hole Activity (video) Kyoto University Share Print E-Mail Loading video... Caption An international research team reports that the activity of such phenomena can be observed as visible light during outbursts, and that flickering light emerging from gases surrounding black holes is a direct indicator of this. The team's results, published in Nature, indicate that optical rays and not just X-rays provide reliable observational data for black hole activity. The video shows violent optical variations observed from V404 Cyg (circled) on Jun 23, 2015. The flickering of visible light continued for 3.5 hours. Credit Michael Richmond/Rochester Institute of Technology Usage Restrictions Please credit Michael Richmond/Rochester Institute of Technology 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.