Northwestern Podcast on LIGO's 2 Chirps (AUDIO) Northwestern University Your browser does not support the audio element. Caption Listen to Northwestern astrophysicists Vicky Kalogera and Shane Larson discuss the two different 'chirps' detected by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors. Credit Northwestern University Usage Restrictions Must use credit. License Licensed 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.