Tags John Batchelor Dr. Karen Meech Dr. David Livingston interstellar comet Borisov Comets interstellar Oumuamua comet intelligence hyperbolic orbit not bound by sun's gravity large telescope sky survey comet shape comet tail comet gassing carbon nitrogen content comet chemistry Ort Cloud left over debris theory Dr. Avi Loeb gas ejection deviation comet rendezvous Guest John Batchelor Dr. David Livingston Dr. Karen Meech Tagline interstellar comets including the new one discovered, Borisov View the discussion thread.