odd sound

The reading claims that starting in the 1960 and continuing until the 1980s, sailors in Russian submarines patrolling the North alnatic and Arctic Ocean would occasionally hear strange sounds and there are several theories about what might have caused the odd sounds. In contrast, the professor states that researchers still debate about this odd sound and there are problems with theories. First, the article asserts that the first theory suggests that the strange noises were actually the calls of male and female ocra whales during a courtship ritual. However, the lecturer opposes this point by saying that this theory seems plausible but unlikely to be true. In fact, the ocra whales live in near the surface of the Ocean, and the submarines still close to the deep of it. So the ocra may detect Russian submarines. Second, the passage posits that a second idea is that the sounds were caused by giant squid. On the other hand, the professor counters this point by explaining that Russian submarines detected the sound in 1960 and continued two decades, then the sound disappeared in 1980. Actually, if the squid always live there, they have continue to live and there is no reason to stop hearing the sound 20 years. This appears a contradiction to the information made in the passage. Third, the article avers that a third theory suggests that Russian submarines were picking up stray sounds from some military technology, like another country's submarines that were secretly patrolling the area. Conversely, the professor casts doubt on this point by stating that the secret should not hold up, and the other submarines should move around and change their direction. She mentions that this other submarines should create some noise and they didn't have the technology that let them move fast and silent.