Alvarez hypothesis

The sex lake theory is not in the slightest plausible or accepted in any capacity by the scientific community, just so we´re clear. I personally greatly dislike many dinosaur extinction pet theories because they are disingenuously focused on dinosaurs when a load of other animals went extinct as well and those pet theories almost always come down to a poorly thought out idea as to what would make non-avian dinosaurs vulnerable. Among those pet theories I´m personally amused by the ´theory´ the dinosaurs died due to increasing gravity, which of course so splendidly explains why we have the largest theropod, one of the largest sauropods, and the largest pterosaurs right before their extinction /s Personally I subscribe to the idea the meteor impact was the chief factor but was compounded strongly by the Deccan traps. More on reddit.com

The paper that proposed the impact hypothesis gives a quick summary in its introduction: Many hypotheses have been proposed to explain the Cretaceous-Tertiary (C-T) extinctions, and two recent meetings on the topic produced no sign of a consensus. Suggested causes include gradual or rapid changes in oceanographic, atmospheric, or climatic conditions due to a random or a cyclical coincidence of causative factors; a magnetic reversal; a nearby supernova; and the flooding of the ocean surface by fresh water from a postulated arctic lake. These weren't necessarily all regarded as equally likely--I think Alvarez is just trying to give a sense of the broad range of proposals here--but the overall point is that there was no single consensus, aside from perhaps a slight preference towards some kind of climate change (because, as it turns out, climate change seems to be a factor in pretty much every major extinction event). More on reddit.com

For the record, it's well beyond a theory at this point. It's undeniable that it was an asteroid that killed the dinosaurs, or at least that it triggered the spiraling climatic affects that did them in within a few hundred or thousand years. In fact, recent revisions suggest it was actually two asteroids. It would be foolish and anti-intellectual to try to come up with other theories based on little or no evidence given the level of evidence available proving it was asteroids. The leading theories before we knew to test for uranium in the sediment was worldwide, violent volcanic eruptions and dwindling food sources, or the idiotic, original theory that "they were God's failed creations and therefore doomed to die as they lumbered about, stupidly." More on reddit.com

Geologist Walter Alvarez noticed iridium (a substance found in meteors and not naturally rarely found on Earth) at a certain layer at a dig site. He asked other geologists around the world to see if they could also find iridium at the same level and all did. Given that dinosaur fossils ended at this level, he wondered if a meteor could have wiped them all out. Fortunately his father was Nobel Laureate Luis Alvarez. They did the math and determined that a meteor of the right size could have done it. So they went looking for a crater of the right size and age. That took a while because as it turned out, the one they were looking for was on the bottom of the ocean and only known by oil company geologists who don’t write academic papers. Eventually they found it and confirmed their hypothesis. Walter still teaches at the University of California at Berkeley. I wrote to him years ago to thank him for his work. More on reddit.com