I just read an article about the distant space collision meant doom for dinosaurs. I sat back and thought about it for a moment. I seem to like this notion that this kind of collision played the role. I'm keeping my mind open on other hypotheses and theories. It's worth reading.
On other note, I do believe that the asteroid has caused the catastrophe about 65 million years ago. The crash was powerful enough to put Earth in dark for a period of time. My biggest question is how did mammals survive? Did a fraction of plants survive without the sunlight ray? I have thought about the continuous activities of volcanoes that may have allowed the small group of plants at unaffected area to survive.