Transcription: There have been a lot of theories about what caused the extinction of the dinosaurs and other animals. One hypothesis for which there's quite a lot of supporting evidence is that an asteroid or maybe a comet struck the Earth about 65 million years ago, producing a huge explosion which cut off the Sun from the face of the Earth and affected the climate for many years afterwards. Now, the relative abundances of the elements are not exactly the same in different parts of the universe, neither as we mentioned earlier. is the isotopic composition of the elements and it's possible to identify extrat ...