The periodic movement of the solar system through a potential dense disk of dark matter could dislodge objects from the Oort Cloud, increasing the probability of catastrophic asteroid impacts on Earth

“the fun proposal was that the solar system orbits around the Galaxy and as it does so it goes a little bit up and down kind of like horses on a Carousel and the suggestion was every time it goes through you have an enhanced probability that you would dislodge something from the edge of the solar sys”

He claims human activity is currently driving a massive sixth extinction event.

“The thing is is all of this is not to say that humans are off the hook. All evidence that's coming in now is showing that we are doing a lot to speed up extinction events and create a mass extinction. So much so that the big five is possibly the big six.”