Sources: Nature [journal paper], Science [journal paper], University of Alberta [press release], The Guardian
quote: Right, but it's more like a pendulum swinging back and forth, and the species are all subject to the whims of the pendulum's magnitude. In many instances, if humans feel threatened by that same swinging we can just build a new pendulum.
quote: We've seen other planets forming but we have yet to discover another planet that's like ours, or even some shadow of what earth used to be throughout its development.
quote: but I do not think that the true story of how earth came to be the way it is today is an open and closed book.