So in the future a lot of people think time travel will become a reality, with people able to travel millions of years in the past or thousands of years into the future, to see what Humanity has become, what our planet has become. With this comes uncalculated risks, for example by travelling millions of years into the past some people think that the slightest change we make, like stepping on a creature that has not managed to multiply yet, could have cataclysmic effects on the course of the Human race, we could change our entire existence. One mistake and humanity may never be. So my question is if time travel becomes possible, how big would the affect be if one person, that's all just one, made a mistake in the past, changed the past on the course of humanity and this planet?