At one point, in 1961, Ed had wanted to examine one of the solutions in greater detail, so he stopped the computer and typed in the 12 numbers from a row that the computer had printed earlier in the integration. He started the machine again and stepped out for a cup of coffee. When he returned about an hour later, he found that the new solution did not agree with the original one. At first he suspected trouble with the machine, a common occurrence, but on closer examination of the output, he noticed that the new solution was the same as the original for the first few time steps, but then gradually diverged until ultimately the two solutions differed by as much as any two randomly chosen states of the system. He saw that the divergence originated in the fact that he had printed the output to three decimal places, whereas the internal numbers were accurate to six decimal places. His typed-in new initial conditions were inaccurate to less than one part in a thousand.And the rest is ... not exactly history, because the field is still getting wider and wider.
I was reminded of Ed Lorenz by this video (8 minutes) on the subject How can climate be predictable if weather is chaotic?
It is, I think, a very good resource for answering people who pose this question, that is, if they are not incorrigibly pig-headed.
In my younger days, it all seemed straightforward as to how come we have rocky planets in the inner part of our Solar System, and gas giants further out. However, with the discovery of more and more exoplanets, it has become apparent that our own system is rather unusual. But so many of the other systems seem so weird: especially, how have so many “hot Jupiters” formed so close to their parent stars? Some years ago, in the last century probably, a visitor came to the University of Reading Physics Department to give a colloquium entitled Chaos in the Solar System, which introduced me to the topic of planetary migration. I came away feeling that our system was not as stable as I thought, but watching this video (18½ min) leaves me thinking how lucky we are, on two counts. One, that we have a habitable system at all, two, that we’re unlikely to have been surrounded by aliens who visited our world before we even got here.