Ok so the “facts” are not irrevocably proven, but there is strong evidence that the estimates are in range and agreed by countless scientists who study astronomy. When I say billions or trillions of galaxies everyone is agreed that it is at least hundreds of billions because we can see them, and the ones we can’t see, but theory says they must be there would take it into the trillions. The point is that there are a lot of stars. Given that we have found 11’000 stars with 18’000 planets, given that we know we should only be able to see the very large planets, not small ones like Earth, Mars or Venus, it is reasonable to deduce it as a fact that there are more planets than there are stars. Our star has 9 of them. The evidence is emerging that there is nothing unusual about our star. Simply put there are a lot of stars, with even more planets. Probability says there will be plenty like ours, both older and younger. I think it fair to describe it as a fact. Imagine you took 11’000 random used bank notes on which you could only see half the serial number. You find that the number 9 occurs 18’000 times. It would be perfectly reasonable to state that most bank serial numbers contain the number 9. That’s good enough statistics to be described as a fact. You don’t have to check every note in existence before calling it a fact.

By the way I did get one fact wrong. The nearest star is about 4.2 light years away, not 2 light years. Incidentally, scientists have already identified that this star, Proxima Centauri, has at least ONE planet and a SECOND possible planet is awaiting verification. The planet found is INSIDE the HABITABLE zone. Our technology isn’t good enough to say what the chemical mix is, but we do know that the mass is between 1.2 and 3.0 earth masses, meaning it could be a rocky planet like our earth.

There is always a question when you call a theory a fact. It’s a grey line. I am happy to call something a “fact” if the statistical evidence is overwhelming which I believe is the case.