There was an annular solar eclipse near where I used to live (about 20 years ago). It is pretty well certain that it did happen, because eclipses can be reckoned precisely and the likelihood of anything affecting my memory of an entire day is extremely low.
But is it a "fact" that there was an eclipse then? Leaving aside questions of location, I am simply saying: can there be facts concerning things which have already occurred? I thought that facts are things we know for certain, and if there was some unknown which intervened or made the recollection wrong, it would be a false belief instead of a "fact". Is this why my Philosophy professor said that we can't know things in the past?
(For reference, one definition of fact includes the phrase: "something that has actual existence". But if an event is no longer the case, it does not have actual existence, therefore there can be no facts about the past. A definition of the word Exist is: "Anything that can be acknowledged in the present, exists.")