By the way, I have no doubt that human civilization can have risen and fallen repeatedly in the course of geologic time.
Young Engineers are always accused of trying to reinvent the wheel but I'm pretty sure that humans have done exactly that, more than once.
The thing is there are no good records for Mass natural catastrophes except the geologic evidence we can dig out of places that have been hit, and the ancient legends of such things which survive in the history of various cultures around the world.
Many cultures have stories of great floods and great earthquakes and great disasters of the past. the fact that human being still exist means that some of us escaped to tell those Tales.
I am 100% certain that this will happen again and that only a fraction of humanity will escape destruction.
Everybody's worried about global warming that could kill us all off in another Century or two, but we take no account of the fact that an out-of-the-ecliptic asteroid could smack into the Earth and put the survivors in an ice age in a matter of days.
Is it possible that ancient civilizations developed things like anti-gravity fields and cold fusion?
First you have to consider the rise of technology in our own situation. We went from beating out steel plates and rivets with a hammer, to Hot Drop forging, to computer-controlled 3D "printing" in a few hundred years. In another hundred years the situation could be equally astonishing.
Should we survive.
you only need to look at the Moon to decide that there have been a lot of asteroid strikes in our past. After all, the Earth attracts asteroids six times as strongly as the Moon.
Over the eons the pummeling has abated, but there is no reason to believe that most life on Earth won't be extinguished by a big rock falling from the sky.