Let’s say a rogue planet or something came close enough to Earth to knock it out of its orbit. Whatever event causes this, can this happen without disrupting human life in the short term and how long can I stretch this period where life is mostly the same? I figure at some point society will collapse, but I’d like write about the moments before that.

I’m interested in a realistic answer, and a bonus question is: could this event happen in a way where the moon stills orbits the earth? Or at least still follows the earth as it gets further and further from our sun.