I suppose zero is a pretty significant number.

Without new physics that isn’t even remotely visible on the horizon and that utterly contradicts most of what we believe to be true, this isn’t going to happen. Robotic AI probes sent to other star systems to send back telemetry? Sure, fine. Flesh bags sent to self-replicate on terraformed worlds out in the stars? Not a whisper of a microscopic chance.

If you can sent probes to other star systems, you can include with it information of the DNA of life forms and a device to create terran life.