Sterile version of earth dscovered

I f we were to discover a planet that was basicaly a sterile version of earth with no organic traces of past life what would be the process to infect it with life and how long before it might become habitable or self sustaining?

Just poop in a mud puddle, and they’re off & running!
Life (not just Dinosaurs) finds a way.

You wouldn’t even need to poop. Everything from our planet is contaminated with life, whether we like it or not. Probes that have sat on the surface of the Moon for decades still have viable bacteria on them.

The OP isn’t clear on exactly how similar his Earth-prime (E’) is to ours. And many geophysical facts about Earth are strongly driven by our current and historical bioshere.

I’d suggest that a sterile E’ will have approximately zero free oxygen. It will all be bound up in crustal rocks.

So Job One would be to get some life-based processes going to free up the oxygen. So first we need to infest the place with photosynthetic cyanobacteria.

Then wait a few dozen million years for oxygen to become abundant enough to start introducing more typical Earth species of aerobic bacteria. Which in turn after a few million years provide the substrate for plants and, even later, animals.

See Great Oxidation Event - Wikipedia for more.

Hmm that seems pretty complicated, LSLGuy. Isn’t there some way to do it with a modified photon torpedo? Think I read about that somewhere.

Well in Total Recall all it took was some giant alien toaster vaporizing a bunch of subterranean ice to get Mars a breathable atmosphere and pressure.

I’m sure we could work out something similar?

We did a variation of this quite recently.