How far back in time could I go and still live?

Factual Questions
21

[QUOTE=DrCube]
I vote for the Cambrian. Then you could go fishing! You’d have to sleep on the rocks, though, or turn the old time machine into a boat, since there wasn’t any land life at the time.
[/QUOTE]

And you could get down with the funky Discomedusae!

22

[QUOTE=Scuba_Ben]
To the best of my limited knowledge of paleoecology, a typical modern person could probably survive even in the Triassic age, without the benefit of hazardous-environment gear.

Aside: Your time machine can project back 4 billion years? I’m impressed – the one I’m working on can only project back about 500 years. Where precisely is your lab? I want to Get There First and examine your system.
[/QUOTE]

I’ll meet you in Paris on Dec 18, 1750 and show you.