Will a sign from God will convince us of his existence?

[Fidel_Castronaut]

Okay try this one...suppose the name Jesus was found inscribed on the cell walls of a bacteria presumed to have been present since the dawn of creation...

That you would even propose such a bizarre hypothetical as something that could convince us to accept this Jesus bloke (whoever that was) as a god (whatever that is) I think speaks volumes about this entire discussion.

But as others have said, if it stood up to scrutiny and was the last and importantly only reasoned explanation as to why it would be the case left after all others had been eliminated, it would be compelling in that given time frame.

Of course, the next day someone could come up with another more evidenced explanation and blow it right out of the water.

And that's the beauty of science; it's never static. It's always changing as claims are are countered/updated with other claims that have more evidence (or a better explanation of the available evidence) behind it.