Wish we could do polls here but I'd be interested in folks' thoughts about approximately when they believe the following will happen.

1. Identification of a potentially habitable zone Earth-mass planet around another star. Mass ~0.3-2.0 Earths (arbitrary).

2. Detection of a life-bearing planet.

3. Detection of an extraterrestrial intelligence.

I think that Kepler is a lock to find #1. But Kepler results won't really be definitive until after many transits are observed; not a long time for planets closer to dimmer stars. Don't know Kepler's minimum visual magnitude. Meanwhile, other efforts like HARPS might find something. I'd say it's safe to say that between 0-5 years there's a good 90% probability we'll find something. My bet is within 3 years, by 2010. I hope to lose to a shorter timeframe.

As to life-bearing, we'd need evidence of a biosphere. A leading step would be detection of water vapor and of course free O2. But biology could be indicated by the presence of many different molecules that should by natural processes react and be removed from an atmosphere. Biological processes keep renewing restoring these constituents. This is a difficult technological challenge. I don't see this happening this decade or next. Unless NASA's planetary science program is gutted to fund social entitlements, I think it likely that a space telescope in the 2020s does detect indications of a extra-solar biology. My date is 2027. All this of course assumes that the probability of life arising is reasonable. If as some biologists claim the probability of spontaneous generation of living things is 10 exp -30 or so then we and algae are unique. Then it's up to us to green the Local Group.

Number 3 is not readily susceptable to rational analysis. It's personal belief lightly constrained by what littlee we know in science. My bet is not this century.

What are your thoughts & why?