Quote from the article:
“I actually think the chances that we’ll find ET are pretty good,”
The guy quoted actually said “chances that we will find ET are pretty good”.
Sounds overly optimistic to me.
He could have been a bit more conservative by saying “chances that we could find ET are pretty good” but he didn’t.
He could have, but the point is the OP is mis-characterizing what the guy actually said. The OP’s title is ‘“SETI will find extraterrestrial life in 25 years”’ and it’s in quotes. SETI isn’t saying it WILL find anything…one guy from SETI is saying that the CHANCES that they will find something are ‘good’. Those are completely different.
As for the optimism of the guy quoted in the linked article, as Stranger says, he almost has to say stuff like that (funding and all), plus, being on such a project he probably really believes that. I remember a quote from a scientist concerning the Higgs Boson saying they would surly find evidence of it within 5 years. Or the guys looking for evidence of dark matter in mine shafts. If they didn’t believe they would find something they probably wouldn’t doing those projects…and if they couldn’t convince others that they could or would find anything, they wouldn’t convince anyone (including the public) to fund their research.
-XT
No, a documentary is something like Godzilla. Star Wars is known as a docu-drama, all original footage, but based on actual events.
Kepler can not only determine the period of the orbiting planet, but it can also make a good estimate of its size based on the amount of dimming that takes place. So even if the orbital mechanics of two rotating bodies wound up looking like the orbit of a single planet, the planets would also have to be the same size.
There are candidates however, that might not be planets. Kepler could be seeing a binary star system where one of the stars is much smaller and dimmer than the other. This is where secondary observations come in - once Kepler identifies a candidate, it can become a target for further ground-based and space-based observation. Once we know which stars have planetary candidates, and we know exactly when those candidates will transit across the face of the star, we can turn other instruments towards it at the right time and make further measurements.
This may be the one of the biggest gains from Kepler - a catalog of exoplanets and their transit times, which makes study of them possible with other instruments. So as we observe and come up with questions, we can devise new instruments to answer those questions.
Here’s some information on Follow-up Observations and what they can tell us.
So far, Kepler has unambiguously identified five planets in this group of stars. All of them have orbital periods of just a few days. They are mostly ‘hot Jupiters’ - Jupiter-sized planets orbiting extremely close to the star.
There are currently about 700 planetary candidates being investigated through follow-on observations and other methods. And we’re still in the very early days of Kepler. In February there’s a huge data dump to the public which will likely identify hundreds or thousands more candidates. And as time goes on, and the candidates come from further out in the solar system, we’ll hopefully more multiple-planet systems, and start to get an understanding of the typical structure of solar systems.
Kepler can measure the diameter of planetary candidates, and by measuring the star’s doppler shift as it wobbles, astronomers can determine the planet’s mass. With those two pieces of information, we know the density of the planet, and can differentiate gas giants from rocky planets.
It’s a very exciting time in planetary science. Three years from now, our understanding of extra-terrestrial planet formation is going to be much better than it is today. We’re going to know what the ‘typical’ solar system looks like (or if there IS a ‘typical’ solar system). We’ll have a good idea of how likely it is for a sun like ours to have rocky planets and gas giants, and where they are likely to be. We’ll have a good idea of how many planets orbit the habitable zones of stars.
Back to SETI - One of the more famous formulations used to determine the probability of intelligent life in the Universe is the Drake Equation:
N = R* X fp X ne X ft X fi X fc X L
Where N = the number of civilizations in our galaxy we might be able to communicate with, and:
R* = the average rate of star formation per year in our galaxy
fp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets
fℓ = the fraction of the above that actually go on to develop life at some point
fi = the fraction of the above that actually go on to develop intelligent life
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time such civilizations release detectable signals into space.
We have a pretty good handle on the R* term. Kepler is going to fill in fp and ne.
In the next 25 years, we have a decent chance of determining fℓ, at least to some degree, through astronomical observation.
The rest of it is a complete crapshoot. We have no idea for any of those values. But if we can solve the other terms, then SETI becomes an interesting piece of the puzzle and even negative results become positive results in the sense that they start giving us an indication of how unlikely it is for civilization to form (or to survive once formed).
Let’s say we discover that half of all stars of our type have planets in the habitable zone, and measures of the atmospheres of them discover that at least half of those appear to have some form of photosynthetic life. That would mean that there should be life on about 25 billion planets in habitable zones around sunlike stars in our galaxy.
Knowing that, if SETI continues to find nothing, then over time we’ll have a better and better estimate of the product of the last three terms of the Drake equation, and hopefully over time we’ll develop new experiments to help narrow down each of those terms.
Because the aliens are there, duh. Can’t have heathen freaks using up all our God-given resources, can we ? Sure, we could use the bits lying all over. But we could also use the bits lying all over AND theirs. Now I’ll ask you, which one sounds like our manifest destiny, old chap ?
I wish I had my copy of Pale Blue Dot with me. In it, Sagan says that SETI has found (IIRC) 4 signals that it can’t explain away as non-intelligent, all from the same area of our galaxy. Pretty exciting stuff.
Carl Sagan? How long has he been dead? I imagine that the questions about these signals were resolved a long time ago, or there’d be a hell of a lot more buzz.
Here’s the most famous SETI signal:
From JPL today, Kepler finds first planetary system with at least 2 planets and a possible third.
I think some folks may be misinterpreting what “we will find ET” in 25 years means.
A generous interpretation is that we will find evidence of LIFE in other solar/star systems (oxygen, methane…). Which IMO is not that much of a stretch from what we know now and the technologlies we have/are developling to answer that question with some certainty.
A stricter interpretations is that we will literally find ET. Aliens folks with technology/intelligence/whatever. Now, IMO, that ranges from also not much of a stretch to virtually impossible (given that we have no real idea of how often technological life evolves from just general life).
I think the ETs have already found us. And they put up signs warning other intelligent species away from us.
I’d presumed that the article linked in the OP was talking about searches for intelligent radio signals (that’s what SETI used to exclusively mean). Now I realize the term is used in the broader sense you mention, which makes my original snarkiness unwarrented.
Hey, I grew up on 50s pulp Sci-Fi novels, so I’m expecting disintegrator rays, scary-looking faces (in fishbowl helmets), AND a penchant for Earth maidens.
I guess I’m talking 1950’s-Style Death Rays…
My personal belief is that aliens have visited Earth in the past, took a few pictures and left. We Humans are a primitive, violent race who can’t get along with each other. The aliens realize that any contact with us humans will invariably lead to war, no matter what.
I also think that Earth is more or less in a Galactic desert, with no other Oxygen like planets around with the nearest solar system being a great distance away.
Space junk of the Earth has barely left the Solar System. That’s nowhere.
This assumes that anybody is actually transmitting and not just listening. SETI (AFAIK) does not transmit a signal. As Ferris said in his book “Mind’s Sky”, it’s very likely that nobody else is transmitting either, on the chance that a hostile civilization may decide to come find out who is making all the racket.
“Of all the sad tales
That SETI might tell,
The saddest would be
A small value for L.”
Given the obnoxious car alarm that awoke me this morning and then kept me company I have to agree on this one 
Wouldn’t we look silly if we stopped spending the pocket money we spend now on SETI and missed the aliens ?