SPIEGEL ONLINE: Mr. Drake, after searching for decades, no extraterrestrial signal has yet been found. Are we alone in the universe?
Drake: We are definitely not alone. At the same time, I think it will be very hard to find the extraterrestrials. If they are only slightly more advanced than we are, they may be using technologies that don't reveal them. Not because they are trying to hide themselves, but because of the fact that every evidence that we find of extraterrestrials has to come from some form of energy that is wasted. If they are clever, they will be using technologies that do not waste energy.
SPIEGEL ONLINE: The SETI project, though, is searching for radio-signals from other worlds. Does that mean that, if something is found, it will be from civilizations that are not terribly advanced?
Drake: A civilization may remain detectable through radio-waves only for a short time, maybe 100 or 200 years. That means that primitive civilizations like ours are the easiest to detect. We are wasteful. Almost all the energy that we send out with radio-transmitters, for example for our television systems, does not go to earth. It does not even arrive on earth just goes off into space.
SPIEGEL ONLINE: That means that the first thing that extraterrestrials get to see from us could be the daily soaps.
Drake: That is very scary. Particularly at night there are so many crime programs on television, violence and blood and all that. That is a really inaccurate picture of our civilization.
SPIEGEL ONLINE: And last year, we even sent a commercial for tortilla-chips.
Drake: Oh, we did? I didn't know that! I think that's a stupid waste of resources. It doesn't make sense in any way. How should extraterrestrials buy our tortilla-chips?
SPIEGEL ONLINE: And what if the first extraterrestrial signal that we receive on earth is a cosmic commercial?
Drake: Actually, one of my worst nightmares is that we find a signal and it will be an advertisement for a religious cult.
SPIEGEL ONLINE: Why would that be a nightmare?
Drake: I want to learn more about a civilization than just its belief in the supernatural. Religion is an important part of the culture but may not help to improve the quality of life in a civilization. Maybe their religion is a really good one, but I doubt it.
SPIEGEL ONLINE: That makes it sound like you're not religious.
Drake: I am not a religious person.
SPIEGEL ONLINE: Does mankind devote enough resources to the search for extraterrestrial life?
Drake: There is no limit to the resources that we can use. We have technology that basically cannot be improved. But we need more of it. We have to search millions of stars, millions of frequencies. And we may have to do it over and over because they may not be transmitting all the time. It all comes down to money. For instance, in Germany you have beautiful radio-telescopes but they have never been used for SETI. The radio-astronomers are afraid that they will be criticized by the government. Nobody wants to have their funding cut because they seem to invest public funds in a project that could sound as if it was of dubious value.
SPIEGEL ONLINE: Public enthusiasm seems to play an important role. In the SETI@home project, individuals donate some of their computing power to the search for extraterrestrial life.
Drake: Indeed, we have 280,000 active participants. Recently the numbers have gone down a little bit. That might have to do with the recession.
SPIEGEL ONLINE: When can any of those people realistically expect to find the first signal?
Drake: The project, I hate to describe it this way, is very similar to gambling. It is like playing the lottery. You know that with any given ten minute search your chances of success are maybe one in ten million. But it could happen with the next analysis. A lot of the people who work for SETI@home are just gamblers. The bets are free, you don't have to pay anything. But if you win, you win very big.
SPIEGEL ONLINE: In 1970, the so called Wow-Signal was detected. For a short time, mankind thought that we heard from the extraterrestrials for the first time.
Drake: I never thought so. I was pretty sure it was an artefact, a glitch as we call it.
SPIEGEL ONLINE: So, what was it?
Drake: We simply don't know. People have spent hundreds and hundreds of hours searching the very same place on the very same frequency. And it has never been seen again. If you see a signal only once in, it is not a conclusive discovery. You have got to see it several times.
SPIEGEL ONLINE: But when mankind itself sent a message to space, the so called Arecibo code, it was sent only once.
Drake: Officially, we sent it only once, for three minutes. The signal had information coded on it, which I think would quickly be recognized by experts in other worlds. But on the day before the official ceremony, we were transmitting the message for practice for hours. The sole problem was that the antenna of the Arecibo telescope was not moving. So a whole lot of stars got 12 seconds of the message, which comes down to 120 characters.
SPIEGEL ONLINE: Messages to outer space such as the Arecibo transmission or the "Pioneer" and "Voyager" spacecrafts have been criticized for being overly centered on humans. Would you like to rewrite the messages?
Drake: I would still center it on humans. Maybe it is narcissistic, but it is what we think the extraterrestrials are interested in. They do not want to know what our dogs are. They want to know what humans are like. We had a lot of discussions as to whether we should present our best image - or a really realistic one. We decided for an ideal one.
SPIEGEL ONLINE: Some people argue that it is not a very good idea to alert other civilizations about our existence at all.
Drake: There are paranoid people who believe that they might come and attack us. But that is a faulty argument. We very thoroughly reveal ourselves through our regular broadcasts. Anything that we intentionally send is just a small addition to a great cacophony of signals that has been sent out.
SPIEGEL ONLINE: Should we be afraid of some form of a cosmic invasion?
Drake: On average, any extraterrestrial civilization will be 100 light-years away from us. There is going to be no benefit for them to attack us. It will cost an awful lot of money to launch a serious attack. So we do not need to worry.
SPIEGEL ONLINE: But how can we be sure that alien civilizations are actually peaceful?
Drake: In fact, about the time that a civilization gets the technology to make itself known, it also gets nuclear energy and nuclear weapons. And with such weapons you are always prone to a madman pushing the red button. But I am sure, that any civilization that we find, will have avoided the mad-man-scenario. They will have gotten through that bottleneck in their history and will be non-aggressive creatures.
SPIEGEL ONLINE: What could alien life forms look like?
Drake: I think it is very probable that these life-forms are carbon-based. We are usually very biased towards thinking that extraterrestrials are like us. But that is just because we do not know what else to think.
SPIEGEL ONLINE: With digital TV, with satellites, with optical networks, mankind on earth becomes less detectable for extraterrestrials. Should we intentionally send signals to alert them that we are here - and did not kill ourselves in the meantime?
Drake: In the next few years, some of the main signs of our existence are going away. And they will not be replaced -- at least in the foreseeable future -- with something that will be equally good at revealing our presence. But intentionally sending signals at present would be a waste of resources. We are still detectable because of our radio transmissions. And it will stay that way for the next 50 years. By that time we could think about building solar powered radio-transmitters. The cost of operations would be zero once these things are built.