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Spacecraft like the proposed Terrestrial Planet Finder can be used as part of an incremental strategy to search for life in the universe, one that can sustain public interest over long periods of time. (credit: NASA/JPL)

Space exploration at a crossroad

Part 2: What should we do?

There are probably three questions everyone asks at some point during his life: a) What happens after death?, b) How did everything begin (and will end)?, and c) Are we alone in the universe?

Of course, the first question has nothing to do with space exploration. The second, on the origins and destiny of the Universe, is a very complex one on which astronomers are working very hard. Unfortunately, their works consist mostly of fundamental astrophysics research that is often difficult to understand, even for well-informed laypeople.

But that’s not the case for the third one, which is for the moment at the crossroad between ground-based astronomy and space exploration.

Finding if we are alone in the universe concerns many areas of science: biology, chemistry, physics, astronomy, and state-of-the-art technology. With ground-based telescopes and space observatories, astronomers have already found hundreds of planets around stars in our galaxy—a prodigious achievement. Unfortunately, because of the techniques they use, most of these planets are massive gas giants bigger than Jupiter, not Earth-like worlds.

On the other hand, astronomers using space-based telescopes are observing planet formation around young stars. These studies are significant because they show us how and where life could begin and how abundant planets could be.

Astrobiologists tell us that to find life somewhere in the universe, we should look for little rocky planets, preferably Earth-like planets orbiting in the habitable zone of a stable star. However, others point out that exotic life forms could exist in strange places, such as below the Martian surface, in the oceans of Europa under kilometers of ice, or in evn more exotic locales.

What is fascinating about all this research is that progress is being made in many fronts at the same time. What’s more fascinating is that progress could be even greater in the next decade with the use of extremely powerful space telescopes.

The quest for life in the universe is at the crossroad between ground-based astronomy and space exploration.

For example, in 2009, NASA will launch Kepler, an observatory that will survey our neighborhood to detect and characterize hundreds of Earth-sized planets. In 2013, it plans to launch the James Webb Space Telescope, the “Hubble Space Telescope of the 2010s” that will study every aspect of the universe, from the Big Bang to the formation of planetary systems capable of supporting life. Later on, NASA hopes to launch the Terrestrial Planet Finder, which will be able to analyze atmosphere of distant worlds to find out whether they could harbor life.

At present time, the search for life in the universe is not a big-ticket program like the Space Shuttle, ISSn or Constellation. It makes astonishing advances anyway but at a slower pace than if we allow it the same resources.

The quest of our time

The search for life in our neighborhood is perfectly fit for our time because it takes into account all of the lessons we could glean from past programs. First, of course, it tackles something that the public does care about, answering a question everyone is asking. Second, it’s not a decade-long wait-until-we’re-ready program. As we’ll see below, this is a progressive quest involving a number of steps. Third, not only there is no need to oversell its importance, but this quest does not need as many resources per year as piloted spaceflight.

With perhaps one or two billion dollars a year, we will have plenty of money to do whatever needs to be done. So, at a time of severe budget limitations, the president could choose to tackle other priorities, maybe other space activities or urgent needs here on Earth, and still finance our search for life in our galaxy.

Imagine, for instance, that we invest just a third of the resources we’re putting into piloted spaceflight in the search for life in our neighborhood. After some years of preparation, we will be able to launch a number of powerful specialized space telescopes to look for Earth-like inhabited planets. This armada—and the many scientists and engineers required to build and operate them—will be needed because there is so much to look for: probably hundreds of stars with maybe thousands of planets or, as Carl Sagan would have said, billions and billions of possibilities!

We could imagine that our quest will begin with Planet Finders, spacecraft that could discover planets that are more and more like Earth. Some of them orbit in the habitable zone of stable stars. Maybe there are hundreds or thousands of such planets. Then, with more powerful Planet Analyzers, we may be able to find which ones possess an atmosphere around them and liquid water on their surface.

Finally, with Life Finders, we can analyze these atmospheres to look for specific signs of life. For example, we could look for the content of an atmosphere to see if it is full of toxic gases or of free oxygen. Perhaps some day we’ll find planets with atmospheres that looks like our primordial Earth at the time when oceans had contained only primitive algae. Maybe we’ll find planets with what could be signs of early plants and animals… or something like dinosaurs or even mammals. And maybe, one day, we’ll find a planet with a polluted atmosphere, a sign of an industrial civilization like us!

The greatest endeavor of all time?

Or course, there are plenty of possible scenarios and the one above will probably not happen as is, since we should expect many surprising developments. But what’s important to keep in mind is that our quest for life in our galaxy will be fascinating to follow year after year after year.

And that continued progress is important to sustain public interest. Looking at past big-ticket programs, they were sold to the public by saying that after a decade or two of technical preparations, we will have a space shuttle that will give us cheap access to space, or a space station that will revolutionize the way we do things here on Earth, or that we will go back to the Moon to prepares ourselves to go to Mars. But, in the meantime, the public has to wait and hear about delays, cost overruns, and technical problems. Obviously, during this long wait, their attention shifts away to other priorities.

By contrast, our quest to find if we’re alone in the universe is a progressive one. As illustrated above, we’ll make interesting discoveries all the way, discoveries that bring us closer and closer to our goal.

Our quest for life in our galaxy will be fascinating to follow year after year after year, that continued progress is important to sustain public interest.

Some discoveries will even be absolutely fascinating of their own for laypeople. For example, just think of the day we’ll find some Earth-like planet orbiting in the habitable zone of its star. “Is there life on it?” will be the question everyone will be asking. “Oh, we don’t know… yet!” scientists will answer. Another day, we’ll find a planet on which some breathable life form modifies its atmosphere. “What kind of life there is?” people will ask. “Well, we don’t know… yet!” will be the answer. And if someday we find some “industrious life” polluting its atmosphere, public will demand: “Are they like us? What do they look like? Could we contact them?!” “We don’t know… yet!”

What a fascinating quest it will be. And it could happen in the next 10 to 15 years!

Does it means that we will solve one of the greatest quests of humankind in the next 10 to 15 years? No, unless we hit “the jackpot.” But whatever happens in the meantime, if will have profound impacts on who we think we are.

For instance, consider that after thousands of stars are scrutinized and maybe hundreds or thousands of planets analyzed in detail, we found no life or, more probably, no advanced life form. We wouldn’t be able to conclude that there is no one else in the universe, but perhaps we are not numerous… or that maybe we are “exceptional” (or something else).

On the other hand, if we find inhabited worlds, how many? Will it be hundreds, or only one or two? Whatever the answer to this question, it will be very exciting, won’t it?

So, will we chose take the public along on ne of the most exciting endeavors of all time? Or we will continue to explore space as we’re doing now? We have to decide!