Science: Searching for Extraterrestrial Life
Monday, July 21, 2008; 11:00 AM
Washington Post staff writer Marc Kaufman and planet-hunter Paul Butler were online Monday, July 21 at 11 a.m. ET to discuss the search for alien life.
Butler, who discovered some of the first extra-solar planets, will be joining the discussion from the Keck Observatory in Hawaii after a night of sky gazing.
"Few believe that the discovery of extraterrestrial life is imminent," writes Kaufman, "However, just as scientists long theorized that there were planets orbiting other stars -- but could not prove it until new technologies and insights broke the field wide open -- many astrobiologists now see their job as to develop new ways to search for the life they are sure is out there."
A transcript follows.
Marc Kaufman: Good morning. We're talking today about life beyond Earth, and the remarkable work being done by a broad range of scientists to learn what life actually is, and where else it might be found. The subject may seem far-fetched, but I can assure you the science is top-notch and the discoveries being made (and will be made in the future) are fascinating.
Joining me, I hope, is planet-hunter extraordinaire Paul Butler, which has been part of teams that have discovered about half of the planets found in distant solar systems. Paul is at the Keck Telescope in Hawaii now, and it's very early morning for him. He agreed to join us and, if all goes well, he soon will.
Everett, Wash.: If robotic probes find a planet sterile, then what are the chances of using extreme organisms on Earth to environment engineer and terraform other planets in this solar system as a preparation before humans even land there?
Marc Kaufman: I would have to say the chances are very, very small. NASA and other space agencies have protocols about making sure missions to other planets do not bring contaminants, and they're taken very seriously. I suspect this idea would run afoul of those rules. Also, we really don't know at this point what the introduction of any life form from Earth would do to another celestial body, so I can't see it happening now or in the future.
Rockport, Mass.: How many stars and how many planets are in the immediate vicinity of Earth, say 10 light-years?
Assuming that the technology of spacecraft improves by a factor of 10, how long would it take for a space probe to reach those nearby stars?
Paul Butler: The nearest star to the earth is more than 4 light-years away. Within 10 light-years, there are only a handful of stars. About 2 or 3 of these stars are known to host planets.
If our fastest spacecraft ever could go 10 times faster, it would take thousands of years to reach the nearest star.
Kaneohe, Hawaii: Since no life have so far been found any where, evolution as we know it, only exist on Earth. And since evolution is all they teach in the class room, this is like only teaching about Earth and nothing about the Universe that might entail more than evolution?
Marc Kaufman: I have to disagree with your premise on several counts. The first is that we've only been looking seriously for extraterrestrial life for a blink of time, and in a very, very tiny neighborhood of the galaxy. So there's a lot more exploring to do.
But further, the field of "cosmic evolution" is alive and well, and is teaching us enormous amounts about how the Big Bang gradually led to the formation of the first stars, and then to the production of heavy elements, and then to galaxies, etc. So while this is not biological evolution so far, it represents a kind of change that is evolution as well.
But to your larger implied question about a Creator, that's undeniably part of this discussion. Science will never be able to explain everything to everyone, and so it makes perfect sense that people will look to religious explanations. Whether or not they make better sense is, I guess, up to the individual.
Reston, Va.: What is the role for the radio telescope search for extraterrestrial intelligence (SETI)? Are the SETI League and the SETI Institute doing good work in this area?
Paul Butler: The SETI Institute not only carries out its own sophisticated radio search for extraterrestrial intelligence, but it funds efforts by other research groups as well. The people and work at SETI is excellent.
After 40 years of SETI searches, it is clear that radio transmitting intelligent creatures (or machines) are rare in our galaxy.
Arlington, Va.: Are scientists looking for evidence that life once existed or that it's possible? Are there any theories about where humans and Earth fit in a time spectrum of the universe?
Marc Kaufman: They're definitely looking for both -- that it once existed, that it may exist now, and that the conditions are right for it to exist if we can't current find it.
The task is daunting for so many reasons, and one of them is the time spectrum you mention. The universe is now believed to be more than 13 billion years old, and that the Earth has been here as a planet for more than 5 billion years. So human existence on Earth is a fleeting moment in the life of the universe. Other intelligent civilizations could easily have come and gone long ago, or perhaps are in the throes of early evolution right now.
Bethesda, Md.: Could you explain how scientists can tell there are planets circling distant stars. Are scientists sure of what they're reporting?
Paul Butler: As a planet orbits a star, it kicks the star into a small counter orbit. Newtons 3 rd law, for action there is an equal and opposite reaction. It is this small motion of the star that is detected. From the stellar "wobble" we can calculate the orbit and mass of the planet.
Columbus Ohio: It seems the task of finding water on Mars is led by the scientists from University of Arizona. I'm wondering what is the underlying organizational structure. Do you (a university research group) have to be working closely with NASA before you can land such an assignment? Or you can make a proposal anytime as long as your idea/expertise makes sense?
Paul Butler: Most NASA research programs begin as competitive proposals sent to NASA from University researchers. For example, my director at DTM proposed the NASA MESSENGER mission to Mercury, and he is the primary investigator for this program.
Alexandria, Va.: Why do you think schools are only recently developing astrobiology programs? Is the field more widely accepted among scientists now or is it because the technology has improved considerably so that scientists can do better research in this field?
Marc Kaufman: Some of both. Technology and new scientific insights have opened up the field in brand new ways, and that has led to a sense that the field is real (and exciting.) The discovery of so many strange and unimaginably hardy "extremophiles" living in acidic, sulfuric, parched, boiling hot and freezing cold environments on Earth has also created a way to find and study possible analogue organisms and environments that could survive elsewhere in the universe.
Boston, Mass.: What was the reason for halving the astrobiology budget in 2005 and do you really think the science community has enough clout to get it back to its previous numbers?
Paul Butler: The current administration has decided that going to the moon is NASAs first priority. This initially involves designing and building a new rocket since the shuttle can only go into low earth orbit and it is being retired in 2010. NASAs budget of $16 billion per year is not enough to fully fund science and the engineering needed to produce a next generation rocket capable of carrying humans to the moon. So science budgets have been cut.
Austin, Texas: I'm curious about your opinion of the Drake equation. Do you think it is useful in explaining to people the kind of work that you do?
Paul Butler: The Drake equation is a wonderful way of outlining our ignorance. When Frank Drake first proposed this in the early 60s, the only parameter that was known was the number of stars in the galaxy. Now we can make an informed guess on the fraction of stars that have planets. Every other parameter remains completely unknown. We have no idea about the fraction of planetary systems that have habitable planets, the fraction on which life develops, or the fraction that develop technology or radio telescopes. There will be work in this field for our grandchildren.
Chicago Ill.: I have no doubt that there's life outside Earth, but any such life we ever discover will almost surely be microbial.
I'm equally convinced that we'll never find intelligent life. Not because it doesn't exist, but because if our history is any guide, the kind of life we could detect has only existed for a very tiny fraction of the universe's existence. Our Earth is 4.6 billion years old, yet humans have only been able to transmit messages off-planet for what, 75 years? That's a cosmic blink of the ey (not even) -- if you scanned Earth 150 years ago you would have heard nothing. So even if there are 1 million earths scattered throughout the Milky Way, the odds are that, at any one point in time, only one or two of them have civilizations like ours.
Marc Kaufman: I agree with your general assessments, though the history of both astronomy and fledgling astrobiology is that you can expect to be surprised. Just as the Hubble Telescope allowed us to find new and stupendous galaxies and greatly expanded our understanding of cosmic evolution, technology in the future will greatly expand our ability to study the atmospheres of distant planets and determine if life exists there. And then beyond that, it's not impossible to imagine improved technology to pick up transmissions from galaxies many light years away. As we know from the presence of cosmic background radiation from the Big Bang, what's in interstellar space tends to stay in interstellar space.
Washington, D.C.: If the nearest stars, and thus planets outside of our solar system's, are so far away based on our current technology, if humans are to expand beyond Earth, is it a better bet to work on intra-solar system expansion, or improve technology to make inter-system travel more feasible? Thanks.
Paul Butler: It will be hundreds of years (at a minimum) before we have technology capable of transporting humans to nearby stars. It will be tens of years before we can send humans to Mars. NASA hopes to have permanently manned bases on the moon in 15 years. Given the sparsity of good worlds, I would hope that humans work harder on cleaning up the only place in the universe that we can inhabit.
Marc Kaufman: Nobody asked this question, but I wanted to raise the issue myself. Some people who have thought long and hard about the possible discovery of extraterrestrial life believe it could have broad implications for religious and philosophical thinking. It would, after all, be a major moment in the history of mankind.
Some think it will require adaptation from the western, Abrahamic religions that tend to see the meaning of the universe as tightly tied to the relationship of God and man on Earth. Some say it could even prove to be the new evolution. But others say it can be absorbed into religious theology quite easily.
To me it's all fascinating to consider and, given the speed of the progress in the field, perhaps important to consider, too.
Washington, D.C.: For Dr. Butler: You and your team have used iodine as a reference spectrum to measure the radial velocity of stars. Are you still using iodine, or is there another substance that will serve as an even better reference for detecting the more subtle wobbles caused by even smaller planets?
Paul Butler: We measure stellar wobbles using the Doppler effect, similar to the radar guns used to catch speeders and measure the speed of a fast ball. Doppler measurements rely on the fact that the spectrum of a moving object will be shifted in wavelength relative to the object at rest. We use the Iodine cell to provide a wavelength standard, in essence a measuring stick, against which to measure these spectrum shifts. Iodine remains the premier standard because it is directly tied to atomic physics, the wavelengths absorbed by Iodine never change.
New Orleans, La.: Maybe this is all too philosophical, but have you heard the simplistic theory of the universe that explains that all matter is or was at some time alive, and that life is built upon complex organizations of matter where it is necessary to consume more matter and energy to stay alive? Is this a possible explanation for the universe or just folklore?
Marc Kaufman: I havent heard this theory before, and it does seem highly unlikely. However, your question brings up an interesting point: Is the universe that we know and love the only one out there. To my surprise, I've found that the theory of the multiverse - that there are many universes existing in different dimensions, times and spaces -- is a serious one, and many cosmologists are inclined to think it could explain some otherwise difficult to explain realities. For instance, it appears that our universe is "fine-tuned" for life, meaning that if the basic underlying physics were even slightly different, stars wouldn't form, heavy elements wouldnt be created, and there would be no life. Some say this supports the idea of a Creator; others say it means there are many different universes out there.
Ellicott City, Md.: I think it was Fermi who asked if there is intelligent life elsewhere, why haven't they visited yet? Much as I would like to believe in alien civilizations, that's a persuasive argument to me that they don't exist. Your thoughts?
Paul Butler: The "Fermi Paradox" is very powerful. Since our galaxy is roughly twice as old as our Sun, there are billions of sun-like stars out there that are older than the Sun. If intelligent technological life developed on some of these stars, then there might be aliens out there with technology that is thousands or millions of years more advanced than our own. Such technological civilizations would have surely solved the problem of interstellar transportation, and they, or their machines, should have explored the galaxy. Yet we see no aliens, there is no evidence for aliens. So technological aliens in our galaxy must be very rare, or the problems of interstellar transport must be insurmountable.
Marc Kaufman: Many thanks for your questions. I suspect this is a subject we'll be coming back to in the future.
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