E.T., PHONE HOME: THE SEARCH GOES ON

August 31, 2008 12:17 am

BOULDER, Colo.

--Aliens are commonplace in the movies, and polls show that a substantial fraction of Americans also believe that aliens are here among us, visiting our world in UFOs. Scientists also take aliens seriously, though we remain skeptical of claims that they are already here, dropping debris in Roswell, drawing images in wheat fields, or allowing bodies to be captured and stored at Area 51. How can scientists be so interested in aliens while doubting claims of alien visitation, and what would it mean if we found indisputable scientific evidence that we are not alone in the universe?

The first part of my question is easy to answer. Looked at broadly, the history of science has gradually taught us that, contrary to what our ancestors once assumed, we are not the center of the universe. Instead, we live on one small planet, orbiting one ordinary star, among more than 100 billion stars in the Milky Way Galaxy and some 100 billion galaxies in our universe; the total number of stars is as great as the total number of grains of sand on all Earth's beaches combined.

Understanding our tiny place in a vast cosmos is both humbling and uplifting: It is humbling in the sense that there is so much more to the universe than meets the eye, but uplifting in the magnificence of the fact that, despite our small physical size, we have discovered wonders far beyond what our ancestors could ever have imagined.

Given this history, it seems almost inevitable that we will eventually learn that we are no more central to the biological universe than to the physical universe. Indeed, while we have not yet discovered life beyond Earth, scientific evidence from biology, geology, and astronomy points strongly to the idea that life should be common. In our solar system, I'll be more surprised if we don't find microbial life on Mars, Europa, or Titan than if we do. Beyond our solar system, the incredible number of stars makes it seem almost inconceivable that we could be the sole intelligence in this vast universe.

OVERLY SKEPTICAL?

Why, then, do scientists find claims of UFOs so hard to swallow? The main problem is distance. I urge readers to visit the Voyage scale model solar system in Washington, D.C., which runs along the north sidewalk from the National Air and Space Museum to the Smithsonian Castle. This model (which I had a hand in creating) represents the Sun, planets, and distances between them at one-ten-billionth of actual size. This makes the Sun the size of a large grapefruit, while Earth is the size of the ball point in a pen and about 16 yards from the model Sun.

The Moon--the farthest place that humans have ever traveled--is not even two inches from Earth on this scale. Pluto, the most distant object represented in the model, is about 600 yards from the Sun. Note that while you can walk from the Sun to Pluto in a few minutes in the model, the real distance is so great that the New Horizons spacecraft--the fastest object ever built by humans--will have been traveling nearly a decade by the time it reaches Pluto in 2015.

Now, take a guess as to how far you'd have to continue past Pluto in the Voyage model before reaching the nearest star. Got your guess? Here's the answer: You'd need to walk all the way across the United States, from Washington, D.C., to San Francisco.

MAGICAL TECHNOLOGY

That's right: On the same scale on which people have traveled less than two inches from home, the nearest stars are thousands of miles away. If aliens can travel these vast distances easily and regularly, as UFO reports suggest, their technology must be far, far beyond on our own. Such technology would be so advanced that we probably cannot even guess what it would look like, which leads me to fall back on a famous quote from the late Arthur C. Clarke: "Any sufficiently advanced technology is indistinguishable from magic." With magical technology, it's difficult to believe that crashed UFOs would be made of materials much like those we use today, or that, if the aliens wished to communicate with us, they would choose to do so by drawing pictures in wheat fields.

What would it mean to make real, indisputable contact with such a civilization? This is a question that has been explored in depth by others; for one intriguing viewpoint, I recommend the movie "Contact," based on the novel by Carl Sagan. For myself, in the short space a newspaper column allows, I'll point to one crucial idea.

GALACTIC GROWING PAINS

In the scope of galactic history, we are a civilization in adolescence. We have left behind our childhood innocence, when we could believe without consequence that the universe revolved around us. Like a teenage youth, we have power and strength that we can use to build a great future--but only if we learn to manage it well. For teenagers, success often depends on having mentors and role models from the grownups around them. But for our civilization, we are so far on our own. To me, there would be no greater benefit to making contact than that of knowing that some other civilization has made it through its own bottleneck of history--its own period of worrying about problems such as the spread of nuclear weapons, the hatred that breeds terrorism, and global warming--and successfully grown up to live among the stars.

Still, as much as I hope to see such contact, we cannot be sure it will occur, and in the meantime we remain on our own. My greatest hope is that all of us will learn to work together, so that our civilization can make its own path through adolescence. If we succeed, we will prove that, regardless of what we may find elsewhere, there is intelligent life in at least one place, right here on Earth.

Jeffrey Bennett's latest books are (for adults) "Beyond UFOs--The Search for Extraterrestrial Life and Its Astonishing Implications for our Future" and (for children) "Max Goes to Jupiter" (available in October).