More Evidence For Extraterrestrial Life
by Sean Hinds, age 18
Scientists searching for extraterrestrial life once faced amused skepticism. But according to Seth Shostak, senior astronomer at the Search for Extra-Terrestrial Life (SETI) Institute of California, the general concensus is shifting.
Evidence accumulated over the past few decades supports the idea that life exists outside of Earth. Since experts believe that water must be present for the development of living organisms, the discovery of the potential for water in our solar system has opened many new possibilities.
Life could exist in the oceans of Jupiter’s moon, Europa, shielded from radiation by a covering of ice, possibly subsisting near hydrothermal vents. Saturn’s moon, Enceladus, exhibits gas shooting up from its surface, indicating possible liquid water. Another of Saturn’s moons, the massive Titan, has oceans, although they may very well consist of methane. Closer to Earth, water exists underground on Mars. Discoveries like these have gradually increased enthusiasm for the search for life.
Recently, a handful of groundbreaking discoveries have even further increased the likelihood of biological organisms existing in the universe. In December 2010, scientists reported that there are three times as many stars as previously thought; this discovery makes it three times more probable that life would develop somewhere. On Earth, NASA found a microbe that can apparently survive on arsenic, broadening the very definition of life, and the conditions in which it can exist.
Scientists have also detected a host of new and often strange planets in other solar systems. Astronomers have located an extremely hot planet much larger than Jupiter, which appears to contain carbon in its atmosphere. The presence of carbon, a key molecule in all life—at least as we know it—in other solar systems makes scientists even more optimistic.
One star, when examined, revealed at least four big planets, contradicting previous theories regarding the number of large planets that can exist in a solar system. This discovery also shows that we cannot know what to expect when searching the cosmos.
Adding to these findings, scientists revealed earlier this year that they had found the first planet that they believe could harbor life.
Some skeptics have voiced concerns about these recent discoveries. The question the procedures used in NASA’s arsenic microbe research. But overall, the evidence for the existence of life elsewhere in the universe seems to be increasing. With a broader understanding of what constitutes life, and a greater number of places to look, scientists have a daunting, but increasingly more doable task: find extraterrestrial life.
Scientists currently grapple with two main questions: “how many places can support life?,” and “how easily does life develop?” They generally agree that if we find life, it likely will not have developed into the sentient, human-like beings common in movies and television. It will probably resemble a much simpler organism, possible akin to slime or mold.
Scientists have come up with an equation to calculate the odds of civilized, human-like life on another planet. They know little, however, because humans are the only actual case of civilized life they can study—that the equation is imprecise, and largely based on guessing.
Scientists will never stop searching for life. They may examine the atmospheres of far-off planets through telescopes, and look for carbon dioxide, evidence of photosynthesis; they may study meteorites as possible vessels of life. Perhaps listening to radio signals will reveal messages from other intelligent life. It may take years or decades to stumble upon anything, but the likelihood of finding something appears greater than ever.
While the first life we discover may not drive hovercars and whirl around in flying saucers, it will give us a starting point. Regarding the many still adamant skeptics, Schostak has equated believing Earth to be the only locality in the universe where life exists to believing in miracles; “and astronomers,” he says, “tend not to believe in miracles.”
[Sources: Associated Press; Scientific American]