Are We Alone?
from Through the Wormhole; We've all done it, stared into the night sky, gazed at the vast canopy of stars and wondered what or who is out there? Is there other life in the universe? Maybe on a planet like ours with water and air? Or on some other kind of planet or moon supporting an alien form of life? We would think we were all alone, and then sometimes people would just appear out of the darkness. Could our universe be just as deceiving? Might other sentient life-forms just appear out of the seeming darkness of space? There are more stars in the universe than all the grains of sand on every beach on Earth, and countless planets orbit those stars. So it would be arrogant to think that we are the only creatures in the cosmos. I think it's easy to imagine life on other worlds, and I'm not alone. A whole category of scientists investigate alien life. They're called Astrobiologists. Lynn Rothschild of the NASA Ames Research Center is one of them. The Murchison meteorite was more than just a piece of rock floating through space. It was a doorway to alien life. A piece of the meteorite is kept here at the California Academy of Sciences. The reason this is so exciting to scientists is that it's as old as the solar system, and yet we found that it contains the building blocks of life, things like amino acids and other sorts of chemicals that we use to make our own bodies and all life on Earth. So what it shows is that these building blocks were around in our solar system before life arose on the Earth. Life may have come to Earth in a meteorite like this, and life similar to ours may be spread through the universe in the same way, as meteorites act like seeds, raining down the ingredients for life on fertile planets. So what does this mean for our hunt for E.T.? Dr. Jill Tarter is SETI's chief alien hunter. If you'd like to listen to the cosmos, take an old-fashioned radio like this, an analog radio, and tune the radio between stations. And you hear that hiss? About 10% of that noise is actually coming from the cosmos. That's synchrotron radiation from the Milky Way Galaxy. SETI has combed the cosmic radio dial for 50 years. Most days, it's quiet out there, but once in a great while something exciting happens. In 1977, a SETI astronomer picked up a signal from the constellation Cagittarius. It lasted 72 seconds. The full duration, the radio telescope was pointed at it. Going through the data, the scientist circled the signal and wrote, "wow!" The signal looked like the kind of engineered pulse that we expect will come from an alien civilization. The "wow!" Signal was a one-time event. Astronomers have returned to that part of space looking for the signal, hoping for a repeat, but always coming away disappointed. Professor Paul Davies is a physicist and SETI affiliate. But he's something of a heretic within the group. The traditional approach to SETI is to scan the skies with the radio telescope in the hope of picking up a message from some alien civilization that's been deliberately beamed towards Earth. I don't think that's credible, and here's why. One of the big problems in this whole SETI business is the vast scale of things. The universe is really, really big. By human standards, it's just stupendously big. Astronomer Geoff Marcy hunts the sky for planets that could sustain alien life. You might as well be looking for fairies or for alien civilizations in the pyramids. It's hard to believe, but until recently, there was no proof that other planets exist outside our solar system. In 1995, his patience was rewarded. A group of Swiss astronomers had their eyes on a bright object in the Pegasus constellation called 51 Pegasi b. The Swiss suspected they had found what everyone was looking for, a very large planet, the first one seen outside of our solar system. But they needed confirmation. Luckily, my student, Paul Butler, and I had telescope time assigned to us just a week later on the Lick Observatory 3-meter telescope four consecutive nights, and as luck would have it, the supposed orbital period of this planet around 51 peg was four days. Perfect match. We went to the telescope. All four nights were clear. We measured the Doppler shift of 51 peg, and we drove off the mountain 100% convinced that the Swiss had been correct. It was a marvelous moment, and the world was introduced at that time, in mid October '95, to the notion that our solar system was not alone. The discovery of 51 Pegasi b changed the entire game. The Doppler shift method of planet detection was proven successful, and soon Marcy and his colleagues found more and more alien worlds. Here we are, about to answer a question that the ancient Greeks asked and humans undoubtedly asked even before then. It's a treasure of a moment in human history that we suddenly have at our fingertips the telescopes, the computers, the light detectors, and the knowledge to answer a philosophical question that humans have been asking since antiquity. The answer to that question "Are We Alone?" May come sooner than we think. Because for the first time ever, we have an undercover Detective not tied to the Earth, but floating in the heavens... A special Agent in space specifically designed to track down E.T. In its native habitat. On march 6, 2009, NASA launched the Kepler Space Telescope. Kepler is the first-ever satellite solely devoted to the hunt for planets outside our solar system.
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