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June 8, 2004
Dr. Laurance Doyle, astrophysicist at the SETI Institute, knew very early on that he wanted to be an astronomer.
"My dad gave me a map of the solar system when I was six," he says. "What surprised me was that the stars are suns. I remember my thought shifting off the earth and it was never back on earth again. That's when I knew I would be an astronomer."
However, it wasn't that easy for Doyle. Growing up on a dairy farm in Cambria, California (near San Simeon, best known as the site of Hearst Castle), he didn't have much access to information about stars. But with encouragement from his parents, and by reading science books from the local library, Doyle was able to sustain his passion for astronomy. It was no surprise then that he obtained his Bachelor's and Master's of Science degrees in astronomy from San Diego State University.
Armed with those degrees, he took a job at the Jet Propulsion Lab as an imaging engineer, analyzing pictures of Jupiter and Saturn sent from the spacecraft Voyager. He then went to Heidelberg, Germany, to help analyze images of Halley's Comet sent from a spacecraft. While there, he got his doctorate in Astrophysics at the University of Heidelberg, graduating in the 601st year of the university's existence.
Doyle made his way to the SETI Institute in 1987 as a principle investigator studying extrasolar planets.
Information Theory
Among Doyle's current projects is seeking to compare dolphin whistles and baby babble in order to make predictions about extraterrestrial communications. The connection may seem tenuous, but he believes that by measuring the complexity of communications for different species on earth, we could get a good indication of how advanced an extraterrestrial signal is, and where humans might be found on that scale.
"If we can learn the rules of communication by understanding the languages of other species on earth, we'll be much more prepared to deal with an extraterrestrial message if and when it comes," explains Doyle.
The Animal Communications project utilizes Information Theory, a mathematical formulation developed for quantifying the amount of information sent through telephone lines to determine how much information dolphins are whistling back and forth to each other. His study determined that babies babble over 800 different sounds with the same amount of frequency as dolphin babble. As they grow older, those sounds are limited to roughly 50, become very repetitious, with a few sounds that are used more often than others. His study found that baby dolphins develop similarly with regards to their whistling.
"We recorded dolphin whistles and they gave the same distribution as human language. And that surprised us," says Doyle. It provided "mathematical proof that dolphin whistles are not random."
Claude Shannon, the Bell Lab scientist who first introduced Information Theory, determined that there are rules that govern the English language. For example, Shannon generated random letters, telling the computer the letter E occurs the most; T occurs the second most; A occurs the third most, etc. The computer was able to generate letters with the correct consonants and vowels with the correct frequency of occurrence. Shannon then gave the computer rules for generating letters as they relate in pairs and trios, for which the computer returns the correct English text.
"What we're trying to do with dolphins, humpback whales and other species is we're trying to work in the other direction," explains Doyle. "We have a significant volume of text and we want to see if there are any rules we can back out. We start to look at relationships between these signals and see how complex it gets."
Eventually, Doyle would like to chart the communication complexity of several species, including plants, squirrel monkeys, dolphins, humpback whales, and humans.
"What if we get an extraterrestrial signal that's not 9th order but 20th order in complexity," theorizes Doyle. "Right away, we know their communication ability exceeds ours by about as much as ours exceeds ground squirrels. In other words, we're going to know where we stand right away. Even an extraterrestrial transmission would have to obey the rules of information theory."
Detection of Extrasolar Planets via Photometry
Another of Doyle's current projects is detecting extrasolar planets utilizing photometry. Doyle uses photometry in three different ways to measure the brightness variation of stars. The Photometric Transit Method uses an algorithm to look for the shadow of a planet as it goes through the disc of a star. The algorithm is a mathematical way of quantifying if there really is a transit or an oscillation in the atmosphere.
Another method, the Phase Reflection Method uses sinusoidal variation (similar to the orbiting of the moon from new to full) to detect giant planets as they go through phases orbiting near their stars. Eclipsing Binaries is the third planet detection method for stars that come in pairs and eclipse in front of each other regularly. By timing the eclipses, astronomers can determine whether there is a planet nearby, offsetting those eclipses.
PlanetQuest
PlanetQuest is perhaps the project about which Doyle is most passionate. It is educational in nature and allows everyone to participate in the search for extrasolar planets.
"I see this as turning everyone into astronomers," exclaims Doyle. "It isn't just reading about it. And it isn't just supporting something. It's turning people into the explorers. It's turning them into bona fide astronomers with the opportunity to discover something, and soon."
PlanetQuest software allows amateur astronomers to download, images of high-density star regions. The assigned star would be tracked using the computers spare CPU cycles.
"The basic idea is they pick out a star and their computer measures the brightness of the star and compares it with brightness variations that are typical of different kinds of variable stars," says Doyle.
The program is connected to the PlanetQuest website which would provide a reference for the user as to what he or she is discovering. There is also a cataloguing system that will allow the user to be credited with any discoveries.
While only one in 3,000 to 5,000 stars will have planets going across it, all stars will be doing something, claims Doyle. "Sometimes they just sit there like the sun and create a nice stable habitable zone," he saids. "Sometimes they pulsate and are interesting as distance indicators or for studying stellar stability or evolution."
Doyle believes that participating in searching the universe is a great way for people to set aside differences as they seek something relevant to everyone, on the planet.
"We need to connect," he says. "The universe is huge now. I really feel like we need something to unite us and connect us together. In a worldwide search for worlds revolving around other stars, I think that has a possibility of helping to unite people."
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