The Search for Extraterrestrial Intelligence (SETI) has been high on my list of interests for one primary reason: there are probably billions of more advanced civilizations out there somewhere and some might be beaming to us the solutions to world peace, cancer, fusion and who knows what. I even once worked at the NASA Ames Research Center in 1976 on Project Orion to design a system for finding an extrasolar planet. One of the key questions in those days was: Is this the only solar system in the Universe? It was not until 1995, nearly twenty years later, that a giant planet (larger than Jupiter), 51 Pegasi b (a drawing by Celestia to the left), was found around a star by that name minus the b, 50 light years away (our closest star is Alpha Centauri at 4.37 light years). I'm of the contention that we could have accomplished this task almost immediately after 1976 using a technique I designed with the inspiration of Nobel Laureate Charles Townes.
So let's go back to the basics, mostly from the Scientific American issue of this month entitled:
The field of astrophysics appears to only bless two techniques for discovering extrasolar planets:
- wobble (below): shifting of a star's movement caused by a revolving planet, scientifically called astrometry
- transit: the diminution of starlight if a planet passes across it (this reduction is on the order of 1 in 10,000), the technique used by Kepler (right)
With all those rocket scientists around, how much more crude can these two techniques be? Oh, there are half a dozen fancy titles for other schemes, but they all are based on these two methods. Astrometry accounts for more than 95% of the nearly thousand (907 as of 4July2013) findings.
I have a third option, a direct method in the optical spectrum, that is, measuring discrete monochromatic colors emanating from extrasolar planets. In 1976 when I arrived in the Bay Area to work for NASA, I was able to find accommodations at Escondido Village, where Stanford graduates students can live, across the street from Wilbur Hall, my freshman dormitory. What a summer, as I showed up at Ames a few hours/day, golfed at the Palo Alto Municipal Golf Course (kind of mediocre, but it was cheap), took a wine tasting course at night and rented the largest TV set I could find, a giant 36 inch mega box, where I could watch the the Montreal Summer Olympics.
Mind you, I was still largely doing research, as, for one, I had just read that Charles Townes had reported something very interesting: planetary atmospheres lased (principle above), with the wavelength depending on the molecule. Starlight can be 10 million times brighter than that of their planets, thus, it is essentially impossible to "see" the planet from Earth. However, as a laser is at a specific frequency, I thought it might be possibles to track this fine wavelength with special equipment, which, granted, more than third of a century ago might not have then been available.
So I went to see Professor Townes, who had just moved to the University of California at Berkeley from the Massachusetts Institute of Technology. He was encouraging and thought my idea might just work. Unfortunately, I mischievously entitled my instrument the Planetary Abstracting Trinterferometer, or PAT, which was not appreciated by the NASA leaders of the program. One, because of the acronym, but second, for the whole thing was a play on words of the interferometer the rest of the group was designing for Orion according to NASA protocol, which is to avoid the optical spectrum. Mine was just three telescopes placed at optimal equilateral distances several thousand miles apart, so I should have called it the Planetary Abstracting Telescope system. One was sufficient, but three would have multiplied the precision.
More recently, Palomar Observatory's Hale Telescope staff developed a high-contrast imaging system that may be actually capable of spotting extrasolar planets. To the right is an image of a star with...? This would make it a slam dunk and double the benefit with PAT because the wavelengths would then help determine the atmospheric composition. If there is no lasing, then there is no atmosphere, so it's not worth bothering with that planet.
The cost of PAT? Relative to NASA projects, peanuts. The Hubble Telescope, which was initially projected to cost a third of a billion, ended up at more than $10 billion, and should be good for another five years. The James Webb Space Telescope (JWST) is already at $10 billion, and won't be launched until 2018 at the earliest. Anyway, this next generation version will continue to use rapidly obsolete methodologies. There is also the upcoming $5 billion Terrestrial Planet Finder, but I think Congress finally terminated this effort, although NASA continues to spend several million dollars each year to keep it alive. This sum would be all PAT needs, and can be accomplished from Planet Earth. PAT is awaiting a researcher to provide a simple and cheap solution for extrasolar planetary detection.
In the meantime, my attitude has shifted, so I'm not advocating even bothering with PAT. In 1976, yes, let's go confirm a planet outside our solar system. Now? Why bother to find any more, as we have found a thousand, and astronomers have already said that there could be more than 100 billion Earth-like planets in our galaxy that could be home to life. Further, there could be 500 billion other galaxies in our Universe. Let's expand our efforts to detect possible signals from aliens. On with SETI! Bring back Jodie Foster, sometimes known as Jill Tarter of the SETI Institute.
In the meantime, my attitude has shifted, so I'm not advocating even bothering with PAT. In 1976, yes, let's go confirm a planet outside our solar system. Now? Why bother to find any more, as we have found a thousand, and astronomers have already said that there could be more than 100 billion Earth-like planets in our galaxy that could be home to life. Further, there could be 500 billion other galaxies in our Universe. Let's expand our efforts to detect possible signals from aliens. On with SETI! Bring back Jodie Foster, sometimes known as Jill Tarter of the SETI Institute.
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