Another lovely day here in Adelaide, South Australia. A maximum of 27 degrees C with nice, clear blue skies sees me at my local library reading science magazines.
As you will be aware, I keep a watchful eye on the research into extra-solar planets, and the search for extraterrestrial intelligence (SETI.)
In the "Australian Sky and Telescope" magazine (click here) for April 2011 (pages 26-35), there is a major article about SETI by one of SETI's leading researchers, Seth Shostak (click here.)
Although I keep up with SETI research, even I was surprised to read that "The number of star systems deliberately examined by SETI, looking for very weak transmissions over a wide swatch of the radio band, is only about 750, and they only received brief looks at any one given frequency." (p.27.) For some reason, I thought that this number was much higher than 750.
"The fortune so far to trip over an evidence of E.T. is akin to a search for kangaroos in Australia that gives up after examining one acre of the Outback."
The theme of the article is that modern radio searches have so far been minuscule, but that better technology may bring results by 2036
Shostak states that within 25 years, we will have searched perhaps 1 million stars instead of the 750 of today. "A million could be enough to garner success, if our galaxy's tally of transmitting civilisations is 10,000 or more."
Part of the new technology is the Allen Telescope Array (ATA) , with 42 out of the projected 350, small 6 metre diameter dishes currently existing in place. The ATA has already begun a couple of projects including targetting strips of sky near the galactic centre, and scanning in the anti-solar direction in case someone out there has seen the earth transiting our Sun.
A second SETI approach involves "looking for flashing lights from nearby stars." (p.30.) Currently, Harvard physicist Paul Horowitz has built a 1.8m diameter optical SETI scope.
Other approaches include the detection of beamed high-energy neutrinos.
"Within a generation, our experiments will have reconnoitred just about every star out to 1,000 light years or more. " (p.33.)
The NASA Kepler planet-finding mission (click here) hopefully will reveal a number of earth-like planets which SETI can then target.
A final SETI idea revolves around "How can our SETI experiments optimise the chance of finding non biological sentient entities?" "...logic suggests that we should direct some of our SETI efforts to localities where matter and energy are plentiful..." (p.34.)
The article concludes:
"The march of progress will soon permit us to search the sky more quickly and with better sensitivity, than ever before. Our situation is akin to that of Christopher Columbus as he sailed past the breakwater of Palos De La Frontera in August 1492 and headed into the rolling swells of the Atlantic. It's still very early days, and the great excitement lies before us." (p.34.)
I found this an excllent layperson's review article of the state of SETI today.