In a vast cosmic experiment equivalent to hitting "redial," astronomers in a dozen countries are aiming telescopes to listen in once again on some of the stars that were part of the world's first search for alien life 50 years ago.
The coordinated signal-searching campaign began this month to mark the 50th anniversary of Project Ozma, a 1960 experiment that was christened the world's first real attempt in the search for extraterrestrial intelligence or SETI.
Like Project Ozma, which got its name from a character in L. Frank Baum's series of books about the Land of Oz, the new search is called Project Dorothy.
Project Ozma was conducted by astronomer Frank Drake of the SETI Institute in Mountain View, Calif. Drake is also famous for devising the Drake equation, which predicts the number of alien civilizations with whom we might be able to communicate. The formula is based on factors including the rate of star formation in the galaxy and the percentage of stars thought to have planets. Making educated guesses for some of the equation's terms, scientists have used it to predict we could find evidence of ET intelligence within the next 25 years
"It is thrilling for me to witness the beginnings of Project Dorothy, the continuation of my search of 50 years ago," Drake said in a SETI announcement. "To have so many talented people using so many telescopes in this new search, with the electronics and computer equipment of today, is a joyful thing to me. The equipment of today is far better than what we could have 50 years ago and will result in both very much better and very much more data than could be obtained then."
The anniversary observations, which began Nov. 5, will continue throughout the month. Astronomers in Australia, Japan, Korea, Italy, the Netherlands, France, Argentina and the United States are taking the first shifts, searching for signs of an intelligent civilization from a few nearby stars. [ Q&A with SETI Pioneer Jill Tarter ]
Astronomer Shin-ya Narusawa of Nishi-Harima Astronomical Observatory in Japan, who launched Project Dorothy, said: "Two of the original stars from Project Ozma Tau Ceti and Epsilon Eridani are the nearest solar-type stars in the northern hemisphere. Therefore, these two stars were the best SETI targets a half century ago. They remain the symbol of Project Ozma and are two of the target stars for Project Dorothy."
The new search includes some particularly promising targets for extraterrestrial intelligence, including stars with known planets, which modern telescopes were only recently able to detect. The scientists are aiming for stellar systems where planets are thought to orbit at roughly the right distance from their suns to hold liquid water and thus, possibly, life.
"Project Dorothy vividly demonstrates just how far SETI has come in the past 50 years," said the SETI Institute's Douglas Vakoch, who is a member of Project Dorothy's working group. "The lessons learned through Project Dorothy provide critical preparation for the day we finally detect a signal from another civilization."
Though the searches undertaken by astronomers at the SETI Institute and elsewhere over the past 50 years have not found indications of little green men, experts say it's too early to give up hope.
"Over the past 50 years our searches have not yet produced the discovery we all hope for," Drake said. "This is understandable in our vast and awesome universe it will take long, painstaking and comprehensive searches before we will have a good chance of success. This is the major lesson learned from previous searches. Project Dorothy is a major step in meeting the challenge created by this lesson."
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