16 May 2011

Green Bank Telescope looks for ET

The impressive list of planet candidates created by NASA's Kepler space telescope, 1235 to date, has given new impetus to the search for life in the Cosmos. Recently, the Allen Telescope Array (ATA), consisting of 42 radio telescopes, and heart of the SETI (Search for Extra Terrestrial Intelligence) program, has had to put its activities on hold due to funding problems.
The SETI program, initiated in the mid '80s, accumulated debts of 5 million dollars beyond its allocation of 50 million dollars from the National Science Foundation. The cessation of activity by the ATA looked like it would extinguish the hope of detecting signs of intelligent life for who knows how long. However, the possibility of selecting from within the Kepler list, those systems with the best chances of containing habitable worlds has made feasible a study with the Green Bank telescope (situated in West Virginia), the largest steerable radio telescope in the world, with a collecting area of over 7,800 m².
The current Green Bank Telescope began operation in 2000 after being completely rebuilt. The previous GBT collapsed catastrophically in 1988 while actually being used. The new technologies used in the new telescope make this 7,700 ton giant the most powerful single dish radio telescope, able to scan 300 times the frequency range of Arecibo. The Green Bank Telescope can therefore gather in a single day a quantity of data that would take Arecibo a year to collect!
The Green Bank Telescope has just started to "listen" to 86 planetary systems thought to be the most likely to contain terrestrial type planets. Although it would be too optimistic to expect to detect a non-natural signal from one of these, given the limited numbers involved, at least a targeted search has been started. Until now the entire sky was being searched.
The reduction of the enormous quantity of data that will be collected, about 1 gigabyte per second during many observations over a period of a year, will be largely reduced by the general public who participate in the SETI@home project.