Note: I wrote this on my earlier blog hosted as http://parallelspirals.blogspot.com. I recovered the text from the WayBack Machine. This post appeared on February 21, 2011 as per the time stamp. I’m trying to collect here again all my old writings spread on various blogs.
Sir Arnold Wolfendale gave a public lecture at the Marathi Vignan Parishad offices located in Chunabhatti. I saw this place for the first time when I was in a bus and was stuck in the famous Priyadarshini traffic jam. I was interested in going to this place but like everything else never got around to going there. My friend, Suhas Naik-Sattam who works at the Nehru Planetarium informed me about the event through Facebook. The talk was easy to understand and punctuated by humour and his experience over the years.
The talk was a collaboration between National Centre for Science Communicators, Marathi Vignan Parishad, Khagol Mandal and International Union of Science Communicators. The talk was titled, “Search for Extra Terrestrial Intelligence”. Before beginning, he took a straw pole of the number of people who believed that we were alone in the Universe (or unique) and the number of people who thought we were not. Only 11 people in the whole room said that we were a unique species in the Universe. Rest of the audience, probably numbering about a 100 with school children involved said that we were not alone. Wolfendale said that over the years, when the same question was asked of the audience only 27% of the audience said that we were a common species.
Wolfendale then shared a story. He said a scientist retired and got himself a place at one of the places in England which end up with a sheer cliff and jagged rocks at the bottom of the cliff and the sea beneath. Once, exploring the stars, the man tripped over and by chance got hold of a branch on the drop. He called for help when a heavenly voice asked him to let go and that He would catch him. “Anybody else, out there?” asked the scientist. Wolfendale said he was looking for that anybody else too – not God.
He showed a picture of Jodrell Bank’s Lovell Telescope to demonstrate what a radio telescope looked like and then showed the Arecibo and explained how it was used to search for the above mentioned intelligence – life like us – was done from Arecibo. He spoke about expressions of people over the centuries from 13th century Chinese philosopher Teng Mu through Giordano Bruno and Copernicus and Galileo right upto the Kepler looking for planets in the Universe and wondering about the possibility of life on them.
He then showed the famous Drake Equation, a formula thought to predict the number of detectable civilizations in the Universe. He explained the various terms in the equation, spoke about the possibility of finding their values so that one could substitute them in the Equation to find a plausible result. In explaining these terms, he spoke of SETI and the search started in 1960 by Francis Drake to find the value for “the fraction of civilizations that develop a technology that releases detectable signs of their existence into space”. He spoke of the Mars meteorite activity and how it influenced the debate on “the length of time for which such civilizations release detectable signals into space”.
Wolfendale postulated possible time frames for which human like life form could evolve and exist. He guessed the number as 1 billion years. He spoke of solar flares that could damage the atmosphere occuring about once in a million years, an asteroid event like the dinosaurs once every 109 years and the life term of the Sun itself being about 4 billion years.
As he explained this, he gave the evolutionary timeframe and also explained about the rarity of an asteroid impact at Yucatan.
In the end, he said, if an alien civilization existed and one became extinct every billion years, we should be faced with a barrage of alien colonisations which was not happening and hence he sided with the 11 who said that we were a unique alien life form.
To me, the ending was an odd bit of reasoning and the talk ended quite suddenly. I did enjoy the initial part of the lecture, though.