Posts Tagged ‘SETI’


Search for Extra-terrestrial Intelligence – SETI

July 20, 2009

Cygnus Star Cloud

Cygnus Star Cloud

Photo Courtesy: (Image may be copyrighted by them, hence do not use for commercial purposes)

“Either we are totally alone in this universe. Or we are not. Both the possibilities are equally staggering”

Consider this: It’s been about 4.6 billion years since the formation of earth. The first micro-organisms were formed about 500 million years after that. The dinosaurs were extinct before 65 million years ago and the ancestor of human beings (homo sapiens) called Australopitheans came to existence about 5-6 million years ago. We have been studying the properties of radio waves (like light, sound and other communication waves etc) only for the last 100 years.

In this background, how difficult would it be to search for extra terrestrial organisms that are intelligent enough to transmit radio waves (Or laser beams), in the planets surrounding the stars in neighbouring galaxies? That’s one of the activities of an organization called SETI – Search for Extra Terrestrial Intelligence, which has contributing members and scientists from across the world and multiple observatories to conduct the research from. They use radio telescopes (which are either like a big dish antenna – largest being about 305 meters in diameters) or they use an array of smaller antenna systems and a central control unit to assimilate the data collected by these array of antennas.

The challenge facing such a research initiative is enormous – First, they need a lot of funding (Right now, they are partially funded by NASA and individuals like Allen, who is a Co-Founder of Microsoft), second they need to integrate cutting edge technology in various fields like optical lenses, radio astronomy, molecular biology, information systems and a lot more. The third – probability of finding out a radio wave communication from a distant galaxy may be very near to 0%, if at all they use the same ways of transmitting signals like us. There is only one consolation: The electro-magnetic spectrum, which comprehensively represents all the type of waves that we know of(light, etc.) can be completely scanned by the technology available today in a wide range of frequencies (comprehensive, as far as we know). And some of them do travel long distances.

Speaking of distances, to get a view of the universe that we know, consider this: The Sun is just one of the four billion stars (that we know), and the nearest star (Other than Sun) is 4.2 Light Years away. Make no mistake in reading it – If we travel at the speed of light (3 x 10 power 8 meters/sec), then we would take 4.2 years to reach our nearest star. With the current maximum speeds available (Even with Super Sonic Jet planes and space crafts), it would take thousands of years for us to physically reach there or send a space mission to these places. And our nearest galaxy is 2.5 million light years from us! There are thousands of such galaxies, as far as 200 – 300 light years.

To add to all those woes, a man called Albert Einstein has calculated that the speed of light is the fastest (or the best speed) that any particle could hope to travel. All the waves (Including light) travel in that speed. If that assumption is true, we may never be able to reach certain galaxies even if sufficient technology is developed in future. By the way, the light we see from the stars in the night were actually sent from the stars before many years but we are able to see them only now, as the light has to travel incredibly long distances to reach us!

Complicating things further is our ignorance of planets that surround the solar system – Though Mars and certain moons (Like Titan, one of the moons in Saturn) do seem to contain some favourable conditions for life (At least extinct life or micro-organic life), we have not been able to verify it till date. The farthest that a man made object has ever travelled is about 106 times as far as the Sun (By a satellite called Voyager 1) and the sun’s rays take just 8 minutes to reach earth!

But there are considerable advances made in the field of radio-astronomy. The light/radio waves from a planet, if detected, could be used to construct a spectrum that would tell what type of atmosphere a planet has, and some other vital information about the conditions of the planet, which could be used to determine if a planet in far away galaxy has a possibility of creating/ sustaining life. In fact, about 350 planets have been discovered orbiting far away stars.

One related piece of information is the launch of Kepler Spacecraft (March 2009) by NASA which seeks to observe and analyse light waves (Using CCD cells) from a galaxy called Cygnus (which has a large density of stars) and hence more probability of a planet coming in between the star and the spacecraft, for it to observe from an area in space, with out being blocked by the sun. The above picture is the star cloud of this Cygnus galaxy.

Whether they are able to detect extra terrestrial intelligence in a distant planet or not, their initiatives fuel the growth and development of cutting edge technologies that find applications in a lot of fields on earth!

You could visit the ‘Non-Fiction’ section of this blog, for similar articles.

Destination Infinity

You could also help the initiatives of SETI by participating in the SETI@home project.