Sunday, April 13, 2014

Wow Signal – Brief Burst of Radio Waves

Wow Signal
The Search for Extra Terrestrial Intelligence, SETI, has seen many astronomers touring the sky with hopes of receiving artificially generated radio signals sent by alien civilization. Nicknamed the `Wow’, signal, saw a brief burst of radio waves detected by astronomer Jerry Ehman, on August 15, 1977, a strong narrowband radio signal, while he was working on a SETI project at the Big Ear radio telescope, of the Ohio State University which was then located at Ohio Wesleyan University’s Perkins Observatory in Delaware, Ohio.

The signal was so remarkable that Ehman circled it on the computer printout with a `Wow’, in the margin and unintentionally gave the received radio signal the name for which it became very famous. The signal had the unexpected hallmarks of non terrestrial and non solar system origin and it lasted for the full seventy two second window that Big Ear was ever able to observe and has not been detected again. This signal has been the subject of significant media attention ever since.

No Identification for Signal’s Source

No identification has been found for the signal’s source inspite of great efforts without repeated signal found which turns out to be a mystery. The only conclusion drawn was that if the signal could have originated in deep space then it could either be an astrophysical phenomenon which was never seen before or it could have been an intercepted alien signal.

After trying and failure in finding any repeat of the signal, the Wow signal researchers faced difficulty and Ehman became skeptical of its origin stating that `something suggest it was an Earth sourced signal that simply got reflected off a piece of space debris’, and when he made attempts to investigate the explanation, he faced more problems.

Signal’s Intensity

Wow Signal  Location
On investigations, it was found that the signal could have probably originated on Earth with likely reflection off a piece of space junk. The received signal being specific, the explanations required too many assumptions and a logical thinking pattern known as Occam’s razor pointed towards this signal with an astrophysical origin though it did not provide an explanation.

The signal’s intensity at the start was noticed to rise and fall over a period of 72 seconds, consistent with the Earth’s rotation with a single source tracking in the sky with the help of the Big Ear telescope which gave the signal a characteristic signature caused by object seen in the sky. This would be impossible to match for any Earth bound object.

Amazing Frequency – Sharp Transmission

The signal also stood out over the background noise found in deep space, about 30 times louder than anything else and the most amazing thing about it was its frequency which was sharp transmitting at only a single frequency.

Natural radio sources do not operate that way but spread across a range of frequencies, in other words, the same signal covers a broad band of transmission and the Wow signal is far from it showing only one specific frequency of 1420 MHz approximately which is also known as the hydrogen line, a frequency which is internationally banned from use by terrestrial radio signals due to its use in radio astronomy.

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