Hailing Frequencies Open

Hailing Frequencies Open - technology switch-over between...

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Hailing Frequencies Open, Captain A message was sent on November 16, 1974 to the globular cluster M 13. Unfortunately, since M 13 is about 25,000 light-years away, we will have to wait about 50,000 years for a reply. Messages have been attached to the Pioneer and Voyager spacecraft, but they will take thousands of years to reach the nearest stars. Our main mode of communication is the inadvertant messages we have been transmitting for several decades now: some of the signal in television and radio broadcasts leaks out to space and rushes outward at the speed of light. It takes many years for the radio and television signals to reach the nearest stars because of the great distances to even the nearest stars. So perhaps radio astronomers on other planets are watching the original broadcasts of ``Gilligan's Island'' or ``Three's Company'' and are seriously reconsidering their decision to say hello (message for television legal department: that is a facetious statement and is not to be taken as a serious statement about the quality of your boss' product). We are currently in a major
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Unformatted text preview: technology switch-over between television/radio broadcasts (over the air to cable) and telephone communication (land-line to cellular) that does affect how much noise and the type of noise we are making. Some searches for extraterrestrial signals are looking for brief optical (visible light) flashes because visible light can travel great distances out of the galactic plane and a tightly-focused beam of light (like a laser) can made to be many times brighter than a star. If the beam of light is pointed our way, we could see it over the glare of the star the extraterrestrials orbit. Also, the higher frequencies of visible light than radio means that a larger amount of information could be transmitted in a given amount of time than with radio. Perhaps the extraterrestrials would use radio signals to make their presence known and use lasers to beam information to us once we have started looking their direction....
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This note was uploaded on 12/15/2011 for the course AST AST1002 taught by Professor Emilyhoward during the Fall '10 term at Broward College.

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