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Our colleagues at The SETI Institute have recently added an interesting educational SETI Game area to their web site.  What follows is a response to their comparisons of the efficacies of the radio and optical approach to SETI.  There is a game here within the game which involves the SETI Institute regularly putting out arguments against Optical SETI and yours truly responding with counter-arguments.   I have made extensive use of the images that the SETI Institute has deployed on their "game" pages.  Let the fun continue!   See also The Politics of SETI and Book Reviews.


This image of NGC 2997 looks something like our own Milky Way galaxy.  The solar system is situated some about 30,000 light years from the center of our galaxy.  The Milky Way galaxy is about 100,000 light years in diameter. milkyway.jpg (14349 bytes)


andromeda.jpg (7002 bytes) Our nearest galactic neighbor is the famous Andromeda (M31) galaxy, which is located some 2.2 million light years from the Milky Way.   The distance is so vast and signal propagation times so long at light-speed (3 x 108 meters per second), that few people would think it worthwhile to attempt to establish SETI-type communications between galaxies using electromagnetic technology of any form.   Any species that attempts to do that is probably not very intelligent!   However, SETI-type communications over interstellar distances is quite a different question, and one-way or two-way communications between nearby stars, even as slow as light-speed, is something that could reasonably be contemplated.  As the interstellar distances increase, the issue becomes more problematic, just because of the time required for responsive communications.

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spectrum.gif (4562 bytes) If you click on this image, details about the optical spectrum from the ultra-violet to the infrared will be revealed.



cloud15.gif (28569 bytes) Part of this animated gif "borrowed" from the SETI Institute web site consists of the famous image of the "Gaseous Pillars".  This wonderful image of the Eagle Nebula (M16), the birthplace of stars, was captured by the Hubble Space Telescope in late 1995.  It has even been featured in the background of Star Trek Voyager and in Babylon 5, such is its beauty.  An image of these Gaseous Pillars has existed on the COSETI web site since this new, larger consolidated web site was activated in August 1997.  Click on the image to the left to see it in all its glory.  M16 is located about 7,000 light years from the earth.

The animated gif illustrates the severe attention of laser light that would occur if ETIs attempted to transmit a laser beacon through the cloud of gas and dust, while at the same time showing that microwaves can penetrate the cloud easily.  But that is not the whole story!


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Version 1.0
March 16, 1998


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