Cool interactive site.

[Terryl]

Here is a cool site that gives you the option to increase or de-crease the numbers in the "Drake Equation".

This Equation is a formula to calculate the number of possible civilizations that may have a detectable radio signature.

Have fun....


http://www.pbs.org/wgbh/nova/origins/drak-flash.html

[StanW]

I arrived at 75.... a rather small figure.lol Would have been even lower if I hadn't used 50k for L.

[Terryl]

WOW

75 is still a large number, but we have only been listening for 50 years or so, and we as a civilization in whole only have a radio sphere* of about 100 light years so if we detect something within the next few years and send a message back, then it will be another 60 (we would have to decipher it and they would have to do the same) or 70 years before we get an answer.

It would be 100 years or so if someone out there heard us and answered back, less if they are closer to us.


*Radio sphere, the first true radio waves with enough power to leave the earth and with some form of intelligent signal.

These were transmitted around 1899 to 1901 by Marconi in his trans Atlantic experiments, it wasn’t till 1910 that it had spread all over the earth with enough stations to be called a sphere, (transmissions all over) and at the speed of light would be about 100 light years away.

This does not mean that someone out there could receive them as the signal would be so weak you would need an enormous antenna to do so, or some very very very sensitive equipment.

[Terryl]

And here is a problem at our end.

We have in the last few years just shut down a major part of our radio sphere, and that was “Analog TV Broadcasts”, these signals were powerful enough to travel to the ends of our solar system and beyond, if you were on lets say the closest next-door star system Alpha Centauri at 4.3 light years away, they could be watching shows from 4 years ago, get hooked into that soap opera then POOF we go digital, they could think we just blew our selves up.

Now for the problem at their end, they may still be in their Stone Age, or so advanced they don’t need radio or TV shows to keep them entertained, (they come watch us) or were stupid enough to blow them selves out of existence as a civilization by playing around with their new Dark Matter bombs..