One mad person after the other trying to say that there are civilizations out there that have nothing better to do than sending us radio signals with the power of entire stars.

Whether they are out there or not, is not currently known. That is the experiment. Welcome to science.

No one knows if they are there. What is undisputable is that with a little hard work (over many years) we can determine, for sure, whether or not they are broadcasting something we can detect. That work starts with the current SETI@Home.

IAirbuster, I don't think you have read my post clearly. I said "IF THIS IS TRUE (and I hope it is not)"....Don't sign up here 3 weeks ago and start flaming me for nothing.

Our own technological history has trended toward higher overall energy usage, not less. The Space Shuttle uses a lot more energy than a convoy of donkey carts. The street lamps of London leak more light skyward today than the gas lamps did a hundred years ago. Although individual devices tend to become more efficient, the sum total of energy expenditure goes up.

Of course, a very efficient civilization might find a way to capture and recycle most of its waste energy. Most SETI projects operate on the assumption that the alien civilization is not intentionally hiding from us.

But who says that they are limited to our level of technology?

Indeed. Given x billion years in this galaxy, it is unlikely that two civilizations would meet in the short time (few thousand years) during which they have current-human-like technology. So, statistics say we are FAR more likely to encounter civilizations which are hundreds of thousands to millions of years more advanced than us.

Meanwhile, I let my PC:s work in the Rosetta-project instead�

No. The current seti can detect the mega civilizations...those that are so technologically adavanced they would seem god-like to us. They might do things like harness entire stars to use as batteries, fission entire planets, etc...which might give off suspicious tera-tera-tera watt transmission we can pick up. Keep searching.

I think the question is interesting. The result would depend strongly on whether the emission is directed (such that a small beam contains all the energy) or non-directed. A directed beam can concentrate much more photons in a smaller area (or volume).

Hi
I've been thinking about the possibility to measure the signals from an "intelligent" radio source. For simplicity I used examples from our own radio technology. Let�s say that we have a radio transmitter sending at 100 MHz with 10 kW power. If that radio source was placed near the closest star to us it would give us a photon count of approximately one photon every 3 hours on a square meter. Is that really possible to measure with the radio telescopes and the settings they use for this project?