While NASA talks about 'Are we alone?' as a number one question, they are putting zero money into searching for intelligent life. There's a big disconnect there.
The story seems to be that almost every star has a planetary system... and, also, the definition of 'habitable zone' has expanded. In our system, it used to be that only Mars and Earth were potentially habitable. Now we've got an ocean on Europa... Titan.
Right now, there could well be messages from the stars flying right through this room. Through you and me. And if we had the right receiver set up properly, we could detect them. I still get chills thinking about it.
There was a magic about pulsars... no other things in the sky had such labels on them. Each one had its own distinct pulsing frequency, so it could be identified by anybody, including other creatures, after a long period of time and far, far away.
Nature never uses prime numbers. But mathematicians do.
The pulsar map is not dangerous at all. It will likely never even be seen by extraterrestrials.
In 1957, I was studying the Pleiades star cluster at Harvard University's radio observatory. On one occasion, we saw an added feature in the data. It turned out to be an amateur radio enthusiast near the observatory, but at the time, I thought we had detected clear evidence of another civilisation.
We send messages all the time, free of charge. There's a big shell out there now, 80 light-years around us. A civilization only a little more advanced than we are can pick those things up.
If you're sending a message to extraterrestrials, what you want to send is what's special about us and our planet - what is unusual. Now, that's not basic chemistry or mineralogy; it's pretty much the cultural stuff and the consequences of evolution.
No company is hiring anyone to search for messages from aliens. Most people don't seem to think there's much benefit to it. The lack of interest is, I think, because most people don't realize what even a simple detection would really mean.
It now appears that essentially every star has a planetary system. In the very beginning, we thought at best half.
People presume we've been somehow monitoring the entire sky at all frequencies, all the time, but we haven't yet been able to do any of those things. The fact is, all the SETI efforts to date have only closely examined a couple thousand nearby stars, and we're only just now learning which of those might have promising planets.
