Right. With this whole SETI thing, are we actually broadcasting an easily-decipherable signal ourselves? I know there was that Arecebo one in the 70’s, but that was just a one-off thing aimed at a tiny part of the sky, wasn’t it? Have we broadcast anything since then? Even something simple like a prime number sequence, aimed at a large proportion of the sky.
If not, why not? That seems a little silly to me. What makes us think the aliens would behanve any differently? We could both have our ears pressed against the door, so to speak, but neither of us has thought to knock.
Nice topic line, but I’m not sure exactly what it is you’re asking. Are you asking if the SETI project has broadcast any more signals to specific quadrants of the galaxy, and if not, why not?
Please clarify. I have a little time left to answer questions before the Mother Ship arrives, so…
“Why, sometimes I’ve believed as many as six impossible things before breakfast!” - the White Queen
There was also every broadcast TV and radio signal we’ve transmitted in the last 100 years.
Signals from the Earth have already hit hundreds or thousands of stars. There are a few dozen that are close enough for TV signals to have gotten there and for a return signal to have come back.
If a planet identical to Earth in every way, including CBS, NBC, etc, were orbiting one of the Centaurus group of stars, the current SETI search would not detect it.
If we had happened to be listening in the right direction, at the right time, and on the right frequency, with the right decoding algorithm, we might have received the original SETI signal broadcast.
It’s a big universe out there.
Tris
Imagine my signature begins five spaces to the right of center.
It certainly would. Or if it didn’t, it’s only because Alpha Centauri is in the southern hemisphere and SETI is currently done with northern hemisphere radio telescopes.
Because of NBC, CBS, et al. (especially long distance radars) Earth is a very bright object in the radio spectrum. At least out to about 50 light years (and further as TV and radar signals get further away from Earth). It stands out like a sore thumb, coming from what is otherwise an ordinary main sequence star (not normally emitters of much in the radio spectrum).
Now it’s true that parts of the E-M spectrum are reserved for radio astronomy, and if SETI is restricting its searches to those frequencies, it wouldn’t see much from an identical Earth. But I don’t think they restrict their searches that way.
