[BradyLS]

In Carl Sagan’s book _Contact,_ he points out that we’ve been broadcasting television signals into the cosmos since the 30s. It’s only gotten worse since.

In that time, we’ve not been visited by beings with faster-than-light ships—that we’re aware of. If that’s the case, we can pretty much know that nothing travels faster than the speed of light and we’re relatively safe from beings that are centuries distant. We could broadcast for a long time (in human-years) and never worry about a visitation. Not having found any evidence of visitors on the nearby planets (yet) reinforces the idea that there are none around for perhaps hundreds or thousands of light-years.

On the other hand, if we have been visited by beings with advanced technologies that allow FTL travel, then they know about earth and its inhabitants and where we are in our development. We couldn’t hide it so broadcasting (or not) won’t change anything. They likely control the local planets and stars we’d one day get around to exploring and maybe that’s when formal contact would be made.

[PIF]

In that time, we’ve not been visited by beings with faster-than-light ships—that we’re aware of. If that’s the case, we can pretty much know that nothing travels faster than the speed of light and we’re relatively safe from beings that are centuries distant.

---

A broadcast only give the direction of the broadcaster, not the location. There are millions of stars between us and a possible attacker; the attacker would have to send scouts along that line before locating the source. That’s the good news; the bad news is 3 unexplained extra-solar objects have already passed through our system.

[jeffc]

Was Sagan referring to the Historical Documents. You know, the ones that include Gilligan's Island? ("Those poor people...")

[fso301]

In Carl Sagan’s book _Contact,_ he points out that we’ve been broadcasting television signals into the cosmos since the 30s. It’s only gotten worse since.

None of those signals generated on Earth will be intelligible at inter-stellar distances.

[tbw2]

What an Alien SETI Program Would Learn from Earth’s Signals
https://hubpages.com/technology/What-an-Alien-SETI-Program-Would-Learn-from-Earths-Signals

[SunkenCiv]

/bingo