I think we're a bit too late for radio silence. Even if our comms are indistinguishable from noise at that distance, I bet our previously detonated nukes would have sent distinctive pulses across the near cosmos.
I wonder, does SETI look for signs of alien nuclear wars?
Someone else can figure out the math, but I'm pretty sure the energy from all of the nukes that have been detonated, especially if you only count the open-air ones, is minuscule compared to what the sun gives off. That would mask any possible detection. I wouldn't be surprised if just the solar radiation that the earth reflects is enough to mask the nuclear blasts, unless you're viewing them from right inside the solar system.
The spectral signature would be quite different.
What kind of unique signs would a nuclear explosion create? Doesn't nuclear fission occur naturally?
Not really? Only in very rare exceptions. At least if you're talking about chain reaction fission.
Those gamma-ray bursts have to be coming from somewhere, I guess.
Gamma ray bursts are from interplanetary war? That's a terrifying thought.
My pet conjecture has always been that they're the interstellar equivalent of "Hold my beer and watch this..."
In Pellegrino and Zebrowski's The Killing Star, it's the know-it-all attitude in Star Trek that seals our fate.
It is extremely unlikely that superluminal travel exists. It would fundamentally violate so many physical laws (including causality) that our prior for that should be low indeed.
If they have the power to come to us, they certainly have the power to find us, silence or not.