We can't send a strong enough radio signal to be detectable at any other nearby stars

The Three Body Problem is great, but it assumes the existence of weapons of ludicrous destructive power.. The only other time I've ever seen a piece of fiction where someone had that amount of destructive power was in a cartoon. (And even then I only saw it once)

If you assume that there's no faster-than-light space travel, it doesn't really make any sense to engage in interstellar conflict IMO. The same tech that would let you travel between the stars would also let you live in comfortable artificial habitats around your own home star, close enough to the rest of your civilization to be able to watch TV and keep up with HackerNews.

> The Three Body Problem is great, but it assumes the existence of weapons of ludicrous destructive power.. The only other time I've ever seen a piece of fiction where someone had that amount of destructive power was in a cartoon. (And even then I only saw it once)

That part doesn't seem to hard to me. A robotic spacecraft could install solar sales on a comet in such a way as to crash it into the target planet a few hundred years later. This could go unnoticed until it was too late by the target planet. Alternatively, a beam-powered probe (e.g. 'starwisp' or similar) moving at relativistic speeds could be crashed into the target planet.

Neither of these require cartoon physics.

how detectable would the EMP from nuclear explosions be? Obviously that is strong, but not very directed..

You do realize that there is gigantic nuclear reactor sitting about 93 million miles from where you are right now, right? An energy source so massive, it would only take a small fraction of it to heat and power several full planets. It would be like billions of nuclear explosions every second.

The Sun dwarfs anything we can do on Earth. Any arbitrary explosion of that sort wouldn't even register as noise next to the Sun. Our radio transmissions are directed and deliberate in a way that is noticeable even among the noise. Like watching scrambled HBO on an old cable box.

Yes. However I don't know if that is different. That is a roaring fire, whereas the https://en.wikipedia.org/wiki/Tsar_Bomba was a 58 megaton event which would have created a pulse. Electronic devices can sit in the sunshine all day, exposed to the roaring fire of the sun but a singular EMP can take them out? When you look for things, you look for what is different to its surroundings. Even when our own people are looking for planets around other stars, they are looking for an incredibly small change. They found something nearly 30,000 light years away like that.

Yes, we're close enough to Earth that it has a lot more affect on us than the Sun. And the Earth has a magnetic shield. Etc.

The Tsar Bomba did not destroy all life on the planet, did it? A simple solar flare is 5 to 10 magnitudes larger. Yes, small changes, but small changes that don't belong.

We are close enough to the Sun that even if that were detectable at the scale of the cosmos, the distance between the Earth and the Sun is a rounding error at the scales we are talking about.

Appreciate this. We are effectively in the Sun's atmosphere. The entire solar system is. Scale matters.

Maybe they're still on the way. We didn't start radio broadcasts until quite recently ago.