FaceDeer

But that's not actually true. We've been "broadcasting" the fact that there's life on Earth in the form of the spectrographic signature of an oxygen-rich atmosphere, which is a clear sign that photosynthesis is going on. There's no geological process that could maintain that much oxygen in the atmosphere. The Great Oxidation Event is when that started.

We have the technology to detect this kind of thing already, at our current level. Any civilization that could reach out and attack another solar system would be able to very easily see it.

Yeah, he had some good points before the sudden leap to genocide.

A car window is a lot easier to shatter than a fighter jet canopy.

Or, climb into the front seat and open the front door.

Well, "relatively cheaply" is a hard standard to nail down. I would say "no", though. Antimatter is very expensive to manufacture and store and you're going to need a lot of it. All of the energy that comes out of an RKV hitting its target has to be put into it in the first place, probably several times over given the inefficiencies likely inherent in the process.

Of course, because music belongs to the Record Labels. How dare it be made without their consent (and a cut being paid).

It's not your first option in an emergency. Normally you just open the door. Breaking the glass is several layers of things-not-working deep.

It doesn't look hidden to me, I expect I'd probably use that by accident myself.

Here it is.

You could have left at any time.

The problem for the Fermi paradox is that there's no reason to do stuff like that before we start colonizing other solar systems.

Also, how do you destroy a civilization that has a Dyson swarm already? That's not exactly an easy task, and if you insist on remaining stealthy yourself it's nigh impossible.

Relativistic missiles. Nothing moves faster than the speed of light. So if you can get a big rock to go 95% of the speed of light, we'd only be able to detect that it's coming right as it hits.

This is a very common answer to "how", but it comes with lots of problems in the Dark Forest context.

• If you actually calculate how much energy is required to boost a big rock up to that speed you run into lots of difficulties. It takes a lot, a heck of a lot. How does a civilization that is "hiding" accumulate that energy? How does it store it long-term?
• How is that energy actually put into the rock? This is basically a starship accelerating up to that speed and getting a starship up to that velocity is not easy even if you have the energy available. Does it have a rocket? The rocket equation for getting up to near-lightspeed requires ridiculous amounts of propellant. Is it beam-propelled? You're not being at all stealthy that way. How much acceleration can you get out of your system? It takes a full year at one Earth gravity of acceleration to get up near lightspeed, and that's a really high acceleration - you generally trade acceleration for efficiency so the faster you want to get up to speed the more energy you need and the noisier you'll be.
• It actually is possible to counter an RKV. It's much easier to hit and destroy an RKV than it is to launch it, all you need to do is get a pebble in its path. The key is detection, and the above points give some pretty good options for detecting it before and during launch. That gives you time to fire your countermeasures.

And ESPECIALLY if your civilization is still mostly planetbound.

Absolutely not guaranteed to be the case. Earth's civilization could have easily had offworld colonies by now if circumstances had been slightly different, so a Fermi paradox solution that requires reliably blowing up Earthlike civilizations before they can get offworld doesn't work. They're already too late.

As I said previously, Earth has been quite obviously life-bearing for at least 2 billion years. Why wait until something like an RKV is needed, and even that is not guaranteed? They could have destroyed life on Earth far easier, and thus far more stealthily, if they'd done it a billion years ago.