[sixdimensional]

Sci fi daydream here.

What would it take for us to actually try to make such a signal ourselves in space? Really huge explosions? I suppose one weird way to see if they could be alien signals is see if we can imitate them.

Of course, that would be no guarantee that we aren’t just making bird calls imitating the sounds of car alarms (or other birds for that matter). But, I mean, if we can detect these signals, if we could generate one, maybe some other civilization would too. And if we proved that any civilization of a certain state could use the same technique, it would at least lend more probability to the possibility that these are something not natural phenomena.

And who knows, when the alien armada invasion force shows up, you’d know for sure it worked! Ah, such reckless abandon.

[_1100]

The Three Body Problem is a first-contact trilogy of books that starts just like this:

Someone ponders what the most powerful thing in our area is (the sun) and then finds a way to influence it just enough so that it can send repeating signals. From there the alien armada heads our way and sets up the plot of the rest of the trilogy!

[runawaybottle]

Would it really take an Armada? Coronavirus infected 40k people, we have some of these viruses in labs. I’d send one agile team and drop a nice virus on Earth (minimal viable product).

[_1100]

In the book, they start by sending as little as 3 protons, and it completely debilitates humanity.

[DataGata]

The protons as you call them are a fun quirk of the science fiction genre, "How do we explain the Great Stagnation"? Fine Structure by Sam Hughes is the first book I've ever seen do it.

[mc32]

Maybe they’d have competition on the way here? I mean, if there is one intergalactic traveling life forms, why not multiple? Not that they have to be foes... but you can’t presume that they aren’t.

[sliken]

Well 1 watt across 1 Mhz for 1 second isn't a particularly power signal.

But 1 watt across 1 hz for 1 ns is a significantly more power signal that will propagate much better. In fact it's about 1e+15 times easier to detect. Hrm, maybe it's more like log(1e+15), but in any case it's quite helpful.

If we can get space based manufacturing working well we could start making solar powered lasers that orbit the sun. Ideally with a bot that self replicates. Say relatively small panels like 2 meters by 2 meters = 5444 watts (near earth orbit). Assume a 20% conversion ratio and some kind of energy storage. Maybe operate for a 1 ns per 10 minutes on a very narrow frequency with a particular target in mind. Time them all to transmit precisely so that the wave front reaches the target at precisely the same time.

5444 * 10 = 54,444 watt minutes * 20% conversion = 10,888 watt minutes. Released in 1ns would be as bright as 653,280,000,000,000 watts steady state. Obviously there are efficiencies and physical limits to consider. Although maybe not as much as you might think. For instance the worlds brightest laser is already 1 billion times brighter than the surface of the sun. Maybe settle for 1,000 times dimmer, but 1 million of them.

Make a few 1000 or a few million and you could easily outshine the sun for 1ns in a particularly narrow frequency. Ideally a frequency with minimum background noise and minimal absorption in the nearby interstellar mediums.

The system could also act as a defense system. Although given the solar -> energy storage -> laser inefficiencies not sure if the single frequency of the laser would be more effective than just a mirror.

Maybe count up the first 16 primes repeatedly to rule out any natural causes.

The three body problem uses some implausibly small amount of energy to get the sun to resonate in a way detectable from many light years away. Not sure that could work, but maybe a million sats could reinforce a natural resonance in the sun to accomplish similar. That would only be worth it if the sun acted like amplifier and not sure that's feasible.