>>25891 (OP)
They'd have to know exactly where to look, and how to filter it out from the noise. For example we missed a complete STAR SYSTEM just a few light years from here (Luhman 16), and we didn't detect it because of what light it emitted. We detected it because its gravity had jiggled a brighter star enough, that using jiggle mathemagic, we were able to approximate its position.
Basically taking a single image, and using human to figure it out, our telescopes can only see main sequence stars within a few light years.
The reason how we can see other stars is this:
1. Telescope takes a few seconds of high resolution video.
2. This 500 terabyte video fills a massive server.
3. They then disconnect and load a server on a truck, and drive it to a supercomputer. most telescopes are on mountains and dont have internet, much less bandwidth needed to transfer such a large amount
4. The supercomputer then analyzes it pixel by pixel for like 20 years, before identifying individual stars.
>>25894
Radio waves actually stop being intelligible after about 0.5 light year, and its much too quiet to be detected anyway. A fucking neutron star burst was barely detectable with shitscopes for most radio astronomy history. To put in perspective a burst of radio from a neutron star or a pulsar is going to be more powerful in a single second than the combined radio emissions of humanity for all its history and the next couple of million years as well.
Now Russia is going to do something cool and put two radio telescopes in high orbit on opposite sides of the earth, and use some math magic to simulate a "dish" the size of their orbit (100,000km radius) and that might detect some aliens with radios if they lived within 8 lightyears of us.
