| "Just the milky way" You mean the collection of stars that's 100,000 light years across? How long has life existed on Earth? Of that time, how long has life on Earth been generating signals that could be detected elsewhere? How much of the Milky Way has recieved those signals by now? 50,000 light year radius squared (let's favor your argument by calculating the milky way disc as 2D area) = 2.5 billion square light years Area our signals could have reached in the milky way over the past century of broadcasting: ~10,000 square light years So the intelligent life here and now, only a fraction of the life that's existed (much of which has had some degree of intelligence) has only reached about 0.0004% of the Milky Way by now, to say nothing for the drop of signal to CMB noise as it propagates. There's extensive discussion about the fine tuning argument for Earth regarding our gravity/propulsion to even be able to enter outer space, a threshold other intelligent life on a different planet may never be able to cross. Fermi's Paradox is silly when you dive into the nuances. |
Earth has a magnetic core and there are million things that generate EM radiation. Earth would have started radiating the moment it was created. It has a magnetic core as well. Now as per if somebody could read it 100000 light years away? Well the Sun was way hotter then and it would have obscured anybody looking this way.
Why aren't we seeing signs now, well maybe the signals are on their way but it may take another 20000 years to get them. I hope there is somebody here to receive and respond back.