To an alien civ, a sun appearing and disappearing on an interval would be a pretty big red flag.
Now that i come to think of it, a Dyson sphere would probably be the best dead giveaway we could ever make. Effectively turning our sun into an oversized blinker.
Signals, so weak i might add that they will most likely be disregarded as part of the cosmic background radiation.
Think of it this way. If an alien civ is looking for Earth right now, the best lead they have is some almost non-existant radio signals that only exist within a range of 150 ly tops.
Considering how little of a mark their activities would yield on a cosmic scale, it's like looking for an single atom in a haystack.
And have a very low area of influence no greater than 50 light years.
I don't believe however there are any alien races that posess interstellar capability beyond the speed of light. Which means that this type of life must survive thousands of years.
A planet with less extinctions or better conditions could have easily developed life at an earlier stage.
Which, in all honestly is likely incorrect given the amount of mass extinctions life has had to endure to develop this far.
@kokansei yes, it's generally based on the assumption that the time it took intelligent life to develop on Earth is the same for intelligent life to develop elsewhere.
Until we find ET life, we are the only known life in the universe. We are treating that status with the same carefulness as a stunt actor on Jackass.
Point being, the choice for humanity to confine themselves to one planet will be the worst decision we've ever made. And in time, it will be a lethal one.
Not to mention even the possibility of flat out living in space to some degree.
If we can do that, the habitable space for humans can grow to include ELW and terraformable worlds.
Given the right level of technology we might be able to make certain uninhabitable worlds habitable. That's the Mars experiment.
What argument are we talking about though?
Maybe not the best analogy, but you get the idea.
Well, trying to find Earth like worlds right now is like trying to count the raindrops with a specific composition in a storm 20 miles away using nothing more than an old pair of binoculars.
Our spacecraft used to be a sign of the times, the beginning of a new future for humanity. Today, they are a museum piece to a future that never came. Crushed by economic reality, bureaucracy and false intentions.
